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CHICKEN User`s Manual - The User`s Manual

1. 26 3 regexp procedure regexp STRING IGNORECASE IGNORESPACE UTF8 Returns a precompiled regular expression object for string The optional arguments IGNORECASE IGNORESPACE and UTF8 specify whether the regular expression should be matched with case or whitespace differences ignored or whether the string should be treated as containing UTF 8 encoded characters respectively 26 4 regexp procedure regexp X 26 Unit regex 110 CHICKEN User s Manual The User s Manual Returns t if X is a precompiled regular expression or f otherwise 26 5 string match 26 6 string match positions procedure string match REGEXP STRING START procedure string match positions REGEXP STRING START Matches the regular expression in REGEXP a string or a precompiled regular expression with STRING and returns either f if the match failed or a list of matching groups where the first element is the complete match If the optional argument START is supplied it specifies the starting position in STRING For each matching group the result list contains either f for a non matching but optional group a list of start and end position of the match in STRING in the case of string match positions or the matching substring in the case of string match Note that the exact string is matched For searching a pattern inside a string see below Note also that st ring match is implemented by calling st ring search with the
2. oci re n apre er E EE EEE O E EEEE AER reet EE 30 9 Brea 30 10 ee E DELS oerte et dace v eese e ennt Feel re tek no vu ERE Aane eR Re EET daaa ie Vae 30 11 tcp abandofri pott 55 5 ec etre ire e e EPOR E ex E E UR E RE SEEE OPERE OE NPRRMA ETRAS EIA NN TA is EFE EN O SY MOPS I OM OMSL T ODE LR SS eni iik AEE ES ARE ANE EEN E Eee eie SN BE 32 MES EE DD MA AMP OME EE 32 1 5 HUN PomtEr m NT SEET one rhe I GERE NIRE ERR nests ETE NR EEEE 321 7 OM aba diia SAR NON 521 9 e lee 32 1 10 pointer 0D eCt EE SAA eee ente t tee Ie gu eee ente ee RR ERE ARMEN adde SDA AD ee EE EE ENS EE 32 1 14 enee Ee 32 1 15 pomters LE ET SPA EE EE 32 1 1 7 pointer s3 EE 32 1 18 pointer 32 Tef E 32 1 19 ee Ee EE SE DOME ET E AA Seth ore eite tbe tette tenir e Pee hne eerie Chet e e ned iE oidini 32 1 22 ee Ee RE 32 1 23 pomters LTE SIR A ree reat rs inr Mose en e e erae eeu Eres ee tae E en RE REN ERR E ERES 32 1 25 pointer E 32 1 26 pointer EA 32 1 27 ee E Sheet Eege A AAA XV CHICKEN User s Manual The User s Manual Chicken User s Manual 32 Unit lolevel 232 2 Taeg d politesse e n e eere ete ut E E AANEEN eoe ss nets Ele inches unde En Utente eos te aee kE eaea eN Si 162 32 2 1 tag et T T 162 232 2 2 t geed pornter E 163 CPP ai RR 163 32 3 Extending procedures With data iiie ette tte ern eerte aene ted dae Fere tiet en rentes une ele dee editus 163
3. E 56 VELO Ke Ee EE 56 111 CHICKEN User s Manual The User s Manual Chicken User s Manual 17 Parameters 1 d DMO EI EE 56 T712 t p prompt rii 56 TEA reset handlet EE 57 L NODE E 58 E tese rre tre e rei mere Ere e PESE eren pres ed esteri a tener pere e Rorvx EA b eding 58 IS ERE di A M 58 EAS DN 58 E BE 58 18 LA E E 58 18 1 5 DIS E Oi A A ads 58 RR E e EN 58 EIN em 58 EE ee edel 59 VS Ebenen asi 59 VS MOR EE 59 E A T E A E E 59 KR EE 59 VS ACVB EE 59 RRE entre E 59 E EE 59 KSE en RE 59 GER REN 59 LAS iia 59 I9 1219 X3 A O OA 60 AA E 60 Ka RE 60 E EE 60 LEE E DE D DEE 60 E MEE 60 E EE 60 KR E 1101 EE 60 19 1 2 7 EE 60 18 1 28 RE 60 IE Aon RE 61 SAID DE ID ET 61 18 1 9 RN 61 18 1 32 DE 61 1821233 REY 61 181 34 One E n 61 18 135 er 61 18 1 36 er 61 UL E ii id naa De tained aes 61 VPS VBS EE 61 SE EE 62 T8140 p gt DELLI 62 LS TAT EE 62 LACA ON 62 18 WAS RE 62 EP O 62 EPA IN 62 16 22 currentzerror DOEFL AA ee 63 1v CHICKEN User s Manual The User s Manual Chicken User s Manual 18 Unit library EPA cient erre rre eerte P E E Re eee oe e eee tena e eub Ra A de veg ue Saee E C e NASo 63 18 24 port tiatrie iii aid ridad 63 EPA INS 63 PAR OR 63 E A A E H 64 Be EE TE 64 E ENEE 64 18 3 eI SHIRE TUTTO 64 18 4 Strip 010 E 64 ERA nieis iroie opeen eE E E E E E E aE E DERESE
4. Copies the given files into the examples directory which is usually prefix share chicken examples equivalent to CHICKEN HOME examples or make pathname chicken home examples Note that the files listed in this property should not be listed in the normal list of files to install passed to install extension This is the only exception other files that are installed in the repository must be given in the file list 41 4 1 6 exports extension property exports EXPORT Add export information to the generated extension information EXPORT may be a symbol naming an exported toplevel variable or a string designating a file with exported variables as generated by the emit exports option or the emit exports declaration specifier 41 4 1 7 static extension property static STRING If the extension also provides a static library then STRING should contain the name of that library Used by CSC when compiling with the static extensions option 41 4 1 8 static options extension property static options STRING Additional options that should be passed to the linker when linking with the static version of an extension see Static above Used by CSC when compiling with the static extensions option All other properties are currently ignored The FILELIST argument may also be a single string 41 4 2 install program procedure install program ID FILELIST INFOLIST Similar to install extension but installs
5. All errors related to failing network operations will raise a condition of kind exn i o network 30 1 tcp listen procedure tcp listen TCPPORT BACKLOG HOST Creates and returns a TCP listener object that listens for connections on TCPPORT which should be an exact integer BACKLOG specifies the number of maximally pending connections and defaults to 4 If the optional argument HOST is given and not f then only incoming connections for the given host or IP are accepted 30 2 tcp listener procedure tcp listener X Returns t if X is a TCP listener object or f otherwise 30 3 tcp close procedure tcp close LISTENER Reclaims any resources associated with LISTENER 30 4 tcp accept procedure tcp accept LISTENER Waits until a connection is established on the port on which LISTENER is listening and returns two values an input and output port that can be used to communicate with the remote process Note this operation and any I O on the ports returned will not block other running threads 30 5 tcp accept ready procedure tcp accept ready LISTENER Returns t if there are any connections pending on LISTENER or f otherwise 30 Unit tcp 154 CHICKEN User s Manual The User s Manual 30 6 tcp listener port procedure tcp listener port LISTENER Returns the port number assigned to LISTENER If you pass 0 to tcp Listen then the system will choose a port number for you 30 7 tcp listen
6. EXPRESSION Treats EXPRESSION as a comment 13 3 External Representation CONSTRUCTORNAME DATUM Allows user defined extension of external representations For more information see the documentation for SRFI 10 13 4 Syntax Expression EXPRESSION An abbreviation for Syntax EXPRESSION 13 5 Location Expression EXPRESSION An abbreviation for Location EXPRESSION 13 6 Keyword SYMBOL Syntax for keywords Keywords are symbols that evaluate to themselves and as such don t have to be quoted 13 Non standard read syntax 27 CHICKEN User s Manual The User s Manual 13 7 Multiline String Constant lt lt TAG Specifies a multiline string constant Anything up to a line equal to TAG or end of file will be returned as a single string define msg lt lt END Hello world she said END is equivalent to define msg Hello world she said 13 8 Multiline String Constant with Embedded Expressions lt TAG Similar to lt lt but allows substitution of embedded Scheme expressions prefixed with and optionally enclosed in curly brackets Two consecutive s are translated to a single define three 3 display lt E0F This is a simple string with an embedded character and substituted expressions three 99 gt three 99 three is three EOF prints This is a simple string with an embedded character and substituted expressions three
7. 29 1 2 apropos list procedure apropos list SYMBOL PATTERN ENVIRONMENT Like apropos but returns a list of matching symbols 29 2 Pathname operations 29 2 1 absolute pathname procedure absolute pathname PATHNAME Returns t if the string PATHNAME names an absolute pathname and returns f otherwise 29 2 2 decompose pathname procedure decompose pathname PATHNAME Returns three values the directory filename and extension components of the file named by the string PATHNAME For any component that is not contained in PATHNAME f is returned 29 Unit utils 149 CHICKEN User s Manual The User s Manual 29 2 3 make pathname 29 2 4 make absolute pathname procedure make pathname DIRECTORY FILENAME EXTENSION SEPARATOR procedure make absolute pathname DIRECTORY FILENAME EXTENSION SEPARATOR Returns a string that names the file with the components DIRECTORY FILENAME and optionally EXTENSION with SEPARATOR being the directory separation indicator usually on UNIX systems and on Windows defaulting to whatever platform this is running on DIRECTORY can be f meaning no directory component a string or a list of strings FILENAME and EXTENSION should be strings or f make absolute pathname returns always an absolute pathname 29 2 5 pathname directory procedure pathname directory PATHNAME 29 2 6 pathname file procedure pathname file PATHNAME 29 2 7 pathname extension p
8. 32 4 12 static byte vector gt pointer 166 CHICKEN User s Manual The User s Manual 32 5 3 object evicted procedure object evicted X Returns t if X is a non immediate evicted data object or f otherwise 32 5 4 object size procedure object size X Returns the number of bytes that would be needed to evict the data object X 32 5 5 object release procedure object release X RELEASER Frees memory occupied by the evicted object X recursively RELEASER should be a procedure of a single argument a foreign pointer object to the static memory to be freed and defaults to f ree 32 5 6 object unevict procedure object unevict X FULL Copies the object X and nested objects back into the normal Scheme heap Symbols are re interned into the symbol table Strings and byte vectors are not copied unless FULL is given and not f 32 6 Locatives A locative is an object that points to an element of a containing object much like a pointer in low level imperative programming languages like C The element can be accessed and changed indirectly by performing access or change operations on the locative The container object can be computed by calling the location gt object procedure Locatives may be passed to foreign procedures that expect pointer arguments The effect of creating locatives for evicted data see obj ect evict is undefined 32 6 1 make locative procedure make locative EXP INDEX Create
9. Stores the unsigned byte N at the address designated by PTR 32 1 21 pointer s8 set procedure pointer s8 set PTR N procedure set pointer s8 ref PTR N Stores the signed byte N at the address designated by PTR 32 1 22 pointer u16 set procedure pointer ul6 set PTR N procedure set pointer ul6 ref PTR N Stores the unsigned 16 bit integer N at the address designated by PTR 32 1 23 pointer s16 set procedure pointer s16 set PTR N procedure set pointer s16 ref PTR N Stores the signed 16 bit integer N at the address designated by PTR 32 1 24 pointer u32 set procedure pointer u32 set PTR N procedure set pointer u32 ref PTR N Stores the unsigned 32 bit integer N at the address designated by PTR 32 1 19 pointer f64 ref 161 CHICKEN User s Manual The User s Manual 32 1 25 pointer s32 set procedure pointer s32 set PTR N procedure set pointer s32 ref PTR N Stores the 32 bit integer N at the address designated by PTR 32 1 26 pointer f32 set procedure pointer f32 set PTR N procedure set pointer f32 ref PTR N Stores the 32 bit floating point number N at the address designated by PTR 32 1 27 pointer f64 set procedure pointer f64 set PTR N procedure set pointer f64 ref PTR N Stores the 64 bit floating point number N at the address designated by PTR 32 1 28 align to word procedure align to word PTR OR INT Accept
10. file lock blocking PORT START LEN Similar to file Lock but if a lock is held on the file the current process blocks including all threads until the lock is released 28 10 3 file test lock procedure file test lock PORT START LEN Tests whether the file associated with PORT is locked for reading or writing according to whether PORT is an input or output port and returns either f or the process id of the locking process 28 10 4 file unlock procedure file unlock LOCK Unlocks the previously locked portion of a file given in LOCK 28 11 Signal handling 28 11 1 set alarm procedure set alarm SECONDS Sets an internal timer to raise the Signal alrm after SECONDS are elapsed You can use the set signal handler procedure to write a handler for this signal 28 11 2 set signal handler procedure set signal handler SIGNUM PROC Establishes the procedure of one argument PROC as the handler for the signal with the code SIGNUM PROC is called with the signal number as its sole argument If the argument PROC is f then any signal handler will be removed Note that is is unspecified in which thread of execution the signal handler will be invoked 28 10 2 file lock blocking 132 CHICKEN User s Manual The User s Manual 28 11 3 signal handler procedure signal handler SIGNUM Returns the signal handler for the code SIGNUM or f 28 11 4 set signal mask procedure set signal mask SIGLIST
11. procedure file execute access FILENAME These procedures return t if the current user has read write or execute permissions on the file named FILENAME 28 8 3 read symbolic link 127 CHICKEN User s Manual The User s Manual 28 9 6 change file mode procedure change file mode FILENAME MODE Changes the current file mode of the file named FILENAME to MODE using the chmod system call The perm variables contain the various permission bits and can be combinded with the bitwise ior procedure 28 9 7 change file owner procedure change file owner FILENAME UID GID Changes the owner information of the file named FILENAME to the user and group ids UID and GID which should be exact integers using the chown system call 28 9 8 current user id 28 9 9 current group id 28 9 10 current effective user id 28 9 11 current effective group id procedure current user id procedure current group id procedure current effective user id procedure current effective group id Return the user and group ids of the current process 28 9 12 process group id procedure process group id PID Returns the process group ID of the process specified by PID 28 9 6 change file mode 128 CHICKEN User s Manual The User s Manual 28 9 13 group information procedure group information GROUP If GROUP specifies a valid group name or group id then this procedure returns a list of four values the grou
12. procedure rassoc KEY LIST TEST Similar to ASSOC but compares KEY with the cdr of each pair in LIST using TEST as the comparison procedures which defaults to eqv 20 1 5 butlast procedure butlast LIST Returns a fresh list with all elements but the last of LIST 20 Unit extras 87 CHICKEN User s Manual The User s Manual 20 1 6 chop procedure chop LIST N Returns a new list of sublists where each sublist contains N elements of LIST If LIST has a length that is not a multiple of N then the last sublist contains the remaining elements c d 3 gt a b c d 20 1 7 compress procedure compress BLIST LIST Returns a new list with elements taken from LIST with corresponding true values in the list BLIST define nums 99 100 110 401 1234 compress map odd nums nums gt 99 401 20 1 8 flatten procedure flatten LIST1 Returns LIST1 concatenated together with nested lists removed flattened 20 1 9 intersperse procedure intersperse LIST X Returns a new list with X placed between each element 20 1 10 join procedure join LISTOFLISTS LIST Concatenates the lists in LISTOFLISTS with LIST placed between each sublist LIST defaults to the empty list e join c d 0 r s ab join p q join could be implemented as follows define join lstoflsts optional lst apply append intersperse lstoflists lst 20 1 6 chop 88 C
13. t 45 7 How can change match error control during compilation Use eval when like this eval when compile match error control unspecified 45 8 Why doesn t CHICKEN support the full numeric tower by default The short answer chicken setup numbers csi q 1 gt use numbers The long answer There are a number of reasons for this For most applications of Scheme fixnums exact word sized integers and flonums 64 bit floating point numbers are more than sufficient Interfacing to C is simpler Dispatching of arithmetic operations is more efficient There is an extension based on the GNU Multiprecision Package that implements most of the full numeric tower see http www call with current continuation org eggs numbers html 45 9 How can specialize a generic function method to match instances of every class Specializing a method on lt object gt doesn t work on primitive data objects like numbers strings etc so for example define method foo x lt my class gt define method foo x lt object gt 45 5 Why are constants defined by define constant nothonoured in case constructs 223 CHICKEN User s Manual The User s Manual foo 123 will signal an error because to applicable method can be found To specialize a method for primitive objects use lt top gt define method foo x lt top gt 45 10 Does CHICKEN support native threads
14. the number of days since Sunday 0 6 yday 7 the number of days since January 1 0 365 dstflag 8 a flag that is true if Daylight Saving Time is in effect at the time described timezone 9 the difference between UTC and the latest local standard time in seconds west of UTC 28 13 3 memory mapped file pointer 137 CHICKEN User s Manual The User s Manual 28 14 2 local time gt seconds procedure local time gt seconds VECTOR Converts the ten element vector VECTOR representing the time value relative to the current timezone into the number of seconds since the first of January 1970 UTC 28 14 3 local timezone abbreviation procedure local timezone abbrevtiation Returns the abbreviation for the local timezone as a string 28 14 4 seconds gt string procedure seconds gt string SECONDS Converts the local time represented in SECONDS into a string of the form Tue May 21 13 46 22 1991 n 28 14 5 seconds gt utc time procedure seconds gt utc time SECONDS Similar to seconds gt Local time but interpretes SECONDS as UTC time 28 14 6 utc time gt seconds procedure utc time gt seconds VECTOR Converts the ten element vector VECTOR representing the UTC time value into the number of seconds since the first of January 1970 UTC 28 14 7 time gt string procedure time gt string VECTOR Converts the broken down time represented in the 10 element vector VECTOR into a string of the form
15. truncate ftruncate file unlock fentl file write write file write access access get groups getgroups get host name gethostname initialize groups initgroups local time seconds mktime local timezone abbreviation localtime 28 21 How Scheme procedures relate to UNIX C functions 144 CHICKEN User s Manual The User s Manual map file to memory mmap open input file fdopen open output file fdopen open input pipe popen open output pipe popen port gt fileno fileno process execute execvp process fork fork process group id getpgid process signal kill process wait waitpid close input pipe pclose close output pipe pclose read symbolic link readlink seconds gt local time localtime seconds gt string ctime seconds gt utc time gmtime 28 21 How Scheme procedures relate to UNIX C functions 145 CHICKEN User s Manual The User s Manual set alarm alarm set buffering mode setvbuf set file position fseek seek set groups setgroups set signal mask sigprocmask set group id setgid set process group id setpgid set user id setuid set root directory chroot setenv setenv putenv sleep sleep system information uname terminal name ttyname terminal port isatty time gt string asctime unsetenv putenv unmap file from memory munmap 28 21 How Scheme procedures relate to UNIX C functions 146
16. 22 14 byte vector gt u32vector 22 15 byte vector gt s32vector 22 16 byte vector gt f32vector 22 17 byte vector gt f64vector procedure byte vector gt u8vector BYTE VECTOR procedure byte vector gt s8vector BYTE VECTOR procedure byte vector gt ul6vector BYTE VECTOR procedure byte vector gt sl6vector BYTE VECTOR procedure byte vector gt u32vector BYTE VECTOR procedure byte vector gt s32vector BYTE VECTOR procedure byte vector gt f32vector BYTE VECTOR procedure byte vector gt f64vector BYTE VECTOR 22 9 f64vector gt byte vector 104 CHICKEN User s Manual The User s Manual Each of these procedures return a vector where the argument BYTE VECTOR is taken as a packed representation of the contents of the vector The argument byte vector shares memory with the contents of the vector 22 18 subu8vector 22 19 subu16vector 22 20 subu32vector 22 21 subs8vector 22 22 subs16vector 22 23 subs32vector 22 24 subf32vector 22 25 subf64vector procedure subu8vector U8VECTOR FROM TO procedure subul6vector U16VECTOR FROM TO procedure subu32vector U32VECTOR FROM TO procedure subs8vector S8VECTOR FROM TO procedure subsl6vector S16VECTOR FROM TO procedure subs32vector S32VECTOR FROM TO procedure subf32vector F32VECTOR FROM TO procedure subf64vector F64VECTOR FROM TO Creates a number vector of the same type as the argument vector with the elements a
17. 28 19 Setting the file buffering mode eee cte cans cvnsovcacedsnaccedanncvaceesdevesaaccnedsenscecentecvstaeauas 141 28 19 1 set buttering Tode esee teret A anh cas cdeneacesticessastevadesee 142 28 20 NR 142 26 20 terminal n ame recorrer ed eege ENEE e Ee ed 142 25 20 2 termal das a 142 28 21 How Scheme procedures relate to UNIX C functions essere 142 28 22 Wrnidows spectfIC DO 6S uen rete tret ote e a e Ere Ee Ld a ee e e ERU ra eu e Fei Re EST Ee 147 28 22 sp wn overl y o erret ase IR E GT TURO SERE ARE TUO OPEN OR DR PRRM EOD ASE 147 2822 2 SPAWI EE 147 28 223 A NN 148 28 22 4 SPAWI NOWAI O EE 148 28 22 5 spawn detachi EE 148 DOERR DEENS Re edge 148 SAM RT T B 149 29 1 Environment RR 149 20 1 1 aprOpO Ss E 149 29 12 aptopossliSt o E etus eerta secede eoe rete ou RE RE E esee a etas 149 29 2 LAS e E 149 29 2 1 absolute pathiname oec eere rH HERE RAS CERIS coumneenasea danegsabessresedaie EES 149 29 2 2 decompos pathmnamie e n eerte tte a one d e e i EET PER Vue un 149 IAS E TE 150 29 2 4 make absolute oathuame eene nest nhr enne teretes cnn na kisiera 150 29 2 5 patlinatne difeCtory eer eed e EG HEU PRAE CERE FORE edad sven nad dcir diras 150 APA RN 150 29 2 7 pathname extensiOll 2 osse veter riter o ne ast a a eee ER eee ane aen eunte eR aan 150
18. 29 2 8 pathname replace directory eene eere eene teen tnnt etta edet eene nian 150 29 2 9 pathnamie replace tile rera eter rrr P he ERR ERR ERE gas EEEE SERERE tae 150 29 2 10 pathname replace CXteMSiON esecceececeseesseceeaeceeaceseneeceaceesaeceeaaeceeaeceeneeseaeessaecseaaeceaeeeeeeeess 151 29 2 1 pathname Strip GireCtOry iecur eret oet on ENEEIER E NEEE ESEESE 151 29 2 12 pathname strip extenslOn 4 eerie ener tet etn erint obese o aae rasa eot tne eae Ea dera get 151 20 3 Temporary Tiles serrer er REPORTER REESE OTRO ds deed 151 29 3 1 creat temporary file e eire ete lankicssaccasedsausaedguccesvaauausessancseuaencdadeseccectancese 151 29 4 Deleting a file without signalling an errot enne en teretes 151 20 2 e E E UE 151 29 5 Iterating over input lines and files sse eene enne enne nns nnn tenen nentes 151 29 5 1 Co eerie EE 152 IA TE 152 29 5 3 POEU TOT CACM sein TN 152 29 54 por E 152 29 6 Executing shell commands with formatstring and error checkug sess 152 DOO O EE 152 xlv CHICKEN User s Manual The User s Manual Chicken User s Manual 29 Unit utils ANGIE CN QO eT ATCA MAN BE 29 8 Miscellaneous handy E DOES E DOES TE EEN A A M SOM rei EE AER e EE E 30 3 tep reet is REOR ERRE EBERT UR ER IP digas ORE SENA ELTE EROR UNE RENTRER SS DOA tcp accept EE 30 5 tcp acceptzready EE MS i iie oi a e a iE pidaia 30 7 tcp listener fil ti
19. By default no output buffering for TCP output is done but to improve performance by minimizing the number of TCP packets buffering may be turned on by setting this parameter to an exact integer greater zero A buffer size of zero or f turns buffering off The setting of this parameter takes effect at the time when the I O ports for a particular socket are created i e when tcp connect or tcp accept is called Note that since output is not immediately written to the associated socket you may need to call flush output once you want the output to be transmitted Closing the output port will flush automatically 30 11 tcp abandon port 156 31 Example A very simple example follows Say we have the two files client scm and server scm client scm declare uses tcp define values i o tcp connect iocalhost 4242 write line Good Bye o print read line i server scm declare uses tcp define l tcp listen 4242 define values i o tcp accept 1 write line Hello o print read line i close input port i close output port o CSC server scm csc client scm o server amp s client Previous Unit utils Next Unit lolevel 31 Example 157 32 Unit lolevel This unit provides a number of handy low level operations Use at your own risk This unit uses the srfi 4 and extras units 32 1 Foreign pointers 32 1 1 address gt pointer procedure address gt pointer ADDRE
20. Line or none If BUFSIZE is specified it determines the size of the buffer to be used if any 28 20 Terminal ports 28 20 1 terminal name procedure terminal name PORT Returns the name of the terminal that is connected to PORT 28 20 2 terminal port procedure terminal port PORT Returns t if PORT is connected to a terminal and f otherwise 28 21 How Scheme procedures relate to UNIX C functions change directory chdir change file mode chmod change file owner chown create directory mkdir create fifo mkfifo create pipe pipe create session setsid 28 19 1 set buffering mode 142 CHICKEN User s Manual The User s Manual create symbolic link link current directory curdir current effective groupd id getegid current effective user id geteuid current group id getgid current parent id getppid current process id getpid current user id getuid delete directory rmdir duplicate fileno dup dup2 exit exit file close close file access time stat file change time stat file modification time stat file execute access access file open open 28 21 How Scheme procedures relate to UNIX C functions 143 CHICKEN User s Manual The User s Manual file lock fentl file position ftell lseek file read read file read access access file select select file control fentl file stat stat file test lock fentl file truncate
21. STRING Defines a foreign variable of name NAME a symbol STRING should be the real name of a foreign variable or parameterless macro If STRING is not given then the variable name NAME will be converted to a string and used instead All references and assignments via Set are modified to correctly convert values between Scheme and C representation This foreign variable can only be accessed in the current compilation unit but the name can be lexically shadowed Note that STRING can name an arbitrary C expression If no assignments are performed then STRING doesn t even have to specify an lvalue gt enum abc 3 def ghi lt define macro define simple foreign enum items begin G map match lambda name realname define foreign variable name int realname name define foreign variable name int items define simple foreign enum abc def ghi ghi gt 5 34 6 define foreign record syntax define foreign record NAME DECL SLOT Defines accessor procedures for a C structure definition NAME should either be a symbol or a list of the form TYPENAME FOREIGNNAME If NAME is a symbol then a C declaration will be generated that defines a C struct named struct NAME If NAME is a list then no struct declaration will be generated and FOREIGNNAME should name an existing C record type A foreign type specifier named NAME or TYPENAME will be defined as a pointer to the given C structure A S
22. SYMBOL Returns t if the global toplevel variable with the name SYMBOL is bound to a value or f otherwise 32 7 2 global ref procedure global ref SYMBOL Returns the value of the global variable SYMBOL If no variable under that name is bound an error is signalled Note that it is not possible to access a toplevel binding with global ref or global set if it has been hidden in compiled code via declare hide or if the code has been compiled in block mode 32 7 3 global set procedure global set SYMBOL X procedure set global ref SYMBOL X Sets the global variable named SYMBOL to the value X 32 8 Low level data access 32 8 1 block ref procedure block ref BLOCK INDEX Returns the contents of the INDEXth slot of the object BLOCK BLOCK may be a vector record structure pair or symbol 32 8 2 block set procedure block set BLOCK INDEX X procedure set block ref BLOCK INDEX X Sets the contents of the INDEXth slot of the object BLOCK to the value of X BLOCK may be a vector record structure pair or symbol 32 7 1 global bound 169 CHICKEN User s Manual The User s Manual 32 8 3 object copy procedure object copy X Copies X recursively and returns the fresh copy Objects allocated in static memory are copied back into garbage collected storage 32 8 4 make record instance procedure make record instance SYMBOL ARG1 Returns a new instance of the record typ
23. Sets the signal mask of the current process to block all signals given in the list SIGLIST Signals masked in that way will not be delivered to the current process 28 11 5 signal mask procedure signal mask Returns the signal mask of the current process 28 11 6 signal masked procedure signal masked SIGNUM Returns whether the signal for the code SIGNUM is currently masked 28 11 7 signal mask procedure signal mask SIGNUM Masks blocks the signal for the code SIGNUM 28 11 8 signal unmask procedure signal unmask SIGNUM Unmasks unblocks the signal for the code SIGNUM 28 11 9 signal term 28 11 3 signal handler 133 CHICKEN User s Manual The User s Manual 28 11 10 signal kill 28 11 11 signal int 28 11 12 signal hup 28 11 13 signal fpe 28 11 14 signal ill 28 11 15 signal segv 28 11 16 signal abrt 28 11 17 signal trap 28 11 18 signal quit 28 11 19 signal alrm 28 11 20 signal vtalrm 28 11 21 signal prof 28 11 22 signal io 28 11 10 signal kill 134 CHICKEN User s Manual The User s Manual 28 11 23 signal urg 28 11 24 signal chld 28 11 25 signal cont 28 11 26 signal stop 28 11 27 signal tstp 28 11 28 signal pipe 28 11 29 signal xcpu 28 11 30 signal xfsz 28 11 31 signal usr1 28 11 32 signal usr2 28 11 33 signal winch These variables contain signal codes for use with process signal set signal handler signal handLler signal mask
24. and warnings are enabled see enable warnings then a warning message is written to the port that is the value of current error port Blocking I O will block all threads except for some socket operations see the section about the tcp unit An exception is the read eval print loop on UNIX platforms waiting for input will not block other threads provided the current input port reads input from a console e It is generally not a good idea for one thread to call a continuation created by another thread if dynamic wind is involved e When more than one thread compete for the current time slice the thread that was waiting first will become the next runnable thread e The dynamic environment of a thread consists of the following state The current input output and error port The current exception handler 4 The values of all current parameters created by make parameter Any pending dynamic wind thunks The following procedures are provided in addition to the procedures defined in SRFI 18 27 1 thread signal procedure thread signal THREAD X This will cause THREAD to signal the condition X once it is scheduled for execution After signalling the condition the thread continues with its normal execution 27 2 thread quantum procedure thread quantum THREAD Returns the quantum of THREAD which is an exact integer specifying the approximate time slice of the thread in milliseconds 27 3 thread quantum set
25. declaration specifier not standard bindings SYMBOL 16 24 no bound checks 52 CHICKEN User s Manual The User s Manual Declares that all given standard procedures or all if no symbols are specified are never globally redefined If not is specified then all but the given standard bindings are assumed to be never redefined 16 31 extended bindings declaration specifier extended bindings SYMBOL declaration specifier not extended bindings SYMBOL Declares that all given non standard and CHICKEN specific procedures declaration specifier or all if no symbols are specified are never globally If not is specified then all but the given extended bindings are assumed to be never redefined 16 32 usual integrations declaration specifier usual integrations SYMBOL declaration specifier not usual integrations SYMBOL Declares that all given standard and extended bindings or all if no symbols are specified are never globally redefined If not is specified then all but the given standard and extended bindings are assumed to be never redefined Note that this is the default behaviour unless the no uSual integrations option has been given 16 33 unit declaration specifier unit SYMBOL Specify compilation unit name if this is a library 16 34 unsafe declaration specifier unsafe declaration specifier not safe Do not generate safety checks This is the same as specifying the un
26. define bar x gc x x define external baz int i double sqrt i return to host 37 10 CHICKEN apply to string 188 CHICKEN User s Manual The User s Manual 9 6 cat y c ZE El include lt chicken h gt include lt assert h gt extern double baz int int main 9 6 char buffer 256 int status C word val C SCHEME UNDEFINED C word data 1 data 0 amp vat CHICKEN run C toplevel status CHICKEN read bar 99 amp val assert status C gc protect data 1 printf data 08x n val status CHICKEN eval string to string bar buffer 255 assert status CHICKEN get error message buffer 255 printf ouch s n buffer status CHICKEN eval string to string bar 23 buffer 255 assert status printf gt s n buffer printf data 08x n val status CHICKEN eval to string val buffer 255 assert status printf gt s n buffer printf gt g n baz 22 return 0 csc x scm y c embedded Itis also possible to re enter the computation following the call to return to host by calling CHICKEN continue 37 14 CHICKEN yield 189 CHICKEN User s Manual The User s Manual 37 15 CHICKEN_continue C function C word CHICKEN continue C word k Re enters Scheme execution k is the continuation received from the previous invocation of CHICKEN run or CHICKEN continue When return to host is called aga
27. normally When multiple threads are running concurrently and control switches from one thread to another then the continuation of the current thread is captured and saved Any pending C stack frame still active from a callback will remain on the stack until the threads is re activated again This means that in a multithreading situation when C callbacks are involved the available nursery space can be smaller than expected So doing many nested SchemeCScheme calls can reduce the available memory up to the point of thrashing It is advisable to have only a single thread with pending C stack frames at any given time Pointers to Scheme data objects should not be stored in local or global variables while calling back to Scheme Any Scheme object not passed back to Scheme will be reclaimed or moved by the garbage collector Calls from C to Scheme are never tail recursive Continuations captured via Call with current continuation and passed to C code can be invoked like any other Scheme procedure Previous Other support procedures Next chicken setup 40 46 C post gc hook 204 41 chicken setup 41 1 Extension libraries Extension libraries eggs are extensions to the core functionality provided by the basic CHICKEN system to be built and installed separately The mechanism for loading compiled extensions is based on dynamically loadable code and as such is only available on systems on which loading compiled code at runtime is supported
28. procedure thread quantum set THREAD QUANTUM Sets the quantum of THREAD to QUANTUM 27 Unit srfi 18 113 CHICKEN User s Manual The User s Manual 27 4 thread suspend procedure thread suspend THREAD Suspends the execution of THREAD until resumed 27 5 thread resume procedure thread resume THREAD Readies the suspended thread THREAD 27 6 time gt milliseconds procedure time gt milliseconds TIME Converts a time object as created via current time into an exact integer representing the number of milliseconds since process startup 27 7 time gt milliseconds procedure time gt milliseconds TIME Converts a time object as created via current time into an exact integer representing the number of milliseconds since process startup Previous Unit regex Next Unit posix 27 4 thread suspend 114 28 Unit posix This unit provides services as used on many UNIX like systems Note that the following definitions are not all available on non UNIX systems like Windows See below for Windows specific notes This unit uses the regex scheduler extras and utils units All errors related to failing file operations will signal a condition of kind exn i o file 28 1 Directories 28 1 1 change directory procedure change directory NAME Changes the current working directory to NAME 28 1 2 current directory procedure current directory DIR Returns the name of the current
29. sasndacexnveagiarsnsegeasategsesaaeseeoaesedesossigs ves acid 105 IRSE SIA REN 105 22 24 SUD RA LTE 105 22 25 SUDTOAVECtOE rd ads 105 22 20 NA NN 106 RE EES 106 22 28 WELE S VECLOE veriti er REX ERE RR er rU EE EeeubU v C o aer E A belinda los evasion Ree Ee rase YR RUE 106 A Eo ree RU neers a 107 2 IEA UM 108 Si BI BT CN CG 109 O TO 110 DO O EE 110 PAID AGIT 110 DOWD TS RN 110 QO ATE SER 2 vases ME 110 26 5 SIN EE 111 ERR Een e E TE 111 26 7 Strinp SeatCh geed ce dees gedet ettet etai eee d e Eden os Lese lg ee eee deed 111 26 8 String Search DOSITIONS entente tenentes ER ESEESE tense a senes eE ror a 111 AS E RN 111 26 10 Eet E 112 26 1 ee e E s dieere ute duce ve ree dee e Peto Peta S on teddies vaidectuvedeatessavedesdsdednieesadavvwededs 112 26 12 O ea a v REQUE D RESI FI Re Pe HIR EE REN aspeced TUR GU HO Pape ads 112 1X CHICKEN User s Manual The User s Manual Chicken User s Manual A ROS RERO RE ER DR RHENO I P AO RN a M GM MEL DD 113 PB ue EE EE 113 21 2 thre NO 113 27 3 Re Ee E ht EE 113 27 4 thre ad SUS PSM E 114 A E 114 27 6 time mrlliseconds tr naci EE EENS ed 114 27 7 A EEN 114 SW E eee a eee 115 28 RRE 115 28 1 1 ch nge directory EE 115 28 1 2 current direCtOEy eee eege eege 115 205 1 3 create dIT CtOEy irruere ee Pede te ettet ree Pace oiie Plebe e H nee Pe er eiie 115 NEE 115 28 McD direct
30. 13 o procedure o PROC A single value version of compose slightly faster 0 is equivalent to identity 20 11 Binary searching 20 11 1 binary search procedure binary search SEQUENCE PROC Performs a binary search in SEQUENCE which should be a sorted list or vector PROC is called to compare items in the sequence should accept a single argument and return an exact integer zero if the searched value is equal to the current item negative if the searched value is less than the current item and positive otherwise Returns the index of the found value or f otherwise Previous Unit eval Next Unit srfi 1 20 10 10 project 101 21 Unit srfi 1 List library see the documentation for SRFI 1 Previous Unit extras Next Unit srfi 4 21 Unit srfi 1 102 22 Unit srfi 4 Homogeneous numeric vectors see the documentation for SRFI 4 64 bit integer vectors U64vector and s64vector are not supported The basic constructor procedures for number vectors are extended to allow allocating the storage in non garbage collected memory 22 1 make XXXvector procedure make XXXvector SIZE INIT NONGC FINALIZE Creates a SRFI 4 homogenous number vector of length SIZE If INIT is given it specifies the initial value for each slot in the vector The optional arguments NONGC and FINALIZE define whether the vector should be allocated in a memory area not subject to garbage collection and whether the associated storage should be
31. 130 LAIA ice citi tn eri anteire Le ettet te etai een PUE Tb deed ee PU Lay Hg eee e SEPTA xK evi eve etu 130 ER rte E 130 25 9 24 DEM OM DEENEN AER 130 2819 25 DELMAR OU RN 130 20 9 26 PETMAN WRU ege ee sted esas sg EC te dase VOU re dee EVE eatur e Peek dV Ee Fee ERE Eed ee ee 130 28 0 27 Perma WKS cercania iii aiii noia 130 28 9 28 perm ItWXQ RN 130 2B DDD A NN 130 LEAN EE 130 28 9 31 petm is gid O 130 28 9 32 EU dd 130 IRA e E 131 20 9 34 Set procesS STOUP IG E 131 ES Eu Ter O E 131 28 9 30 CLEALE SESSIOM Eed tas 131 28 10 Record NOK EE 131 28 10 1 file lock cccsccscsaseesscenvedcssvevvscdecensessvtecessssesussucenascovcevsuevetcdcsesvuadeaveesedsvuecuctoaceeseuvsveceseserdsventenss 131 28 102 file lock blockitig ctt e eerte tio EE RETE ti EE rr ER nadas 132 28 AOS Mile tes lO ESENTIUM Ee E 132 28 1 OA eii a 132 28 11 Signal handling ee reote rte tere i ride ete eee Eeer 132 286 11 BT EE e E 132 25 11 2 Set siPnal hamGler EE 132 28 1T 5 signal handl t 55 re tete at eee ne anas e ese RR Nn 133 GEREENT 133 28 V1 2 sigil Mask A pabbenaeaeaunteonteseaaaeas 133 25 11 6 signal mask d eege ii id 133 28 11 stonal mask cartoons iiatda 133 e EE KEE 133 RENE 133 28 1110 EE EE 134 2G MA ER EE LTE 134 LN A EE 134 28 11 13 ONO 134 SS TE Leena cias 134 E EE LE 134 26 11 16 Signal abrt uo erre ive e ee deer e eet Vaess wan teddies ee INVI dean eode ed eee ESE 134 SR RTE LE 134 GR EE LE LU EE 134
32. 18 1 20 fx lt 18 1 21 fx gt 18 1 22 fx lt 18 1 23 fxand 18 1 24 fxior 18 1 25 fxxor 18 1 26 fxnot 18 1 27 fxshl 18 1 28 fxshr procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure procedure 18 1 19 fx gt fx N1 N2 fxmod N1 N2 fxneg N fxmin N1 N2 fxmax N1 N2 fx N1 N2 fx gt N1 N2 fx lt N1 N2 fx gt N1 N2 fx lt N1 N2 fxand N1 N2 fxior N1 N2 fxxor N1 N2 fxnot N 60 CHICKEN User s Manual The User s Manual procedure fxshl N1 N2 procedure fxshr N1 N2 Arithmetic fixnum operations These procedures do not check their arguments so non fixnum parameters will result in incorrect results fxneg negates its argument On division by zero fx and f xmod signal a condition of kind exn arithmetic fxshl and fxshr perform arithmetic shift left and right respectively 18 1 29 flonum 18 1 30 fp 18 1 31 fp 18 1 32 fp 18 1 33 fp 18 1 34 fpneg 18 1 35 fpmin 18 1 36 fpmax 18 1 37 fp 18 1 38 fp gt 18 1 28 fxshr 61 CHICKEN User s Manual The User s Manual 18 1 39 fp lt 18 1 40 fp gt 18 1 41 fp lt procedure flonum X procedure fp X Y procedure fp X Y procedure fp X Y procedure fp X Y procedure fpneg X procedure fpmin X
33. 26 nonnull pointer TYPE nonnull c pointer TEE 183 35 27 PER TYPE Joeraren T T 183 35 28 Strict NAME RT iaa dis 183 39 29 template TYPE ARGTYPE E eeniceeteetceet cet eoe te edd eue a ens een eden eode lod ero ata 183 35 30 union E EE 183 35 31 instance CNAME SCHEMECT ASS 184 35 32 Opnstance refCNAMESCHEMECL ASS 184 35 33 function RESULTTYPE ARGUMENTTYPE1 CALLCONY mA 184 30 Npp E TE 185 REB OUTPUT T 186 37 1 CHICKEN parse command ne 186 37 2 CHICKEN guer A ie Ee ERE ee ab vC 186 ILISICHICKEN EE 186 SA e ee Eeer GE Ee 187 37 gt CHICKEN Uat tail idea deranged 187 ARTO ILEANA TON 187 37 CHICKEN val to SNS iier ether eee tee ge eet E E eege Aisa 187 37 8 CHICKEN eval string to stong 187 ILO CHICKEN appl C 187 37 10 CHICKEN apply t String EE 188 SAA E CHICKEN Tide 188 31 12 CHICKEN O EE 188 37 13 CHICKEN get error MESSAGES seiere preti Dreti D Eear ri ete SEES OE D EREE nad dS 188 ITA CHICKEN yield EE 188 SEBES IL E EH 190 37 16 CHICKEN new TE 191 37 17 CHICKEN delete E 191 37 18 CHICKEN gc TE eene ta leia 191 37 19 CHICKEN 9C TOOL S60 RNA 191 37 20 CHICKEN lobal lookip eu g rre etn ter net ee rhe rera eene Ee ENEE 191 RECH RSC US SECHER E 191 37 22 CHICKEN global set on dtr erre aep ttu I et Ee Eo ERR eR Pese 192 EnEE ELM e RR m ds 193 38 11 deline RE
34. 2AY2A776ddT40S30SnMVCOOVVORRR45E42063 rNz amp v 7UX amp U0ZF F J amp 44ETCnVn a amp 1CDN Y amp OM V1c amp j2AYdjmMdjjd o amp lr M T 0 4 3 r put T g T 9 g cvn cvi J g I I cvx forall moveto p floor w div S add 29 H setgray fill for Y for showpage EOF 28 3 Fifos 28 3 1 create fifo procedure create fifo FILENAME MODE Creates a FIFO with the name FILENAME and the permission bits MODE which defaults to procedure perm irwxu perm irwxg perm irwxo 28 3 2 fifo procedure fifo FILENAME Returns t if the file with the name FILENAME names a FIFO 28 4 File descriptors and low level I O 28 4 1 duplicate fileno procedure duplicate fileno OLD NEW If NEW is given then the file descriptor NEW is opened to access the file with the file descriptor OLD Otherwise a fresh file descriptor accessing the same file as OLD is returned 28 2 10 with output to pipe 118 CHICKEN User s Manual The User s Manual 28 4 2 file close procedure file close FILENO Closes the input output file with the file descriptor FILENO 28 4 3 file open procedure file open FILENAME FLAGS MODE Opens the file specified with the string FILENAME and open flags FLAGS using the C function open On success a file descriptor for the opened file is returned FLAGS should be a bitmask containing one or more of the open values ored together using bitwise ior or simply added together The optional MODE s
35. 33 set group id procedure set group id GID setter set current group id GID Sets the effective group id of the current process to GID which should be a positive integer 28 9 34 set process group id procedure set process group id PID PGID setter set process group id PID PGID Sets the process group ID of the process specifed by PID to PGID 28 9 35 user information procedure user information USER If USER specifes a valid username as a string or user ID then the user database is consulted and a list of 7 values are returned the user name the encrypted password the user ID the group ID a user specific string the home directory and the default shell If no user with this name or ID can be found then f is returned 28 9 36 create session procedure create session Creates a new session if the calling process is not a process group leader and returns the session ID 28 10 Record locking 28 10 1 file lock procedure file lock PORT START LEN Locks the file associated with PORT for reading or writing according to whether PORT is an input or output port START specifies the starting position in the file to be locked and defaults to O LEN specifies the length of the portion to be locked and defaults to t which means the complete file File Lock returns a lock object 28 9 32 set user id 131 CHICKEN User s Manual The User s Manual 28 10 2 file lock blocking procedure
36. 44 Introduction This is the list of Frequently Asked Questions about Chicken Scheme If you have a question not answered here feel free to post to the chicken users mailing list if you consider your question general enough feel free to add it to this list 44 Introduction 221 45 General 45 1 Why yet another Scheme implementation Since Scheme is a relatively simple language a large number of implementations exist and each has its specific advantages and disadvantages Some are fast some provide a rich programming environment Some are free others are tailored to specific domains and so on The reasons for the existence of CHICKEN are e CHICKEN is portable because it generates C code that runs on a large number of platforms e CHICKEN is extendable since its code generation scheme and runtime system garbage collector fits neatly into a C environment e CHICKEN is free and can be freely distributed including its source code e CHICKEN offers better performance than nearly all interpreter based implementations but still provides full Scheme semantics e As far as we know CHICKEN is the first implementation of Scheme that uses Henry Baker s Cheney on the M T A concept 45 2 What should do if find a bug Send e mail to felix call with current continuation org with some hints about the problem like version build of the compiler platform system configuration code that causes the bug etc 45 3 Why are values defined w
37. 64 EPA NN 64 LOUIS econo A ah 64 18 5 Feat re AAN NEE voe EXE x va ken EEN Age d 65 18 5 1 f6atUtes E 65 18 5 2 E 65 ARA edic RP M 65 Ee EE ER 65 18 6 ROY O 65 18 6 T SCt KEY EE 66 IA XA L MP 66 ARENAS EE 66 LARA A RN 66 187 Ee lee EE 66 18 7 1 Condition CaSe riales bas 66 18 7 2 breakpotnt iae reete ett e denke ten vers Pede duda ete UHR EEN deen 67 18 8 Environment information and system Interface 68 IEN WE 68 ERA A NS 68 18 8 3 build Ee E 69 18 94 chicken VEO Aaa aia dea 69 RN NN 69 RA RAN 69 RARAS CN AA O 69 18 8 5 O 70 EA EE 70 18 8 LO SOT WATE CV DG eret ree A AA A AAA AR AA AAA A 70 ISS Ulsoftware vergion no nano tenete nn nono n nro nono eiiiai 70 18 8 12 C T lttffie EE 71 15 8 13 SyStem E 71 Kee rer ae 71 LAN RN 71 RE e ee Ee EE 71 18 9 5 current seconds i ettet A A ies 71 ERA EE 72 18 10 Interrupts and error handling ierit tenete rr rante ee rhe tutti dl ente Ped ee eee eee edu 72 CAMARENA oeei E E ES E E EE E TRE EEE EE EEE EN 72 18 VO 2V EE 72 EA ROS 72 18 104 erte Ee Et E 72 18 10 35 print ert r NO 73 18 10 6 procedure informatiOn NN 73 TEMO SIS EET TT DT 73 CHICKEN User s Manual The User s Manual Chicken User s Manual 18 Unit library E TEE 73 18 10 99 O 73 18 11 Garbage come ct e 73 eerste 73 15 11 2 memoty StatistICs AAA eerte teinte ener etre oie tle a ehe e edere ede ete e
38. 89 20 3 Formatted Be EE 90 DONADO E 90 QO A e EE EE 91 20 5 QUEUES iii ita 91 PA NEU 91 20 5 2 MAKE EE 91 20 53 TT 91 20 54 A EE 92 20 5 5 ON 92 IN A AS 92 AI EE 92 20 5 8 EE dadas 92 AAN EE 92 20 510 QUEUE Ee 92 vii CHICKEN User s Manual The User s Manual Chicken User s Manual 20 Unit extras O NO A Mert EEN SARL WE ee NN 1 MOE MSOs ee E ee Ee 1 20 11 A sted doveaetantuateconadaausacensaiveed uedeadencacesivdevasasaans 1 A steen NA 1 CHICKEN User s Manual The User s Manual Chicken User s Manual A BE 102 PAN BE 1 E D 103 22 1 make X EEN 103 22 2USVECLOL gt DYLE VECLOR E 103 22 3 EE EE EE 103 22 4 UWI GVECtOT gt DVLE VECIOL nee eere rer shies ssvhagaucetence MER ERREUR as SEENEN EE aes 103 22 5 sl Ovector gt DYte Veco iii iia Ed Due edge 103 IRA A O d 103 ISI E E 103 22 8 EE Ee 103 22 0 TOAVECLOT SDVLE VECION EE 104 22 10 byte Vector uSVectotr c cese terere en ee EE laa 104 22 11 byte VeCtOr gt s E VOCLOE iieri iter rre rettet eege Eden de HU eene e P EP oda Reden 104 22 12 byte vector ulOVectot ee aeree cecnadcdosndeas EEE EFERRE ARTI ERE TERR SETA NEAREST A RTe ties 104 22 13 byt v ctor s16vector 5 pedet reto dee ede AEN 104 IO A M 104 22 E ENT E 104 22 16 DYLE VECLOT EE 104 22 17 Dyte v ctor TOA EE 104 22 NS SUDUS ECO ii D NUM 105 22 19 SUDUT e EE 105 ET E IT RA LE 105 22 2ASUDSSVECIOT EE 105 22 22 SUDSLOVECUOL isav
39. Block Comment 27 13 2 Expression Comment A TN 27 13 3 External DE ET 27 13 4 Syntax E Te E 27 13 3 Location EXDTESSION cer ii A A ld dei 27 EAT RNA 27 ENANA eterne entes EEEE EEEE tense tnter innen 28 13 8 Multiline String Constant with Embedded Exvpresetonz essere 28 13 9 Foreign AOS 28 13 10 Sharp Prefixed SymboL e ere ete er rete ette er iinei eae erg a ao ed 28 IERBB IET 29 13 11 1 Ene Cot iia 29 13 112 HOt ODE E 29 CHICKEN User s Manual The User s Manual Chicken User s Manual 13 Non standard read syntax 13 11 3 DSSSL Formal Parameter List Annotaton esee nennen 29 13 11 4 Read Mark Invocation 1 nieeciicee ec cerrar a aE AEN d e nadaa 29 13 12 Case Sensitive EXpressiOfn oce decere O Uv HR odes 29 13 13 Case Insensitive TT onere entree eto eo er O eese eeu Neon eod aee euet E e 29 ENS ADS A i ii inie esai esiaine koen oiinanauian 30 14 Non standard macros and special a A e i 31 14 1 Making extra libraries and extensions available 31 ES EE EE 31 14 1 2 EE 32 14 2 Binding forms for optional arguments esses enne enne tenente nnns tennis nere nen rennen 32 EA aare e e E EEEE EAE E E T E E EEE O S 33 H o er emi AMIGA EENEG 33 14 2 3 let le 33 E WE ele E EE 33 14 3 Other binding rer EE 34 ER tand A cen eet esee e tee e PLU e METER 34 IC NIA GE 34 I
40. CHICKEN User s Manual The User s Manual user information getpwnam getpwuid utc time gt seconds timegm 28 22 Windows specific notes The following definitions are not supported for native Windows builds compiled with the Microsoft tools or with MingW open noctty open nonblock open fsync open sync perm isvtx perm isuid perm isgid file select file control Signal except signal term signal int signal fpe signal ill signal segv set signal mask signal mask signal masked signal mask signal unmask user information group information get groups set groups initialize groups errno wouldblock Change file owner current user id current group id current effective user id current effective set user id set group id create session process group id set process group id create symbolic link read symbolic link file truncate file lock file lock blocking file unlock file test lock create fifo fifo prot map map file to memory unmap file from memory memory mapped file pointer memory set alarm terminal port terminal name process fork process signal parent process id set root directory utc time gt seconds local timezone abbreviation Additionally the following definitions are only available for Windows 28 22 1 spawn overlay 28 22 2 spawn wait 28 22 Windows specific notes 147 CHICKEN User s Manual The User s Manual 28 22 3 spawn nowait 28 22 4 spawn nowaito 28 22 5 spawn detach
41. Currently these are most UNIX compatible platforms that provide the Libdl functionality like Linux Solaris BSD Mac OS X and Windows using Cygwin Note Extension may also be normal applications or shell scripts but are usually libraries chicken setup will download the source code for extension automatically from the canonical server at http www call with current continuation org eggs if the requested egg does not exist in the current directory Various command line options exist for customizing the process and or retrieving the egg from other locations or in other formats 41 2 Installing extensions To install an extension library run the chicken setup program with the extension name as argument The extension archive is downloaded its contents extracted and the contained setup script is executed This setup script is a normal Scheme source file which will be interpreted by chicken setup The complete language supported by CS1 is available and the library units srfi 1 regex utils posix tcp are loaded Additional libraries can be loaded at run time The setup script should perform all necessary steps to build the new library or application After a successful build the extension can be installed by invoking one of the procedures install extension install programorinstall script These procedures will copy a number of given files into the extension repository or in the path where the CHICKEN executables are located in the case of e
42. E DN Er 163 32 3 2 Oxtended procedure EE 163 D2 323 A 163 SE E EE E 163 32 4 ENEE E 164 SE Be E EE 164 32 4 2 Ee E 164 32 4 3 byt v ctor TM ME 164 32 44 EE TE E 164 32 4 5 EE TE RE 164 ARANA EC 165 32 4 7 byte VectOr Tet EE 165 32 4 8 EE TEE 165 324 9 Tist Dyte Vectot EE 165 32 4 10 make byte Vectot cores testet en n tos ne reete bores li aaa 165 32 4 11 make stane hvte vectgt eene enne enne enne ene tensis nnne cnn trennen 165 AAA O entente enne ennt EEEE SS 166 32 4 13 String byte v ctot ie etr tette epe doctr ica e ES ee aiii 166 32 5 Data 1mm unmanaged MEMO retreat EY REX Ee SER SHE o Pee gh ERR SEE NE RE REN ERREUR TX ERAS SERRE AED ETEISEEN SNE 166 SRA TORO TOO 166 32 5 2 Oe De e 166 E ENT EE RE 167 D2 DAD ICC Le SIZE eege eer ee e 167 SS A AT 167 32 5 6 Object ET E 167 SE EE EE Lat ee 167 SAN EE 167 32 6 2 MAK E WEAK OCALIVE Jis er erected eto o oe eu o deo nuo Eo eu xv E sus sso e ARR VR VR n E Ru DEENEN 168 32 0 3 ee 168 32 6 4 ISP TESI 168 32 6 5 e 168 32 6 6 A n seriinisoisn tieien iiaeie oi an esee aia ii niaan 168 32 7 Accessing TER E 168 32 1 1 ee Ee e KEE 169 EE RN 169 SAP ertet ETE endi e tere Pedo dea desu de Feo uu ea dne ede tue Eee aa eee euo dean 169 32 5 L owslevel EE 169 32 8 1 ee RE 169 ee 169 32 8 3 0D e Gt CODN sessirnir ride tese rr e rettet etai eee ie ia eee bs esee lg ee eee dee ee 170 E E AO NEE ET EE 170 32 8 5 MIOVE MEMOLY EE 1
43. Ene ERE eee E UV VE ac eua 125 PERRA Uu a 125 26 7 6 DrOcess Sig tial s deene dee tet ve dee er eeu e ae Eneas ean test eee inr AEE aee dee 125 QB TT e EE 125 A NEE 125 2B PD PLOCESS MN IEEE 126 PN ES E 126 28 8 Hatd and symbolic links oie or ri eer ORE T HR ERE E SERRE EP RR E Pe EMEN EE ends 126 25 8 1 symbolic link 2 BI onde det eee ep eds tes eios E heed ae 126 28 8 2 create Symbolic link etecro cresta nee onto eR SEES ek eee EE ERR URP ER EN kee gege euer 126 28 5 3 read symbolic Tink A ente tee reed dead esu e sade ane rada eene bet aa eee aged 127 Ee RTT TIL 127 2879 RIESCO ii TETTE LIUM 127 28 9 1 e SEIEN 127 Ee TE 127 28 9 3 Ee 127 28 94 file Write ACCESS a ici 127 28 9 5 EE EE LEE 127 RENE EE TE 128 28 0 7 EI EE 128 28 9 8 CUITEMER USET 10 EEN 128 25 9 0 current PrOUD Id a A Urea tub de AA A A EA 128 xi CHICKEN User s Manual The User s Manual Chicken User s Manual 28 Unit posix 28 9 10 current effective USCr IO occcccccccccnccnnnnccnonincncncncanacanananananana no nono nono serina nono ono no nononononocacananenos 128 28 9 11 current effective GrOUP 1 2 eecceecceeecesseecessecesaeececececeecsueeeaaecseaceceaceceeeesaeeseaaecseaeeeeaeeseaees 128 28 9 12 PrOCeSS STOUP 1 ME 128 25 9 13 OUNAE e 129 GENEE EE 129 25 0 15 set E 129 RE EE ACIER 129 28 9 17 EE 129 28 9 ER 01 PALA AE AEA E T 129 ARA RO 129 25 9 20 perm itgrp EE 130 28 9 21 A E
44. FILENAME Executes the given Scheme source file with all remaining arguments and exit The she bang shell script header is recognized so you can write Scheme scripts that use chicken setup just as with CS1 e eval EXPRESSION Evaluates the given expression s v verbose Display additional debug information k keep Keep temporary files and directories 41 6 chicken setup reference 214 CHICKEN User s Manual The User s Manual c csc option OPTION Passes OPTION as an extra argument to invocations of the compiler driver CSC This works only if CSC is invoked as run csc d dont ask Do not ask the user before trying to download required extensions n no install Do not install generated binaries and or support files Any invocations of install progranm install extension or install script will be be no ops i docindex Displays the path to the index page of any installed extension documentation If the index page does not exist it is created C check Downloads the repository index and lists locally installed extensions for which a newer release is available for download t test EXTENSION return success if all given extensions are installed ls EXTENSION List installed files for extension fetch tree Download and print the repository catalog tree FILENAME Download and show the repository catalog svn URL Fetch extension from Subversion repository revision REV Specifies SVN revision to check out Local P
45. In composite conditionss all properties are currently collected in a single property list so in the case that to conditions have the same named property only one will be visible 18 8 Environment information and system interface 18 8 1 argv procedure argv Return a list of all supplied command line arguments The first item in the list is a string containing the name of the executing program The other items are the arguments passed to the application This list is freshly created on every invocation of argv It depends on the host shell whether arguments are expanded Cglobbed or not 18 8 2 exit procedure exit CODE Exit the running process and return exit code which defaults to 0 Invokes exit handler 18 7 2 breakpoint 68 CHICKEN User s Manual The User s Manual 18 8 3 build platform procedure build platform Returns a symbol specifying the toolset which has been used for building the executing system which is one of the following cygwin msvc mingw32 gnu metrowerks intel watcom unknown 18 8 4 chicken version procedure chicken version FULL Returns a string containing the version number of the CHICKEN runtime system If the optional argument FULL is given and true then a full version string is returned 18 8 5 errno procedure errno Returns the error code of the last system call 18 8 6 getenv procedure getenv STRING Returns the value of the environment variable
46. These variables contains special flags that specify the exact semantics of process spawn spawn overlay replaces the current process with the new one Spawn wait suspends execution of the current process until the spawned process returns spawn nowait does the opposite spawn nowaito is identical according to the Microsoft documentation and runs the process asynchronously spawn detach runs the new process in the background without being attached to a console 28 22 6 process spawn procedure process spawn MODE FILENAME ARGUMENT Creates and runs a new process with the given filename and command line arguments MODE specifies how exactly the process should be executed and must be one or more of the spawn flags defined above Previous Unit srfi 18 Next Unit utils 28 22 3 spawn nowait 148 29 Unit utils This unit contains file pathname oriented procedures apropos plus acts as a grab bag for procedures without a good home and which don t have to be available by default as compared to the extras unit This unit uses the extras and regex units 29 1 Environment Query 29 1 1 apropos procedure apropos SYMBOL PATTERN ENVIRONMENT Displays symbols matching SYMBOL PATTERN in the ENVIRONMENT on the current output port SYMBOL PATTERN A symbol string or regex When symbol or string substring matching is performed ENVIRONMENT An environment When missing the interaction environment is assumed
47. Tue May 21 13 46 22 1991 n 28 14 2 local time gt seconds 138 CHICKEN User s Manual The User s Manual 28 15 Raw exit 28 15 1 exit procedure exit CODE Exits the current process without flushing any buffered output using the C function exit Note that the exit handLler is not called when this procedure is invoked The optional return code CODE defaults to 28 16 ERRNO values 28 16 1 errno perm 28 16 2 errno noent 28 16 3 errno srch 28 16 4 errno intr 28 16 5 errno io 28 16 6 errno noexec 28 16 7 errno badf 28 16 8 errno child 28 16 9 errno nomem 28 15 Raw exit 0 139 CHICKEN User s Manual The User s Manual 28 16 10 errno acces 28 16 11 errno fault 28 16 12 errno busy 28 16 13 errno notdir 28 16 14 errno isdir 28 16 15 errno inval 28 16 16 errno mfile 28 16 17 errno nospc 28 16 18 errno spipe 28 16 19 errno pipe 28 16 20 errno again 28 16 21 errno rofs 28 16 22 errno exist 28 16 10 errno acces 140 CHICKEN User s Manual The User s Manual 28 16 23 errno wouldblock These variables contain error codes as returned by errno 28 17 Finding files 28 17 1 find files procedure find files DIRECTORY PREDICATE ACTION IDENTITY LIMIT Recursively traverses the contents of DIRECTORY which should be a string and invokes the procedure ACTION for all files for which the procedure PREDICATE is true PREDICATE may me a procedure of one argument
48. allocation pointer created with C alloc 40 19 C alloc C macro C word C alloc int words Allocates memory from the C stack C al Loc and returns a pointer to it words should be the number of words needed for all data objects that are to be created in this function Note that stack allocated data objects have to be passed to Scheme callback functions or they will not be seen by the garbage collector This is really only usable for callback procedure invocations make sure not to use it in normal code because the allocated memory will be re used after the foreign procedure returns When invoking Scheme callback procedures a minor garbage collection is performed so data allocated with C alloc will already have moved to a safe place Note that C alloc is really just a wrapper around al loca and can also be simulated by declaring a stack allocated array of C words 40 20 C SIZEOF LIST C macro int C SIZEOF LIST int length 40 24 C SIZEOF STRING C macro int C SIZEOF STRING int Length 40 22 C SIZEOF VECTOR C macro int C SIZEOF VECTOR int Length 40 17 C vector 199 CHICKEN User s Manual The User s Manual 40 23 C_SIZEOF_INTERNED SYMBOL C macro int C SIZEOF INTERNED SYMBOL int length 40 24 C SIZEOF PAIR C macro int C SIZEOF PAIR 40 25 C SIZEOF FLONUM C macro int C SIZEOF FLONUM 40 26 C SIZEOF POINTER C macro int C SIZEOF POINTER 40 27 C SIZEOF LOCATIVE C macro int C SIZEOF LOCATIVE 40 28 C SI
49. automatically freed using finalization when there are no references from Scheme variables and data NONGC defaults to f the vector will be located in normal garbage collected memory and FINALIZE defaults to t Note that the FINALIZE argument is only used when NONGC is true Additionally the following procedures are provided 22 2 u8vector gt byte vector 22 3 s8vector gt byte vector 22 4 u16vector gt byte vector 22 5 s16vector gt byte vector 22 6 u32vector gt byte vector 22 7 s32vector gt byte vector 22 8 f32vector gt byte vector 22 Unit srfi 4 103 CHICKEN User s Manual The User s Manual 22 9 f64vector gt byte vector procedure u8vector gt byte vector U8VECTOR procedure s8vector gt byte vector S8VECTOR procedure ul6vector gt byte vector U16VECTOR procedure sl6vector gt byte vector S16VECTOR procedure u32vector gt byte vector U32VECTOR procedure s32vector gt byte vector S32VECTOR procedure f32vector gt byte vector F32VECTOR procedure f64vector gt byte vector F64VECTOR Each of these procedures return the contents of the given vector as a packed byte vector The byte order in that vector is platform dependent for example little endian on an Intel processor The returned byte vector shares memory with the contents of the vector 22 10 byte vector gt u8vector 22 11 byte vector gt s8vector 22 12 byte vector gt u16vector 22 13 byte vector gt s16vector
50. char code 40 5 C SCHEME END OF LIST C macro C SCHEME END OF LIST 40 6 C word C SCHEME END OF FILE C macro C SCHEME END OF FILE 40 7 C word C SCHEME FALSE C macro C SCHEME FALSE 40 C interface 197 CHICKEN User s Manual The User s Manual 40 8 C word C SCHEME TRUE C macro C SCHEME TRUE These macros return immediate Scheme data objects 40 9 C string C function C word 40 10 C string2 C function C word 40 11 C intern2 C function C word 40 12 C intern3 C function C word 40 13 C pair C function C word 40 14 C flonum C function C word C string C word ptr int length char string C string2 C word ptr char zero terminated string C intern2 C word ptr char zero terminated string C intern3 C word ptr char zero terminated string C wo C pair C word ptr C word car C word cdr C flonum C word ptr double number 40 15 C int to num C function C word 40 16 C mpointer C function C word C int to num C word ptr int integer C mpointer C word ptr void pointer 40 8 C word C SCHEME TRUE 198 CHICKEN User s Manual The User s Manual 40 17 C_vector C function C word C vector C word ptr int length 40 18 C list C function C word C list C word ptr int length These functions allocate memory from pt r and initialize a fresh data object The new data object is returned ptr should be the address of an
51. chicken on UNIX systems 19 4 2 extension information procedure extension information ID If an extension with the name ID is installed and if it has a setup information list registered in the extension repository then the info list is returned Otherwise extension information returns f 19 4 3 provide procedure provide ID Registers the extension IDs ID as loaded This is mainly intended to provide aliases for certain extension identifiers 19 4 4 provided procedure provided ID Returns t if the extension with the IDs ID are currently loaded or f otherwise 19 3 6 syntax error 84 CHICKEN User s Manual The User s Manual 19 4 5 require procedure require ID procedure require for syntax ID If the extension library ID is not already loaded into the system then require will lookup the location of the shared extension library and load it If ID names a library unit of the base system then it is loaded via load library If no extension library is available for the given ID then an attempt is made to load the file ID so or ID scm in that order from one of the following locations e the current include path which defaults to the pathnames given in CHICKEN INCLUDE PATH and CHICKEN HOME e the current directory ID should be a string or a symbol The difference between require and require for syntax is the the latter loads the extension library at compile time the argume
52. compile time whether the extension named ID is installed and whether its version is equal or higher than NUMBER NUMBER may be a string or a number the comparison is done lexicographically using st ring gt See also set extension specifier 14 1 2 define extension syntax define extension NAME CLAUSE This macro simplifies the task of writing extensions that can be linked both statically and dynamically If encountered in interpreted code or code that is compiled into a shared object specifically if compiled with the feature chicken compi le shared done automatically by CSC when compiling with the shared or dynamic option then the code given by clauses of the form dynamic EXPRESSION are inserted into the output as a begin form If compiled statically specifically if the feature chicken compi led shared has not been given then this form expands into the following declare unit NAME provide NAME and all clauses of the form static EXPRESSION all additionally inserted into the expansion As aconvenience the clause export IDENTIFIER is also allowed and is identical to declare export IDENTIFIER unless the define extension form occurs in interpreted code in with it is simply ignored Note that the compiler option extension NAME is equivalent to prefixing the compiled file with define extension NAME 14 2 Binding forms for optional arguments 14 1 1 require extens
53. defined character names are supported See char name Characters can be given in hexadecimal notation using the AxXX syntax where XX specifies the character code Character codes above 12 Extensions to the standard 25 CHICKEN User s Manual The User s Manual 255 are supported and can be read and are written using the AuXXXX and AUXXXXXXXX notations Non standard characters names supported are tab Linefeed return alarm vtab nul page esc delete and backspace 6 3 5 CHICKEN supports special characters preceded with a backslash in quoted string constants V denotes the newline character V carriage return V backspace V TAB V vertical TAB Va alarm V formfeed WXX a character with the code XX in hex and WXXXX and UXXXXXXXX a unicode character with the code XXXX The latter is encoded in UTF 8 format The third argument to subst ring is optional and defaults to the length of the string 6 4 force called with an argument that is not a promise returns that object unchanged Captured continuations can be safely invoked inside before and after thunks of a dynamic wind form and execute in the outer dynamic context of the dynamic wind form Implicit non multival continuations accept multiple values by discarding all but the first result Zero values result in the continuation receiving an unspecified value Note that this slight relaxation of the behaviour of returning mulitple values to non multival cont
54. dots ie or two dots and an non negative integer eg 1 2 or three consecutive underscores ie L or two underscores and a non negative integer The keywords K and k are equivalent The keywords 0 and 0 are equivalent The next subsection describes the various patterns The match Lambda and match Lambda forms are convenient combinations of mat ch and Lambda and can be explained as follows match lambda pat body match lambda pat body Lambda x match x pat body Lambda x match x pat body where X is a unique variable The match Lambda form is convenient when defining a single argument function that immediately destructures its argument The mat ch Lambda form constructs a function that 15 1 Pattern Matching Expressions 43 CHICKEN User s Manual The User s Manual accepts any number of arguments the patterns of match Lambda should be lists The match let match Let match Letrec and match define forms generalize Scheme s Let let Letrec and define expressions to allow patterns in the binding position rather than just variables For example the following expression match let x y z list 1 2 3 body binds X to 1 y to 2 and Z to 3 in body These forms are convenient for destructuring the result of a function that returns multiple values as a list or vector As usual for Let rec and define pattern variables bound by match let
55. enum TYPENAME ITEM Defines a foreign type as with define foreign type that maps the elements of a C C enum or a enum like list of constants to and from a set of symbols TYPENAME names a foreign type that converts a symbol argument from the set ITEM into the appropriate enum value when passed as an argument to a foreign function A list of symbols passed as an argument will be combined using bitwise ior An empty list will be passed as 0 zero Results of the enum type are automatically converted into a symbol note that combinations are not supported in this case TYPENAME may alternatively be a list of the form SCHEMENAME REALTYPE in this case REALTYPE designates the native type used The default native type is TYPENAME Additionally two procedures are generated named SCHEMENAME number and number gt SCHEMENAME which take one argument and convert a symbol or a list of symbols into its numeric value and vice versa Here a heavily contrived example gt enum foo a foo 4 b foo c foo enum foo bar enum foo x printf d n x return b foo lt define foreign enum foo enum foo a foo b foo c c foo 34 6 5 rename 177 CHICKEN User s Manual The User s Manual define bar foreign lambda foo bar foo pp bar pp bar a foo pp bar b foo c 34 8 foreign lambda syntax foreign lambda RETURNTYPE NAME ARGTYPE Represents a binding to an external routine This fo
56. extension translation for the file list but does currently not do that for the Static extension property To actually link with the static version of my ext do csc static extensions my program scm uses my ext The compiler will try to do the right thing but can not handle all extensions since the ability to statically link eggs is relatively new Eggs that support static linking are designated as being able to do so If you require a statically linkable version of an egg that has not been converted yet contact the extension author or the CHICKEN mailing list Previous Interface to external functions and variables Next Data representation 41 10 Linking extensions statically 217 42 Data Representation Note In all cases below bits are numbered starting at 1 and beginning with the lowest order bit There exist two different kinds of data objects in the CHICKEN system immediate and non immediate objects Immediate objects are represented by a single machine word which is usually of 32 bits length or 64 bits on 64 bit architectures The immediate objects come in four different flavors fixnums that is small exact integers where bit 1 is set to 1 This gives fixnums a range of 31 bits for the actual numeric value 63 bits on 64 bit architectures characters where bits 1 4 are equal to C CHARACTER BITS The Unicode code point of the character is encoded in bits 9 to 32 booleans where bits 1 4 are equal to C BOOLEAN
57. gives the offset of the section of the file to be mapped and defaults to 0 This procedure returns an object representing the mapped file section The procedure move memo ry can be used to access the mapped memory 28 12 1 current environment 136 CHICKEN User s Manual The User s Manual 28 13 3 memory mapped file pointer procedure memory mapped file pointer MMAP Returns a machine pointer to the start of the memory region to which the file is mapped 28 13 4 unmap file from memory procedure unmap file from memory MMAP LEN Unmaps the section of a file mapped to memory using the C function munmap MMAP should be a mapped file as returned by the procedure map file to memory The optional argument LEN specifies the length of the section to be unmapped and defaults to the complete length given when the file was mapped 28 14 Date and time routines 28 14 1 seconds gt local time procedure seconds gt local time SECONDS Breaks down the time value represented in SECONDS into a 10 element vector of the form seconds minutes hours mday month year wday yday dstflag timezone in the following format seconds 0 the number of seconds after the minute 0 59 minutes 1 the number of minutes after the hour 0 59 hours 2 the number of hours past midnight 0 23 mday 3 the day of the month 1 31 month 4 the number of months since january 0 11 year 5 the number of years since 1900 wday 6
58. int or with 32 64 bit width 35 8 long unsigned long Either a fixnum or a flonum in the range of a unsigned machine Jong or with 32 bit width 35 Foreign type specifiers 180 CHICKEN User s Manual The User s Manual 35 9 float double A floating point number If an exact integer is passed as an argument then it is automatically converted to a float 35 10 number A floating point number Similar to double but when used as a result type then either an exact integer or a floating point number is returned depending on whether the result fits into an exact integer or not 35 11 symbol A symbol which will be passed to foreign code as a zero terminated string When declared as the result of foreign code the result should be a string and a symbol with the same name will be interned in the symbol table and returned to the caller 35 12 scheme pointer An untyped pointer to the contents of a non immediate Scheme object not allowed as return type The value f is also allowed and is passed as a NULL pointer Don t confuse this type with pointer which means something different a machine pointer object 35 13 nonnull scheme pointer As pointer but guaranteed not to be f Don t confuse this type with nonnull pointer which means something different a machine pointer object 35 14 c pointer An untyped operating system pointer or a locative The value f is also allowed and is passed as a NULL pointer If use
59. is ignored The default is suf fix keep shadowed macros Do not remove macro definitions with the same name as assigned toplevel variables the default is to remove the macro definition lambda lift Enable the optimization known as lambda lifting no lambda info Don t emit additional information for each Lambda expression currently the argument list after 4 Compiler command line format 7 CHICKEN User s Manual The User s Manual alpha conversion renaming no trace Disable generation of tracing information If a compiled executable should halt due to a runtime error then a list of the name and the line number if available of the last procedure calls is printed unless no trace is specified With this option the generated code is slightly faster no warnings Disable generation of compiler warnings nursery NUMBER stack size NUMBER Sets the size of the first heap generation of the generated executable to NUMBER bytes The parameter may be followed by a M m or K k suffix The default stack size depends on the target platform optimize leaf routines Enable leaf routine optimization optimize level LEVEL Enables certain sets of optimization options LEVEL should be an integer optimize level 0 does nothing optimize level 1 is equivalent to optimize leaf routines optimize level 2 is currently the same as optimize level 1 optimize level 3 is equivalent to optimize leaf routines unsafe output file FILENAME Speci
60. must be present This pattern is often used as and x pat to bind x to to the entire value that matches pat cf as patterns in ML or Haskell or pat 1 pat n matches if any of the subpatterns match At least one subpattern must be present All subpatterns must bind the same set of pattern variables not pat 1 pat n matches if none of the subpatterns match At least one subpattern must be present The subpatterns may not bind any pattern variables predicate pat 1 pat n Inthis pattern predicate must be an expression evaluating to a single argument function This pattern matches if predicate applied to the corresponding value is true and the subpatterns pat 1 pat n all match The predicate should not have side effects as the code generated by the pattern matcher may invoke predicates repeatedly in any order The predicate expression is bound in the same scope as the match expression i e free variables in predicate are not bound by pattern variables set identifier matches anything and binds identifier to a procedure of one argument that mutates the corresponding field of the matching value This pattern must be nested within a pair vector box or structure pattern For example the expression define x list 1 list 2 3 match x set setit setit 4 mutates the cadadr of X to 4 so that x is 1 2 4 get identifier matches anything and binds identifier to a procedure of zero a
61. object PTR Returns the Scheme object pointed to by the pointer PTR 32 1 11 pointer offset procedure pointer offset PTR N Returns a new pointer representing the pointer PTR increased by N 32 1 6 object gt pointer 159 CHICKEN User s Manual The User s Manual 32 1 12 pointer u8 ref procedure pointer u8 ref PTR Returns the unsigned byte at the address designated by PTR 32 1 13 pointer s8 ref procedure pointer s8 ref PTR Returns the signed byte at the address designated by PTR 32 1 14 pointer u16 ref procedure pointer ul6 ref PTR Returns the unsigned 16 bit integer at the address designated by PTR 32 1 15 pointer s16 ref procedure pointer s16 ref PTR Returns the signed 16 bit integer at the address designated by PTR 32 1 16 pointer u32 ref procedure pointer u32 ref PTR Returns the unsigned 32 bit integer at the address designated by PTR 32 1 17 pointer s32 ref procedure pointer s32 ref PTR Returns the signed 32 bit integer at the address designated by PTR 32 1 18 pointer f32 ref procedure pointer f32 ref PTR Returns the 32 bit float at the address designated by PTR 32 1 12 pointer u8 ref 160 CHICKEN User s Manual The User s Manual 32 1 19 pointer f64 ref procedure pointer f64 ref PTR Returns the 64 bit double at the address designated by PTR 32 1 20 pointer u8 set procedure pointer u8 set PTR N procedure set pointer u8 ref PTR N
62. port PORT defaults to the value of Current output port 18 2 4 port name procedure port name PORT Fetch filename from PORT This returns the filename that was used to open this file Returns a special tag string enclosed into parentheses for non file ports 18 2 5 port position procedure port position PORT Returns the current position of PORT as two values row and column number If the port does not support such an operation an error is signaled This procedure is currently only available for input ports 18 2 6 set port name procedure set port name PORT STRING Sets the name of PORT to STRING 18 2 1 current output port 63 CHICKEN User s Manual The User s Manual 18 3 Files 18 3 1 delete file procedure delete file STRING Deletes the file with the pathname STRING If the file does not exist an error is signaled 18 3 2 file exists procedure file exists STRING Returns STRING if a file with the given pathname exists or f otherwise 18 3 3 rename file procedure rename file OLD NEW Renames the file or directory with the pathname OLD to NEW If the operation does not succeed an error is signaled 18 4 String ports 18 4 1 get output string procedure get output string PORT Returns accumulated output of a port created with open output string 18 4 2 open input string procedure open input string STRING Returns a port for reading from STRING 18 4 3 open outpu
63. port from which data written by the sub process to stderr can be read 28 7 10 sleep procedure sleep SECONDS Puts the process to sleep for SECONDS Returns either 0 if the time has completely elapsed or the number of remaining seconds if a signal occurred 28 8 Hard and symbolic links 28 8 1 symbolic link procedure symbolic link FILENAME Returns true if FILENAME names a symbolic link 28 8 2 create symbolic link procedure create symbolic link OLDNAME NEWNAME Creates a symbolic link with the filename NEWNAME that points to the file named OLDNAME 28 7 8 process 126 CHICKEN User s Manual The User s Manual 28 8 3 read symbolic link procedure read symbolic link FILENAME Returns the filename to which the symbolic link FILENAME points 28 8 4 file link procedure file link OLDNAME NEWNAME Creates a hard link from OLDNAME to NEWNAME both strings 28 9 Permissions 28 9 1 file owner procedure file owner FILE Returns the user id of FILE FILE may be a filename or a file descriptor 28 9 2 file permissions procedure file permissions FILE Returns the permission bits for FILE You can test this value by performing bitwise operations on the result and the perm values FILE may be a filename or a file descriptor 28 9 3 file read access 28 9 4 file write access 28 9 5 file execute access procedure file read access FILENAME procedure file write access FILENAME
64. read 28 4 21 open write 28 4 22 open creat 28 4 23 open append 28 4 24 open excl 28 4 25 open noctty 28 4 26 open nonblock 28 4 27 open trunc 28 4 15 fileno stdout 121 CHICKEN User s Manual The User s Manual 28 4 28 open sync 28 4 29 open fsync 28 4 30 open binary 28 4 31 open text Flags for use with file open 28 4 32 open input file 28 4 33 open output file procedure open input file FILENO OPENMODE procedure open output file FILENO OPENMODE Opens file for the file descriptor FILENO for input or output and returns a port FILENO should be a positive exact integer OPENMODE specifies an additional mode for opening the file currently only the keyword append is supported which opens an output file for appending 28 4 34 port gt fileno procedure port gt fileno PORT If PORT is a file or tcp port then a file descriptor is returned for this port Otherwise an error is signaled 28 5 Retrieving file attributes 28 5 1 file access time 28 5 2 file change time 28 4 28 open sync 122 CHICKEN User s Manual The User s Manual 28 5 3 file modification time procedure file access time FILE procedure file change time FILE procedure file modification time FILE Returns time in seconds of the last access modification or change of FILE FILE may be a filename or a file descriptor If the file does not exist an error is signaled 28 5 4 file stat proc
65. scheme chicken lib LD LIBRARY PATH Linux 49 9 How can l increase the size of the trace shown when runtime errors are detected When a runtime error is detected Chicken will print the last entries from the trace of functions called unless your executable was compiled with the no trace option By default only 16 entries will be shown To increase this number pass the aN parameter to your executable 49 8 Why do built in units such as srfi 1 srfi 18 and posix fail to load 231 50 Optimizations 50 1 How can I obtain smaller executables If you don t need eval or the stuff in the extras library unit you can just use the Library unit declare uses library dileblay world n Don t forget to compile with the explicit use option Compiled with Visual C this generates an executable of around 240 kilobytes It is theoretically possible to compile something without the library but a program would have to implement quite a lot of support code on its own 50 2 How can I obtain faster executables There are a number of declaration specifiers that should be used to speed up compiled files declaring standard bindings is mandatory since this enables most optimizations Even if some standard procedures should be redefined you can list untouched bindings in the declaration Declaring extended bindings lets the compiler choose faster versions of certain internal library functions This might give another speedup Y
66. set setter PROC for a procedure that has no associated setter procedure yet is a very slow operation the old procedure is replaced by a modified copy which involves a garbage collection 18 19 2 continuation capture 78 CHICKEN User s Manual The User s Manual 18 20 2 getter with setter procedure getter with setter GETTER SETTER Returns a copy of the procedure GETTER with the associated setter procedure SETTER Contrary to the SRFI specification the setter of the returned procedure may be changed 18 21 Reader extensions 18 21 1 define reader ctor procedure define reader ctor SYMBOL PROC Define new read time constructor for read syntax For further information see the documentation for SRFI 10 18 21 2 set read syntax procedure set read syntax CHAR OR SYMBOL PROC When the reader is encounting the non whitespace character CHAR while reading an expression from a given port then the procedure PROC will be called with that port as its argument The procedure should return a value that will be returned to the reader A simple RGB color syntax set read syntax lambda port apply vector map cut string gt number lt gt 16 string chop read string 6 port 2 with input from string 1 2 SfOfOfO 3 read gt 1 2 240 240 240 3 If CHAR OR SYMBOL is a symbol then a so called read mark handler is defined In that case the handler procedure will be called when a charact
67. symbol 32 8 8 record instance procedure record instance X Returns t if X is an instance of a record type See also make record instance 32 8 9 record gt vector procedure record gt vector BLOCK Returns a new vector with the type and the elements of the record BLOCK 32 9 Procedure call and variable reference hooks 32 9 1 set invalid procedure call handler procedure set invalid procedure call handler PROC Sets an internal hook that is invoked when a call to an object other than a procedure is executed at runtime The procedure PROC will in that case be called with two arguments the object being called and a list of the passed arguments Access sequence elements as in ARC set invalid procedure call handler Lambda proc args cond string proc apply string ref proc args vector proc apply vector ref proc args else error call of non procedure proc hello D 4 gt Ho This facility does not work in code compiled with the unsafe setting 32 8 7 number of slots 171 CHICKEN User s Manual The User s Manual 32 9 2 unbound variable value procedure unbound variable value X Defines the value that is returned for unbound variables Normally an error is signalled use this procedure to override the check and return X instead To set the default behavior of signalling an error call unbound variable value with no arguments This facility does not
68. the dynamic linker MODE should be a list of symbols or a single symbol taken from the following set local If Local is given then any C C symbols defined in the dynamically loaded file are not available for subsequently loaded files and libraries Use this if you have linked foreign code into your dynamically loadable file and if you don t want to export them for example because you want to load another file that defines the same symbols global The default is g Lobal which means all C C symbols are available to code loaded at a later stage now If now is specified all symbols are resolved immediately lazy Unresolved symbols are resolved as code from the file is executed This is the default Note that this procedure does not control the way Scheme variables are handled this facility is mainly of interest when accessing foreign code 19 2 Read eval print loop 19 1 3 load noisily 82 CHICKEN User s Manual The User s Manual 19 2 1 repl procedure repl Start a new read eval print loop Sets the reset handler so that any invocation of reset restarts the read eval print loop Also changes the current exception handler to display a message write any arguments to the value of current error port and reset 19 3 Macros 19 3 1 get line number procedure get line number EXPR If EXPR is a pair with the car being a symbol and line number information is available for this expression then this procedure retur
69. unit has support for evaluation and macro handling This unit is used by default unless the program is compiled with the explicit use option 19 1 Loading code 19 1 1 load procedure load FILE EVALPROC Loads and evaluates expressions from the given source file which may be either a string or an input port Each expression read is passed to EVALPROC which defaults to eval On platforms that support it currently native Windows Linux ELF and Solaris Load can be used to load compiled programs cat x scm define hello print Hello CSC S X SCM csi q 1 gt load x so loading x so 2 gt hello Hello 3 gt The second argument to Load is ignored when loading compiled code If source code is loaded from a port then that port is closed after all expressions have been read Compiled code can be re loaded but care has to be taken if code from the replaced dynamically loaded module is still executing i e if an active continuation refers to compiled code in the old module Support for reloading compiled code dynamically is still experimental 19 1 2 load relative procedure load relative FILE EVALPROC Similar to Load but loads FILE relative to the path of the currently loaded file 19 1 3 load noisily procedure load noisily FILE key EVALUATOR TIME PRINTER As load but the result s of each evaluated toplevel expression is written to standard output If EVALUATOR is given a
70. with input pipe 28 2 2 call with output pipe procedure call with input pipe CMDLINE PROC MODE procedure call with output pipe CMDLINE PROC MODE Call PROC with a single argument a input or output port for a pipe connected to the subprocess named in CMDLINE If PROC returns normally the pipe is closed and any result values are returned 28 2 3 close input pipe 28 1 5 directory 116 CHICKEN User s Manual The User s Manual 28 2 4 close output pipe procedure close input pipe PORT procedure close output pipe PORT Closes the pipe given in PORT and waits until the connected subprocess finishes The exit status code of the invoked process is returned 28 2 5 create pipe procedure create pipe The fundamental pipe creation operator Calls the C function pipe and returns 2 values the file descriptors of the input and output ends of the pipe 28 2 6 open input pipe procedure open input pipe CMDLINE MODE Spawns a subprocess with the command line string CMDLINE and returns a port from which the output of the process can be read If MODE is specified it should be the keyword text the default or binary 28 2 7 open output pipe procedure open output pipe CMDLINE MODE Spawns a subprocess with the command line string CMDLINE and returns a port Anything written to that port is treated as the input for the process If MODE is specified it should be the keyword text the defaul
71. work in code compiled with the unsafe setting 32 10 Magic 32 10 1 object become procedure object become ALIST Changes the identity of the value of the car of each pair in ALIST to the value of the cdr Both values may not be immediate i e exact integers characters booleans or the empty list define x i used to be a string define y and now i am a vector object become list cons x y x gt and now i am a vector y gt and now i am a vector eq x y gt t Note this operation invokes a major garbage collection The effect of using object become on evicted data see object evict is undefined Previous Unit tcp Next Interface to external functions and variables 32 9 2 unbound variable value 172 33 Interface to external functions and variables e Accessing external objects e Foreign type specifiers e Embedding e Callbacks e Locations e Other support procedures e C interface Previous Supported language Next chicken setup 33 Interface to external functions and variables 173 34 Accessing external objects 34 1 foreign code syntax foreign code STRING Executes the embedded C C code STRING which should be a sequence of C statements which are executed and return an unspecified result foreign code doSomeInitStuff gt lt unspecified gt Code wrapped inside foreign code may not invoke callbacks into Scheme 34 2 foreign value synt
72. 193 38 2C Callback iii A a 193 38 3 C callback adjust stack Immits oie erred ES EEE EENE E 194 ERAT C m PRU A 195 39 1 detine Loca EE 195 SAGA RN 195 SA EN 195 39 4 Other support orocedures eeececeseceenceeeececseecesaeceeaeeceaceceeeecsaeseaaeceeaeeeeaeeceeeeseeseaaeceeaeeeeaeeeeaees 196 39 5 APEC HALO P E 196 TU ai 197 OLE SAVE ia iia da 197 20 2 restore Aaa Anibal Sabias 197 AORE BR KE 197 CHICKEN User s Manual The User s Manual Chicken User s Manual 40 C interface 40 4 C make charactere iir err t PER ORTU AR e E e d E hase o al Eve dos pavo iod eE e orae edo Cole na s 197 4 5 C SCHEME END OF LIST ertt d e dee IRE 197 40 6 C word C SCHEME END OF ELE 197 40 7 C word C SCHEME E E E 197 40 8 C word C SCHEME TRUE 198 A AO E 198 40 10 eet 198 AQ VAC E E 198 LOMA GNU ee Ee 198 40 13 E 198 AO l4 C e EE 198 40 15 Cint t e 198 OA A NN 198 TA ere rere ree 199 CACO Bek Sc ia 199 A E 199 AICA US E 199 40 21 E SIZEOR STRING EE 199 40 22 SIZEOE DN RETURN REENEN 199 40 23 C SIZEOF INTERNED SYMBOL ee eene nennen enne en enn 200 40 24 C SIZEOF PAIR 200 40 25 C SIZEOF ELONUM ceca Rr EY tee bere dd EE Pa ela cree Ee Ree RE ERES ERRARE 200 40 26 SIZBOE POINTER iiit estiviaintavbed a aiii 200 40 27 C SIZEOE EA ERR A EE 200 40 28 C SIZEOF TAGGED POINTER c oococcococononononnononononcnnonononononnononononononononononononocononinonininaninana
73. 28 11 19 signal alrm E 134 xii CHICKEN User s Manual The User s Manual Chicken User s Manual 28 Unit posix 26 147 rr DOLOR A gt EEA tadas A MIO EE 28 16 ERRNO Valles iii lana 26 10 1 errhO Derm i E 28 16 2 CTTDO ee 28 1 6 3 ETTDO STC 50556660 0i00csceesensseecdndsvavhiascsvevaisensnsudentesacduanobanadnacdsenrbocdsedasaedsacacacesacacss 28104 ele EE Re E DO A ss 28 16 60 ETTDO MMOERES NT Ee nas OSEANE ESEK EARNER EER ERRE EEEE E EE EREE NEEESE 28 16 7 CTEMOLD AE 25 106 5errno Child EE 25 16 9 errno nometmi iia aiii 28 16 10 TEE 28 16 LL HIRED LAIA EE Re Ee ee 28 16 14 ee E e Ee leet O O 28 10 16 Enola tia ada A NO 26 16 18 efrhno Spipe oo o tete ern xara e eae eege CHICKEN User s Manual The User s Manual Chicken User s Manual 28 Unit posix 25 16 19 CTO PIPE cue rem erento cans VOR HORTON YER UEBER ton and Pets Ele tena undedinteteataeastavacseds Re ae devin tdeds 140 25 16 20 errno ag alb ires eet PRO REDE EO REL RAS ERE anda ci I RED SERERE PREMO GE 140 28 10 21 erFHO TO S EE 140 28 10 22 ertno eXISL endete eto ege 140 28 16 23 errno wouldblock coccccccccccccccccnnncncnnnnocacanacanananananananan nono no nono nnn nano nonnnnononononononocanananonos 141 28 17 Finding EE 141 28 17 NN 141 28 18 Getting the hostname and system pformapop conan nennen ener 141 28 181 get hostename deaduesweeaees Pene dedu e sede an rada ede te Eee Ane ER eene ded 141 IES A ET 141
74. 4 return to host procedure return to host Exits the Scheme code and returns to the invoking context that called CHICKEN_ run or CHICKEN continue After return to host has been executed and once CHICKEN run returns you can invoke callbacks which have been defined with def ine external The eval library unit also provides boilerplate callbacks that simplify invoking Scheme code embedded in a C or C application a lot 37 5 CHICKEN eval C macro int CHICKEN eval C word exp C word result Evaluates the Scheme object passed in exp writing the result value to result The return value is 1 if the operation succeeded or 0 if an error occurred Call CHICKEN get error message to obtain a description of the error 37 6 CHICKEN eval string C macro int CHICKEN eval string char str C word result Evaluates the Scheme expression passed in the string Str writing the result value to result 37 7 CHICKEN eval to string C macro int CHICKEN eval to string C word exp char result int size Evaluates the Scheme expression passed in exp writing a textual representation of the result into result Size should specify the maximal size of the result string 37 8 CHICKEN eval string to string C macro int CHICKEN eval string to string char str char result int size Evaluates the Scheme expression passed in the string Str writing a textual representation of the result into result size should specify the maximal size
75. 6 4 gt utr fac 9 2 Writing Scheme scripts 19 CHICKEN User s Manual The User s Manual 5 gt fac 3 gt 6 tr SYMBOL Disables tracing of the given toplevel procedures br SYMBOL Sets a breakpoint at the procedures named SYMBOL Breakpoint can also be trigged using the breakpoint procedure ubr SYMBOL Removes breakpoints Ke Continues execution from the last invoked breakpoint breakall Enable breakpoints for all threads this is the default breakonly THREAD Enable breakpoints only for the thread returned by the expression THREAD info Lists traced procedures and breakpoints step EXPR Evaluates EXPR in single stepping mode On each procedure call you will be presented with a menu that allows stepping to the next call leaving single stepping mode or triggering a breakpoint Note that you will see some internal calls and unsafe or heavily optimized compiled code might not be stepped at all Single stepping mode is also possible by invoking the singlestep procedure You can define your own toplevel commands using the top Level command procedure 9 4 toplevel command procedure toplevel command SYMBOL PROC HELPSTRING Defines or redefines a toplevel interpreter command which can be invoked by entering SYMBOL PROC will be invoked when the command is entered and may read any required argument via read or read line If the optional argument HELPSTRING is given it will be listed by the
76. 70 328 0 number O Dytes incerto terre E E E E 170 FAR e Ee EC 171 E EE ET 171 32 8 9 TECOLG gt VECIOE EE 171 32 9 Procedure call and variable reference books 171 xvi CHICKEN User s Manual The User s Manual Chicken User s Manual 32 Unit lolevel 32 9 1 eermpvalhd orocedure call bhandler nan nc enne 171 32 9 2 onbound varable value conoce none non n AEEA nono no nono naconanananos 172 SEN LEE 172 32 AOD Object become ti AAA ee edit 172 33 Interface to external functions and Variables sccsssccccssssccsssscccssssccccsssscccssssccecessccecesscccsssceecess 173 34 ACCESSING external A A io 174 34 1 AGEL EN EE 174 A ncs erre E Ree OE ERU gus ANE ESEE EEE ORE E EERE EIE ANE 174 SE RENE 174 A RN 174 34 3 define Toreren vartable et irri rettet tette en nette PU Long ei tag eene e Precio deve ata 175 34 6 detin foreign reCOEd esres tr iere tr ERE RR EU EERE ER ARRIERE TERR EE TRIN NER EATEN RARE 175 34 6 1 TYPENAME SLOTNAME vu ENEE 176 34 6 2 DNVRBENAME SLOTNAME sel 176 GEERT deeg EE dE EE 176 34 0 4 de SEtF CLOE E 176 346S SIEUT TIU Tm 177 34 7 detine foreign enum eee ha extet e en aUe te eue estu Deae to aaa eed oeuvre uso on enl Nou eua aen ee et een 177 SE We le EE 178 34 0 Torero Ee EE 178 34 10 foreig safe lambda EE 178 34 11 foreign Safe lambd ar cintas 178 SE rer le E 179 E CEE SDOCHBEES aoi bie d aou aP imp a Mid M Ud Mu Ru MM 180 35 l A ter Cotto rt erre erre sae dia n
77. 99 gt 102 three is 3 13 9 Foreign Declare H4 lt Abbreviation for foreign declare 13 10 Sharp Prefixed Symbol SUR Reads like a normal symbol 13 7 Multiline String Constant 28 CHICKEN User s Manual The User s Manual 13 11 Bang SE Interpretation depends on the directly following characters Only the following are recognized Any other case results in a read error 13 11 1 Line Comment e If followed by whitespace or a slash then everything up the end of the current line is ignored 13 11 2 Eof Object e If followed by the character sequence eof then the self evaluating end of file object is returned 13 11 3 DSSSL Formal Parameter List Annotation e If followed by any of the character sequences optional rest or key then a symbol with the same name and prefixed with is returned 13 11 4 Read Mark Invocation e If a read mark with the same name as the token is registered then its procedure is called and the result of the read mark procedure will be returned 13 12 Case Sensitive Expression Zcs Read the next expression in case sensitive mode regardless of the current global setting 13 13 Case Insensitive Expression Aci Read the next expression in case insensitive mode regardless of the current global setting 13 11 Bang 29 CHICKEN User s Manual The User s Manual 13 14 Conditional Expansion FEATURE EXPR Equivalent to cond expand FEATURE EXPR el
78. ATHNAME Fetch extension from local file destdir PATHNAME Specify alternative installation prefix for packaging Ignore all following arguments Note that the options are processed exactly in the order in which they appear in the command line 41 7 Windows notes chicken setup works on Windows when compiled with Visual C but depends on the tar and gunzip tools to extract the contents of an egg The best way is to download an egg either manually or with chicken setup fetch and extract its contents with a separate program like winzip the CHICKEN REPOSITORY environment variable has to be set in addition to CHICKEN HOME to a directory where your compiled extensions should be located The setup scripts will not always work under Windows and the extensions may require libraries that are not provided for Windows or work differently Under these circumstances it is recommended to perform the required steps to build an extension manually The required UNIX tools are also available as Windows binaries Google or ask on the CHICKEN mailing list if you need help locating them 41 7 Windows notes 215 CHICKEN User s Manual The User s Manual 41 8 Security When extensions are downloaded and installed one is executing code from potentially compromised systems This applies also when chicken setup executes system tests for required extensions As the code has been retrieved over the network effectively untrusted code is going to
79. Additionally the code generated to match a structure pattern like Foo pat 1 the name Foo This name also should not be shadowed Previous Non standard macros and special forms Next Declarations 15 5 Code Generation pat n refers to 47 16 Declarations 16 1 declare syntax declare DECLSPEC Process declaration specifiers Declarations always override any command line settings Declarations are valid for the whole compilation unit source file the position of the declaration in the source file can be arbitrary Declarations are ignored in the interpreter but not in code evaluated at compile time by eval when or in syntax extensions loaded via require extension or require for syntax DECLSPEC may be any of the following 16 2 always bound declaration specifier always bound SYMBOL Declares that the given variables are always bound and accesses to those have not to be checked 16 3 block declaration specifier block Assume global variables are never redefined This is the same as specifying the block option 16 4 block global 16 5 hide declaration specifier block global SYMBOL declaration specifier hide SYMBOL Declares that the toplevel bindings for SYMBOL should not be accessible from code in other compilation units or by eval Access to toplevel bindings declared as block global is also more efficient 16 6 bound to procedure declaration specifier bound to proce
80. BARN T 34 VA SEET UE 34 14 3 5 re EE 35 14 3 6 letal ini adds 35 14 3 7 let values NN 35 14 3 8 letrec val es idad 35 UE WEE E 35 14 3 MOE KE 36 ER SR RE E 36 14 4 Substitution forms and mac 36 14 4 1 CefiME COMStANE 5 cscescnccsorcsacecacacacscocecesecsencsserssessvecesecessuesseesonsasavavassvasacdsueasacdsansoncevanacacscasacases 36 14 A EE 36 E Ce MIM ACEO EE 37 E A RA 37 145 d genaue Tee Ree EE 37 VAD WE RE 37 GT 37 DA SS WIEN EE 38 14 6 Record gelen 38 14 6 1 sce frie P COT iia idas 38 14 6 2 define record TE 38 14 6 3 defin record AAN 39 EA ele RE 39 TAR ASSET EE 39 14 7 2 COMAEX PAN DE 39 TATI NETTE didas 40 NAAA EE 40 147 5 me Te EE A0 EROS EE 41 INA EE 41 15 Pattern Mate dina ita iii 42 15 1 Pattern Matching Expressions cccssccessssssscsesscsenscesssesscesnsncenscesenescesnscsssceensesensccsencecenaseesnesenss 42 15 2 SE EE 44 CHICKEN User s Manual The User s Manual Chicken User s Manual 15 Pattern Matching 15 3 Match SET E 45 15 4 Record Str ct res Pattern cnin a Add d e 46 15 5 Code GEMELALI ONY EE 46 A a a ia 48 ege Ee 48 ee Ee 48 A 48 PAN ee DEE 48 16 5 HdE EE 48 16 6 bound t procedure ie ertt eue ete ee an e eee EEEE ANE aE Aaaa EE Fe Rai 48 EME DLE OLIO LLLI 40 ef e 49 16 9 erer EE E TE 49 16 VOsCOMS tam EE 49 e TE 49 16 12 emi
81. BITS Bit 5 is one for t and zero for f other values the empty list the value of unbound identifiers the undefined value void and end of file Bits 1 4 are equal to C SPECIAL BITS bits 5 to 8 contain an identifying number for this type of object The following constants are defined C SCHEME END OF LIST C SCHEME UNDEFINED C SCHEME UNBOUND C SCHEME END OF FILE Non immediate objects are blocks of data represented by a pointer into the heap The first word of the data block contains a header which gives information about the type of the object The header has the size of a machine word usually 32 bits 64 bits on 64 bit architectures bits 1 to 24 contain the length of the data object which is either the number of bytes in a string or byte vector or the the number of elements for a vector or for a structure type bits 25 to 28 contain the type code of the object bits 29 to 32 contain miscellaneous flags used for garbage collection or internal data type dispatching These flags are C GC FORWARDING BIT Flag used for forwarding garbage collected object pointers C BYTEBLOCK BIT Flag that specifies whether this data object contains raw bytes a string or byte vector or pointers to other data objects C SPECIALBLOCK BIT Flag that specifies whether this object contains a special non object pointer value in its first slot An example for this kind of objects are closures which are a vector type object with the code pointer as the
82. CHICKEN User s Manual The User s Manual CHICKEN User s Manual The User s Manual Chicken User s Manual L ItrodUut llo cece ada i Ee ERE REPRE IHRER E ESU ERE AU EXE REPE RERUR 1 2 Basic mode OF OPE aiii ii RI 3 3 Intcorll Edu io 4 4 Compiler command Ime ue E is reser pr PVP pH HERE EEDUHERREEEERREREREERMEXE Ani Aa ESNA ENSA aS naiinis 5 RECIPI V T mem 10 A T T Tn 12 6 1 A simple example with one source Dei 12 ANITA ON 12 APARATO 12 6 1 3 Running your program 12 6 2 An example with multiple files 1 3 REENEN eaa eure Tue cvv bee agere cb dE ENEE 13 6 2 Writing your source Tiles terree eter setenta tex oi Hoe sued EENE e ERR VE ee acero 13 6 2 2 Compiling and running your program ener enne rennen senten nter nns 13 T Extendino A ia 15 s Dstrtibuting E el aa 16 EA Usine a a a aa at 17 9 1 Interpreter command line format 17 9 2 ss o eer tr eae etes nene e ona etae aa e Ub LIN ee ER Tuo e Ee ERE VE AY He aS 18 9 3 Toplevel WEE 19 9 4 toplevel commafid ter eite eee t ie lae ER casted MEE CER E dE 20 NS O O eelere 20 A e LEE 20 9 7 Auto completion and editii eecceecceesececsseceseeceeseeceececeeeeecsaeeesaecseaaeceaceceeneeeeeeeaaeceeaeeneaeeeeeeeees 21 9 8 Accessing documentation ect reiten ete tete Y eee etae ea re eee cada nd cdt Rau 21 I Supported laity eo sooo ce eae eR ee ee 22 Ti Deviations from the VIDERI DO EDEN 23 Ea 24 EN A 2J 13 1 Multiline
83. Currently native threads are not supported The runtime system is not reentrant and the garbage collection algorithm would be made much more complicated since the location of every object whether it is allocated on the stack or on the heap or completely outside the GC able data space has to be checked this would be rather complex and inefficient in a situation where multiple threads are involved 45 9 How can I specialize a generic function method to matchinstances of every class 224 46 Platform specific 46 1 How do generate a DLL under MS Windows tm Use CSC in combination with the dll option C gt csc foo scm dll 46 2 How do generate a GUI application under Windows tm Invoke CSC with the windows option Or pass the DC_ WINDOWS GUI option to the C compiler and link with the GUI version of the runtime system that s Libchicken gui static lib The GUI runtime displays error messages in a message box and does some rudimentary command line parsing 46 3 Compilin very targe files under Windows with the Microsoft C compiler fails with a message indicating insufficient heap space It seems that the Microsoft C compiler can only handle files up to a certain size and it doesn t utilize virtual memory as well as the GNU C compiler for example Try closing running applications If that fails try to break up the Scheme code into several library units 46 4 When I run csi inside an emacs buffer under Windows no
84. E BODY is the same as letrec NAME lambda VARIABLE BODY NAME 14 3 3 cut syntax cut SLOT syntax cute SLOT Syntactic sugar for specializing parameters 14 3 4 define values syntax define values NAME EXP Defines several variables at once with the result values of expression EXP 14 2 4 let optionals 34 CHICKEN User s Manual The User s Manual 14 3 5 fluid let syntax fluid let VAR1 X1 BODY Binds the variables VAR1 dynamically to the values X1 during execution of BODY 14 3 6 let values syntax let values NAME EXP BODY Binds multiple variables to the result values of EXP All variables are bound simultaneously 14 3 7 let values syntax let values NAME EXP BODY Binds multiple variables to the result values of EXP The variables are bound sequentially let values a b values 2 3 p a b p e 5 14 3 8 letrec values syntax letrec values NAME EXP BODY Binds the result values of EXP to multiple variables at once All variables are mutually recursive letrec values odd even values lambda n if zero n f even subl n Lambda n if zero n t odd subl n odd 17 gt t 14 3 9 parameterize syntax parameterize PARAMETER1 X1 BODY Binds the parameters PARAMETER1 dynamically to th
85. ERE START procedure substring index ci WHICH WHERE START 20 9 7 string split 98 CHICKEN User s Manual The User s Manual Searches for first index in string WHERE where string WHICH occurs If the optional argument START is given then the search starts at that index substring index Ci is a case insensitive version of substring index 20 10 Combinators 20 10 1 any procedure any X Ignores it s argument and always returns t This is actually useful sometimes 20 10 2 constantly procedure constantly X Returns a procedure that always returns the values X regardless of the number and value of its arguments constantly X lambda args X 20 10 3 complement procedure complement PROC Returns a procedure that returns the boolean inverse of PROC complement PROC lt gt lambda x not PROC x 20 10 4 compose procedure compose PROC1 PROC2 Returns a procedure that represents the composition of the argument procedures PROC1 PROC2 compose F G lambda args call with values Lambda apply G args F compose is equivalent to values 20 9 11 substring index 99 CHICKEN User s Manual The User s Manual 20 10 5 conjoin procedure conjoin PRED Returns a procedure that returns t if its argument satisfies the predicates PRED lt enscript highlight scheme gt conjoin odd positive 33 t conjoin odd positive 33 f lt enscri
86. EXP STRING ARG Signals an error if EXP evaluates to false An optional message STRING and arguments ARG may be supplied to give a more informative error message If compiled in unsafe mode either by specifying the unsafe compiler option or by declaring unsafe then this expression expands to an unspecified value The result is the value of EXP 14 7 2 cond expand syntax cond expand FEATURE CLAUSE Expands by selecting feature clauses This form is allowed to appear in non toplevel expressions Predefined feature identifiers are situation specific compile eval Library match compiling srfi 11 srfi 15 srfi 31 srfi 26 srfi 16 utils regex srfi 4 match srfi 1 srfi 69 srfi 28 extras srfi 8 srfi 6 srfi 2 srfi 0 srfi 10 srfi 9 srfi 55 srfi 61 chicken srfi 23 srfi 30 srfi 39 srfi 62 srfi 17 srfi 12 load srfi 69 srfi 28 extras srfi 8 srfi 6 srfi 2 srfi 0 srfi 10 srfi 9 srfi 55 srfi 61 chicken srfi 23 srfi 30 srfi 39 srfi 62 srfi 17 srfi 12 library is implicit eval match csi srfi 11 srfi 15 srfi 31 srfi 26 srfi 16 srfi 69 srfi 28 extras srfi 8 srfi 6 srfi 2 srfi 0 srfi 10 srfi 9 srfi 55 srfi 61 chicken srfi 23 srfi 30 srfi 39 srfi 62 srfi 17 srfi 12 library is implicit The following feature identifiers are available in all situations machine byte order machine type software type software version where the actual feature identifier is pl
87. HICKEN User s Manual The User s Manual 20 1 11 shuffle procedure shuffle LIST Returns LIST with its elements sorted in a random order 20 1 12 tail procedure tail X LIST Returns true if X is one of the tails cdr s of LIST 20 2 String port extensions 20 2 1 call with input string procedure call with input string STRING PROC Calls the procedure PROC with a single argument that is a string input port with the contents of STRING 20 2 2 call with output string procedure call with output string PROC Calls the procedure PROC with a single argument that is a string output port Returns the accumulated output string 20 2 3 with input from string procedure with input from string STRING THUNK Call procedure THUNK with the current input port temporarily bound to an input string port with the contents of STRING 20 2 4 with output to string procedure with output to string THUNK Call procedure THUNK with the current output port temporarily bound to a string output port and return the accumulated output string 20 1 11 shuffle 89 CHICKEN User s Manual The User s Manual 20 3 Formatted output 20 3 1 printf procedure fprintf PORT FORMATSTRING ARG procedure printf FORMATSTRING ARG procedure sprintf FORMATSTRING ARG procedure format FORMATSTRING ARG Simple formatted output to a given port fprintf the value of current output port printf or a string S
88. HICKEN User s Manual The User s Manual Binding constructs for optional procedure arguments ARGS should be a rest parameter taken from a lambda list Let optionals binds VAR1 to available arguments in parallel or to DEFAULT1 if not enough arguments were provided Let optionals binds VAR1 sequentially so every variable sees the previous ones If a single variable RESTVAR is given then it is bound to any remaining arguments otherwise it is an error if any excess arguments are provided let optionals one two a 1 b 2 c a list a b c gt one two one 14 3 Other binding forms 14 3 1 and let syntax and let BINDING EXP1 EXP2 SRFI 2 Bind sequentially and execute body BINDING can be a list of a variable and an expression a list with a single expression or a single variable If the value of an expression bound to a variable is f the and Letz form evaluates to f and the subsequent bindings and the body are not executed Otherwise the next binding is performed If all bindings expressions evaluate to a true result the body is executed normally and the result of the last expression is the result of the and Letz form See also the documentation for SRFI 2 14 3 2 rec syntax rec NAME EXPRESSION syntax rec NAME VARIABLE BODY Allows simple definition of recursive definitions rec NAME EXPRESSION is equivalent to Letrec NAME EXPRESSION NAME and rec NAME VARIABL
89. LOT definition should be a list of one of the following forms TYPE SLOTNAME or TYPE SLOTNAME SIZE 34 4 define foreign type 175 CHICKEN User s Manual The User s Manual The latter form defines an array of SIZE elements of the type TYPE embedded in the structure For every slot the following accessor procedures will be generated 34 6 1 TYPENAME SLOTNAME TYPENAME SLOTNAME FOREIGN RECORD POINTER INDEX A procedure of one argument a pointer to a C structure that returns the slot value of the slot SLOTNAME If a SIZE has been given in the slot definition then an additional argument INDEX is required that specifies the index of an array element 34 6 2 TYPENAME SLOTNAME set TYPENAME SLOTNAME set FOREIGN RECORD POINTER INXDEX VALUE A procedure of two arguments a pointer to a C structure and a value that sets the slot value of the slot SLOTNAME in the structure If a SIZE has been given in the slot definition then an additional argument INDEX is required for the array index If a slot type is of the form const then no setter procedure will be generated Slots of the types struct or union are accessed as pointers to the embedded struct or union and no setter will be generated Additionally special record declarations DECL may be given where each declaration consists of a list of the form KEYWORD ARGUMENT 1 The available declarations are 34 6 3 constructor constructor NA
90. ME Generate a constructor procedure with no arguments that has the name NAME a symbol that returns a pointer to a structure of this type The storage will be allocated with malloc 3 34 6 4 destructor destructor NAME Generate a destructor function with the name NAME that takes a pointer to a structure of this type as its single argument and releases the storage with f ree 3 If the argument is f the destructor procedure does nothing 34 6 define foreign record 176 CHICKEN User s Manual The User s Manual 34 6 5 rename rename EXPRESSION Evaluates EXPRESSION at compile macro expansion time and applies the result which should be a procedure to the string representation of the name of each accessor procedure generated Another or the same string should be returned which in turn is taken as the actual name of the accessor An example require for syntax srfi 13 define foreign record Some Struct rename compose string downcase cut string translate lt gt constructor make some struct destructor free some struct int xCoord int yCoord will generate the following procedures make some struct C POINTER free some struct C POINTER some struct xcoord C POINTER gt NUMBER some struct ycoord C POINTER gt NUMBER some struct xcoord set C POINTER NUMBER some struct ycoord set C POINTER NUMBER 34 7 define foreign enum syntax define foreign
91. N system and assumes a working knowledge of Scheme The manual is split in the following sections Basic mode of operation Compiling Scheme files Using the compiler Explains how to use CHICKEN to compile programs and execute them Using the interpreter Invocation and usage of CSi the CHICKEN interpreter Supported language The language implemented by CHICKEN deviations from the standard and extensions Interface to external functions and variables Accessing C and C code and data chicken setup Packaging and installing extension libraries Data representation How Scheme data is internally represented Bugs and limitations Yes there are some Introduction CHICKEN User s Manual The User s Manual FAQ A list of Frequently Asked Questions about CHICKEN and their answers Acknowledgements A list of some of the people that have contributed to make CHICKEN what it is Bibliography Links to documents that may be of interest 1 Introduction 2 Basic mode of operation The compiler translates Scheme source code into fairly portable C that can be compiled and linked with most available C compilers CHICKEN supports the generation of executables and libraries linked either statically or dynamically Compiled Scheme code can be loaded dynamically or can be embedded in applications written in other languages Separate compilation of modules is fully supported The most portable way of creating separately linkabl
92. NAME SNAME instance ref CNAME SNAME Previous Accessing external objects Next Embedding 36 Mappings int unsigned char unsigned short unsigned int unsigned int unsigned long float double double void void unsigned char unsigned char char unsigned short short uint32 t int32 t float double char char void TYPE enum NAME struct NAME TYPE amp T1 lt T2 gt union NAME CALLCONV RTYPE ATYPE CNAME CNAME amp 185 37 Embedding Compiled Scheme files can be linked with C code provided the Scheme code was compiled in embedded mode by passing DC EMBEDDED to the C compiler this will disable generation of a main function CSC will do this when given the embedded option Alternatively pass embedded to csc The following C API is available 37 1 CHICKEN parse command line C function void CHICKEN parse command line int argc char argv int heap Parse the programs command line contained in argc and argv and return the heap stack and symbol table limits given by runtime options of the form or choose default limits The library procedure argv can access the command line only if this function has been called by the containing application 37 2 CHICKEN initialize C function int CHICKEN initialize int heap int stack int symbols void to Initializes the Scheme execution context and memory heap holds the number of byt
93. R Copies the object X recursively into the memory pointed to by the foreign pointer object returned by ALLOCATOR which should be a procedure of a single argument the number of bytes to allocate The freshly copied object is returned This facility allows moving arbitrary objects into static memory but care should be taken when mutating evicted data setting slots in evicted vector like objects to non evicted data is not allowed It is possible to set characters bytes in evicted strings or byte vectors though It is advisable not to evict ports because they might be mutated by certain file operations object evict is able to handle circular and shared structures but evicted symbols are no longer unique a fresh copy of the symbol is created so define x foo define y object evict foo y gt foo eq x y gt f define z object evict bar bar eq car z cadr z gt Jt The ALLOCATOR defaults to allocate 32 5 2 object evict to location procedure object evict to location X PTR LIMIT As object evict but moves the object at the address pointed to by the machine pointer PTR If the number of copied bytes exceeds the optional LIMIT then an error is signalled specifically a composite condition of types exn and evi ct The latter provides a Limit property which holds the exceeded limit Two values are returned the evicted object and a new pointer pointing to the first free address after the evicted object
94. SO and loaded dynamically into a running application Previous index html Next Using the compiler 2 Basic mode of operation 3 3 Introduction The interface to chicken is intentionally simple System dependent makefiles shell scripts or batch files should perform any necessary steps before and after invocation of chicken A program named CSC provides a much simpler interface to the Scheme and C compilers and linker Enter csc help on the command line for more information 3 Introduction 4 Compiler command line format chicken FILENAME OPTION FILENAME is the complete pathname of the source file that is to be translated into C A filename argument of specifies that the source text should be read from standard input Note that the filename has to be the first argument to Chicken Possible options are analyze only Stop compilation after first analysis pass benchmark mode Equivalent to no trace no lambda info optimize level 3 fixnum arithmetic disable interrupts block lambda lift block Enable block compilation When this option is specified the compiler assumes that global variables are not modified outside this compilation unit Specifically toplevel bindings are not seen by eval and unused toplevel bindings are removed case insensitive Enables the reader to read symbols case insensitive The default is to read case sensitive in violation of R5RS This option registers the case insensitive feature id
95. SS Creates a new foreign pointer object initialized to point to the address given in the integer ADDRESS 32 1 2 allocate procedure allocate BYTES Returns a pointer to a freshly allocated region of static memory This procedure could be defined as follows 1 define allocate foreign lambda c pointer malloc integer 32 1 3 free procedure free POINTER Frees the memory pointed to by POINTER This procedure could be defined as follows define free foreign lambda c pointer free integer 32 1 4 null pointer procedure null pointer Another way to say address gt pointer 0 32 1 5 null pointer procedure null pointer PTR Returns t if PTR contains a NULL pointer or f otherwise 32 Unit lolevel 158 CHICKEN User s Manual The User s Manual 32 1 6 object gt pointer procedure object gt pointer X Returns a pointer pointing to the Scheme object X which should be a non immediate object Note that data in the garbage collected heap moves during garbage collection 32 1 7 pointer procedure pointer X Returns t if X is a foreign pointer object and f otherwise 32 1 8 pointer procedure pointer PTR1 PTR2 Returns t if the pointer like objects PTR1 and PTR2 point to the same address 32 1 9 pointer gt address procedure pointer gt address PTR Returns the address to which the pointer PTR points 32 1 10 pointer gt object procedure pointer gt
96. STRING or f if that variable is not defined 18 8 7 machine byte order procedure machine byte order Returns the symbol Little endian orbig endian depending on the machine s byte order 18 8 3 build platform 69 CHICKEN User s Manual The User s Manual 18 8 8 machine type procedure machine type Returns a symbol specifying the processor on which this process is currently running which is one of the following alpha mips hppa ultrasparc sparc ppc ia64 x86 x86 64 unknown 18 8 9 on exit procedure on exit THUNK Schedules the zero argument procexdures THUNK to be executed before the process exits either explicitly via exit or implicitly after exection of the last toplevel form Note that finalizers for unreferenced finalized data are run before exit procedures 18 8 10 software type procedure software type Returns a symbol specifying the operating system on which this process is currently running which is one of the following windows unix macos ecos unknown 18 8 11 software version procedure software version Returns a symbol specifying the operating system version on which this process is currently running which is one of the following linux freebsd netbsd 18 8 8 machine type 70 CHICKEN User s Manual The User s Manual openbsd macosx hpux solaris sunos unknown 18 8 12 c runtime procedure c runtime Returns a symbol that designates what kind of C r
97. TYPE INIT can be an arbitrary expression that is used to initialize the variable NAME is accessible from Scheme just like any other foreign variable defined by define foreign variable define external foo int 42 foreign lambda int C return foo gt 42 Note don t be tempted to assign strings or bytevectors to external variables Garbage collection moves those objects around so it is very bad idea to assign pointers to heap data If you have to do so then copy the data object into statically allocated memory for example by using obj ect evict Results of type scheme object returned by define external are always allocated in the secondary heap that is not in the stack 38 2 C callback C function C word C callback C word closure int argc This function can be used to invoke the Scheme procedure closure argc should contain the number of arguments that are passed to the procedure on the temporary stack Values are put onto the temporary stack 38 Callbacks 193 CHICKEN User s Manual The User s Manual with the C_save macro 38 3 C_callback_adjust_stack_limits C function void C callback adjust stack limits C word ptr The runtime system uses the stack as a special allocation area and internally holds pointers to estimated limits to distinguish between Scheme data objects inside the stack from objects outside of it If you invoke callbacks at wildly differing stack levels these limits may shift from invo
98. ULL 35 21 nonnull c string Similar to nonnull c string but if used as a result type the pointer returned by the foreign code will be freed using the C libraries f ree after copying This type specifier is not valid as a result type for callbacks defined with define external 35 22 void Specifies an undefined return value Not allowed as argument type 35 16 scheme or c pointer 182 CHICKEN User s Manual The User s Manual 35 23 const TYPE The foreign type TYPE with an additional const specifier 35 24 enum NAME An enumeration type Handled internally as an integer 35 25 pointer TYPE c pointer TYPE An operating system pointer or a locative to an object of TYPE 35 26 nonnull pointer TYPE nonnull c pointer TYPE As pointer TYPE but guaranteed not to be f NULL 35 27 ref TYPE A C reference type Reference types are handled the same way as pointers inside Scheme code 35 28 struct NAME A struct of the name NAME which should be a string Structs can not be directly passed as arguments to foreign function neither can they be result values Pointers to structs are allowed though 35 29 template TYPE ARGTYPE A C template type For example vector lt int gt would be specified as template vector int Template types can not be directly passed as arguments or returned as results 35 30 union NAME A union of the name NAME which should be a string Unions can not be di
99. Y procedure fpmax X Y procedure fp X Y procedure fp X Y procedure fp X Y procedure fp X Y procedure fp X Y Arithmetic floating point operations In safe mode these procedures throw a type error with non float arguments except f Lonum which returns f In unsafe mode these procedures do not check their arguments A non flonum argument in unsafe mode can crash the system 18 1 42 signum procedure signum N Returns 1 if N is positive 1 if N is negative or 0 if N is zero signum is exactness preserving 18 1 43 finite procedure finite N Returns f if N is negative or positive infinity and f otherwise 18 2 File Input Output 18 2 1 current output port procedure current output port PORT 18 1 39 fp 62 CHICKEN User s Manual The User s Manual Returns default output port If PORT is given then that port is selected as the new current output port Note that the default output port is not buffered Use set buf fering mode if you need a different behaviour 18 2 2 current error port procedure current error port PORT Returns default error output port If PORT is given then that port is selected as the new current error output port Note that the default error output port is not buffered Use set buffering mode if you need a different behaviour 18 2 3 flush output procedure flush output PORT Write buffered output to the given output
100. ZEOF TAGGED POINTER C macro int C SIZEOF TAGGED POINTER These are macros that return the size in words needed for a data object of a given type 40 29 C character code C macro int C character code C word character 40 30 C unfix C macro int C unfix C word fixnum 40 31 C flonum magnitude C macro double C flonum magnitude C word flonum 40 23 C SIZEOF INTERNED SYMBOL 200 CHICKEN User s Manual The User s Manual 40 32 C c string C function char C c string C word string 40 33 C num to int C function int C num to int C word fixnum or flonum 40 34 C pointer address C function void C pointer address C word pointer These macros and functions can be used to convert Scheme data objects back to C data Note that C c string returns a pointer to the character buffer of the actual Scheme object and is not zero terminated 40 35 C header size C macro int C header size C word x 40 36 C header bits C macro int C header bits C word x Return the number of elements and the type bits of the non immediate Scheme data object X 40 37 C block item C macro C word C block item C word x int index This macro can be used to access slots of the non immediate Scheme data object X index specifies the index of the slot to be fetched starting at 0 Pairs have 2 slots one for the car and one for the cdr Vectors have one slot for each element 40 38 C u i car C macro C word C u i ca
101. ager string append or getenv HOME 52 Interpreter 235 53 Extensions 53 1 How can install Chicken eggs to a non default location You can just set the CHICKEN REPOSITORY environment variable It should contain the path where you want eggs to be installed export CHICKEN REPOSITORY chicken chicken setup extensionname In order to make programs including csi see these eggs you should set this variable when you run them Alternatively you can call the repository path Scheme procedure before loading the eggs as in repository path home azul chicken use format modular Note however that using repository path as above hard codes the location of your eggs in your source files While this might not be an issue in your case it might be safe to keep this configuration outside of the source code that is specifying it as an environment variable to make it easier to maintain 53 2 Can install chicken eggs as a non root user Yes just install them in a directory you can write Previous Bugs and limitations Next Acknowledgements 53 Extensions 236 54 Acknowledgements Many thanks to Nico Amtsberg William Annis Marc Baily Peter Barabas Jonah Beckford Arto Bendiken Peter Bex Jean FranA ois Bignolles Dave Bodenstab Fabian BAgqhlke T Kurt Bond Ashley Bone Dominique Boucher Terence Brannon Roy Bryant Adam Buchbinder Hans Bulfone Category 5 Taylor Campbell Franklin Chen Thomas Chu
102. aker1 CheneyMTA html Revised 5 Report on the Algorithmic Language Scheme http www schemers org Documents Standards R5RS Previous Acknowledgements 55 Bibliography 239
103. an executable program in the executable path usually usr local bin 41 4 1 install extension 207 CHICKEN User s Manual The User s Manual 41 4 3 install script procedure install script ID FILELIST INFOLIST Similar to install program but additionally changes the file permissions of all files in FILELIST to executable for installing shell scripts 41 4 4 run syntax run FORM Runs the shell command FORM which is wrapped in an implicit quasiquote run csc is treated specially and passes V if verbose has been given to chicken setup and feature compiling extension options to the compiler 41 4 5 compile syntax compile FORM Equivalent to run csc FORM 41 4 6 make syntax make TARGET DEPENDENT COMMAND ARGUMENTS A make macro that executes the expressions COMMAND when any of the dependents DEPENDENT have changed to build TARGET This is the same as the make extension which is available separately For more information see make 41 4 7 patch procedure patch WHICH REGEX SUBST Replaces all occurrences of the regular expression REGEX with the string SUBST in the file given in WHICH If WHICH is a string the file will be patched and overwritten If WHICH is a list of the form OLD NEW then a different file named NEW will be generated 41 4 8 copy file procedure copy file FROM TO Copies the file or directory recursively given in t
104. andard output and exit 9 2 Writing Scheme scripts Since UNIX shells use the notation for starting scripts anything following the characters is ignored with the exception of the special symbols optional key rest and eof The easiest way is to use the SCript option like this cat foo usr local bin csi script print eval with input from string car command line arguments read chmod x foo foo 3 4 N o o The parameter command Line arguments is set to a list of the parameters that were passed to the Scheme script Scripts can be compiled to standalone executables don t forget to declare used library units CHICKEN supports writing shell scripts in Scheme for these platforms as well using a slightly different approach The first example would look like this on Windows C gt type foo bat csibatch 0 1 2 953 4 5 6 7 8 9 print eval with input from string car command line arguments read C gt foo 3 4 7 Like UNIX scripts batch files can be compiled Windows batch scripts do not accept more than 8 arguments Since it is sometimes useful to run a script into the interpreter without actually running it for example to test specific parts of it the option SS can be used as an alternative to script ss PATHNAME is equivalent to script PATHNAME but invokes main command line arguments after loading all top level forms of the script file The result
105. at bar c include lt stdio h gt include chicken h extern int callout int int int extern int callin C word x int callout int x int y int z C word ptr C alloc C SIZEOF LIST 3 C word lst printf This is callout d d d n x y Z lst C List amp ptr 3 C fix x C fix y C fix z return callin lst Note callin will have GC d the data in ptr 40 44 C_gc_protect 203 CHICKEN User s Manual The User s Manual csc Top sch bar c o foo foo This is callout 1 2 3 This is callin 1 2 3 123 Notes Scheme procedures can call C functions and C functions can call Scheme procedures but for every pending C stack frame the available size of the first heap generation the nursery will be decreased because the C stack is identical to the nursery On systems with a small nursery this might result in thrashing since the C code between the invocation of C from Scheme and the actual calling back to Scheme might build up several stack frames or allocates large amounts of stack data To prevent this it is advisable to increase the default nursery size either when compiling the file using the nursery option or when running the executable using the S runtime option Calls to Scheme C may be nested arbitrarily and Scheme continuations can be invoked as usual but keep in mind that C stack frames will not be recovered when a Scheme procedure call from C does not return
106. atform dependent 14 6 2 define record printer 39 CHICKEN User s Manual The User s Manual In addition the following feature identifiers may exist app Lyhook extras lot ptables dload Libf fi For further information see the documentation for SRFI 0 14 7 3 ensure syntax ensure PREDICATE EXP ARGUMENTS Evaluates the expression EXP and applies the one argument procedure PREDICATE to the result If the predicate returns f an error is signaled otherwise the result of EXP is returned If compiled in unsafe mode either by specifying the unsafe compiler option or by declaring unsafe then this expression expands to an unspecified value If specified the optional ARGUMENTS are used as arguments to the invocation of the error signalling code as in error ARGUMENTS If no ARGUMENTS are given a generic error message is displayed with the offending value and PREDICATE expression 14 7 4 eval when syntax eval when SITUATION EXP Controls evaluation compilation of subforms SITUATION should be one of the symbols eval compile or Load When encountered in the evaluator and the situation specifier eval is not given then this form is not evaluated and an unspecified value is returned When encountered while compiling code and the situation specifier compile is given then this form is evaluated at compile time When encountered while compiling code and the situation specifier Load is not given then this f
107. ax foreign value STRING TYPE Evaluates the embedded C C expression STRING returning a value of type given in the foreign type specifier TYPE print foreign value my version string c string 34 3 foreign declare syntax foreign declare STRING Include given strings verbatim into header of generated file 34 4 define foreign type syntax define foreign type NAME TYPE ARGCONVERT RETCONVERT Defines an alias for TYPE with the name NAME a symbol TYPE may be a type specifier or a string naming a C type The namespace of foreign type specifiers is separate from the normal Scheme namespace The optional arguments ARGCONVERT and RETCONVERT should evaluate to procedures that map argument and result values to a value that can be transformed to TYPE define foreign type char vector nonnull c string compose list gt string vector gt list compose list gt vector string gt list define strlen foreign lambda int strlen char vector strlen a b c gt 3 34 Accessing external objects 174 CHICKEN User s Manual The User s Manual define memset foreign lambda char vector memset char vector char int memset 4 X 3 gt X X X Foreign type definitions are only visible in the compilation unit in which they are defined so use include to use the same definitions in multiple files 34 5 define foreign variable syntax define foreign variable NAME TYPE
108. ay be a condition a string or any other object If the optional argument STRING is given it is printed before the error message STRING defaults to Error 18 10 6 procedure information procedure procedure information PROC Returns an s expression with debug information for the procedure PROC or f if PROC has no associated debug information 18 10 7 reset procedure reset Reset program Invokes reset handler 18 10 8 warning procedure warning STRING EXP Displays a warning message if warnings are enabled with enable warnings and continues execution 18 10 9 singlestep procedure singlestep THUNK Executes the code in the zero procedure THUNK in single stepping mode 18 11 Garbage collection 18 11 1 gc procedure gc FLAG Invokes a garbage collection and returns the number of free bytes in the heap The flag specifies whether a 18 10 5 print error message 73 CHICKEN User s Manual The User s Manual minor f or major t GC is to be triggered If no argument is given t is assumed When the argument is Ft all pending finalizers are executed 18 11 2 memory statistics procedure memory statistics Performs a major garbage collection and returns a three element vector containing the total heap size in bytes the number of bytes currently used and the size of the nursery the first heap generation Note that the actual heap is actually twice the size given in the heap size
109. be evaluated When chicken setup 1s run as root the whole system is at the mercy of the build instructions note that this is also the case every time you install software via sudo make install so this is not specific to the CHICKEN extension mechanism Security conscious users should never run Chicken setup as root A simple remedy is to set the environment variable CHICKEN REPOSITORY which will transparently place the repository at an arbitrary user selected location Alternatively obtain write execute access to the default location of the repository usually usr local lib chicken to avoid running as root 41 9 Other modes if installation It is possible to install extensions directly from a Subversion repository or from a local checkout by using the svn or local options By using either the SVN client program which must be installed or file system Operations all necessary files will be copied into the current directory creating a subdirectory named EXTENSIONNAME egg dir built and subsequently installed Dependency information which is necessary to ensure required extensions are also installed is downloaded automatically If you have no internet connection or don t want to connect you can als use a local file containing the necessary dependency information The fetch tree option retrieves the canonical repository file at http www call with current continuation org eggs repository writing it to stdout Redirecting this out
110. because CHICKEN uses a copying semi space collector 18 11 3 set finalizer procedure set finalizer X PROC Registers a procedure of one argument PROC that will be called as soon as the non immediate data object X is about to be garbage collected with that object as its argument Note that the finalizer will not be called when interrupts are disabled This procedure returns X 18 11 4 set gc report procedure set gc report FLAG Print statistics after every GC depending on FLAG A value of t shows statistics after every major GC A true value different from t shows statistics after every minor GC f switches statistics off 18 12 Other control structures 18 12 1 andmap procedure andmap PROC LIST1 Repeatedly calls PROC with arguments taken from LIST1 If any invocation should return f the result of andmap is f If all invocations return a true result then the result of andmap is t 18 12 2 ormap procedure ormap PROC LIST1 Repeatedly calls PROC with arguments taken from LIST1 If any invocation should return a value different from f then this value is returned as the result of ormap If all invocations return f then the result of ormap is f 18 11 1 gc 74 CHICKEN User s Manual The User s Manual 18 12 3 promise procedure promise X Returns t if X is a promise returned by de Lay or f otherwise 18 13 String utilities 18 13 1 reverse list gt string pro
111. by default in the interpreter CSi csc hello scm 02 dl A simple makefile is needed as well Makefile for UNIX systems hello hello o runtime o library o eval o extras o CC o hello hello o runtime o library o eval o extras o lm hello o chicken h runtime o chicken h library o chicken h eval o chicken h extras o chicken h Now we have all files together and can create an tarball containing all the files 9 6 tar cf hello tar Makefile hello c runtime c library c eval c extras c chicken gzip hello tar This is of naturally rather simplistic Things like enabling dynamic loading estimating the optimal stack size and selecting supported features of the host system would need more configuration and build time support All this can be addressed using more elaborate build scripts makefiles or by using http galinha ucpel tche br autoconf automake Note also that the size of the application can still be reduced by removing extras and eval and compiling hello scm with the explicit use option For more information study the CHICKEN source code and or get in contact with the author Previous index html Next Using the interpreter 8 Distributing compiled C files 16 9 Using the interpreter CHICKEN provides an interpreter named CSi for evaluating Scheme programs and expressions interactively 9 1 Interpreter command line format csi FILENAME OPTION where FILENAME specifies a file with Scheme sou
112. called with three arguments the symbol and key and the new value For information about the contents of the program database contact the author Loaded code via the extend option has access to the library units extras srfi 1 srfi 4 utils regex and the pattern matching macros Multithreading is not available Note that the macroexpansion canonicalization phase of the compiler adds certain forms to the source program These extra expressions are not seen by User preprocessor pass but by user pass 7 Extending the compiler 15 8 Distributing compiled C files It is relatively easy to create distributions of Scheme projects that have been compiled to C The runtime system of CHICKEN consists of only two handcoded C files runtime c and chicken h plus the file chicken config h which is generated by the build process All other modules of the runtime system and the extension libraries are just compiled Scheme code The following example shows a minimal application which should run without changes on the most frequent operating systems like Windows Linux or FreeBSD Let s take a simple Hello world hello scm print Hello world Compiled to C we get hello c We need the files chicken hand runtime c which contain the basic runtime system plus the three basic library files Library c eval cand extras c which contain the same functionality as the library linked into a plain CHICKEN compiled application or which is available
113. cation to invocation Callbacks defined with define external will perform appropriate adjustments automatically but if you invoke C callback manually you should perform a C callback adjust stack limits to make sure the internal limits are set properly pt r should point to some data object on the stack The call will make sure the limits are adjusted so that the value pointed to by ptr is located in the stack Previous Embedding Next Locations 38 2 C callback 194 39 Locations It is also possible to define variables containing unboxed C data so called locations It should be noted that locations may only contain simple data that is everything that fits into a machine word and double precision floating point values 39 1 define location syntax define location NAME TYPE INIT Identical to define external NAME TYPE INIT but the variable is not accessible from outside of the current compilation unit it is declared static 39 2 let location syntax let location NAME TYPE INIT BODY Defines a lexically bound location 39 3 location syntax location NAME syntax location X This form returns a pointer object that contains the address of the variable NAME If the argument to location is not a location defined by define Location define external or let location then Location X is essentially equivalent to make locative X See the manual chapter or Locatives for more information about l
114. cedure reverse list gt string LIST Returns a string with the characters in LIST in reverse order This is equivalent to List gt string reverse LIST but much more efficient 18 14 Generating uninterned symbols 18 14 1 gensym procedure gensym STRING OR SYMBOL Returns a newly created uninterned symbol If an argument is provided the new symbol is prefixed with that argument 18 14 2 string gt uninterned symbol procedure string gt uninterned symbol STRING Returns a newly created unique symbol with the name STRING 18 15 Standard Input Output 18 15 1 port procedure port X Returns t if X is a port object or f otherwise 18 12 3 promise 75 CHICKEN User s Manual The User s Manual 18 15 2 print procedure print EXP1 EXP2 Outputs the arguments EXP1 EXP2 using display and writes a newline character to the port that is the value of Current output port Returns its first argument 18 15 3 print procedure print EXP1 Similar to print but does not output a terminating newline character and performs a f Lush outout after writing its arguments 18 16 User defined named characters 18 16 1 char name procedure char name SYMBOL OR CHAR CHAR This procedure can be used to inquire about character names or to define new ones With a single argument the behavior is as follows If SYMBOL OR CHAR is a symbol then Char name returns the character with this nam
115. cess has not terminated yet e t if the process exited normally or f otherwise either the exit status if the process terminated normally or the signal number that terminated stopped the process 28 7 8 process procedure process COMMANDLINE ARGUMENTLIST ENVIRONMENT Passes the string COMMANDLINE to the host system s shell that is invoked as a subprocess and returns three values an input port from which data written by the sub process can be read an output port from which any 28 7 3 process execute 125 CHICKEN User s Manual The User s Manual data written to will be received as input in the sub process and the process id of the started sub process Blocking reads and writes to or from the ports returned by process only block the current thread not other threads executing concurrently If ARGUMENTLIST is given then the invocation of the subprocess is not done via the shell but directly The arguments are directly passed to process execute as is ENVIRONMENT Not using the shell may be preferrable for security reasons On native Windows the ARGUMENTLIST and ENVIRONMENT arguments are ignored 28 7 9 process procedure process COMMANDLINE ARGUMENTLIST ENVIRONMENT Like process but returns 4 values an input port from which data written by the sub process can be read an output port from which any data written to will be received as input in the sub process the process id of the started sub process and an input
116. command 9 5 History access The interpreter toplevel accepts the special object INDEX which returns the result of entry number INDEX in the history list If the expression for that entry resulted in multiple values the first result or an unspecified value for no values is returned If no INDEX is given and if a whitespace or closing paranthesis character follows the then the result of the last expression is returned Note that the value returned is implicitly quoted 9 6 set describer procedure set describer TAG PROC Sets a custom description handler that invokes PROC when the d command is invoked with a record type object that has the type TAG a symbol PROC is called with two arguments the object to be described and an output port It should write a possibly useful textual description of the object to the passed output port For 9 3 Toplevel commands 20 CHICKEN User s Manual The User s Manual example 1 gt define record point x y 2 gt set describer point lambda pt o print a point with x point x pt 3 gt d make point 1 2 a point with x 1 and y 2 9 7 Auto completion and edition On platforms that support it it is possible to get auto completion of symbols history over different csi sessions and a more feature full editor for the expressions you type using the http galinha ucpel tche br readline egg by Tony Garnock Jones It is very useful for interactive use of csi To enabl
117. content of the gc root is initialized to an unspecified value 37 17 CHICKEN delete gc root C function void CHICKEN delete gc root void root Deletes the gc root 37 18 CHICKEN gc root ref C macro C word CHICKEN gc root ref void root Returns the value stored in the gc root 37 19 CHICKEN gc root set C macro void CHICKEN gc root set void root C word value Sets the content of the GC root to a new value Sometimes it is handy to access global variables from C code 37 20 CHICKEN global lookup C function void CHICKEN global lookup char name Returns a GC root that holds the global variable with the name name If no such variable exists NULL is returned 37 21 CHICKEN global ref C function C word CHICKEN global ref void global Returns the value of the global variable referenced by the GC root global 37 16 CHICKEN new gc root 191 CHICKEN User s Manual The User s Manual 37 22 CHICKEN global set C function void CHICKEN global set void global C word value Sets the value of the global variable referenced by the GC root global to value Previous Foreign type specifiers Next Callbacks 37 22 CHICKEN global set 192 38 Callbacks To enable an external C function to call back to Scheme the form foreign safe Lambda or foreign safe lambda has to be used This generates special code to save and restore important state information during execution of C code There are two ways of callin
118. dure make queue Returns a newly created queue 20 5 3 queue procedure queue X Returns t if X is a queue or f otherwise 20 3 1 printf 91 CHICKEN User s Manual The User s Manual 20 5 4 queue gt list procedure queue gt list QUEUE Returns QUEUE converted into a list where the first element of the list is the same as the first element of the queue The resulting list may share memory with the queue object and should not be modified 20 5 5 queue add procedure queue add QUEUE X Adds X to the rear of QUEUE 20 5 6 queue empty procedure queue empty QUEUE Returns t if QUEUE is empty or f otherwise 20 5 7 queue first procedure queue first QUEUE Returns the first element of QUEUE If QUEUE is empty an error is signaled 20 5 8 queue last procedure queue last QUEUE Returns the last element of QUEUE If QUEUE is empty an error is signaled 20 5 9 queue remove procedure queue remove QUEUE Removes and returns the first element of QUEUE If QUEUE is empty an error is signaled 20 5 10 queue push back procedure queue push back QUEUE ITEM Pushes an item into the first position of a queue i e the next queue remove will return ITEM 20 5 4 queue gt list 92 CHICKEN User s Manual The User s Manual 20 5 11 queue push back list procedure queue push back list QUEUE LIST Pushes the items in item list back onto the queue so that car LIST becomes the n
119. dure SYMBOL Declares that the given identifiers are always bound to procedure values 16 Declarations 48 CHICKEN User s Manual The User s Manual 16 7 c options declaration specifier c options STRING Declares additional C C compiler options that are to be passed to the subsequent compilation pass that translates C to machine code This declaration will only work if the source file is compiled with the CSC compiler driver 16 8 check c syntax declaration specifier check c syntax declaration specifier not check c syntax Enables or disables syntax checking of embedded C C code fragments Checking C syntax is the default 16 9 compress literals declaration specifier compress literals THRESHOLD INITIALIZER The same as the compress literals compiler option The threshold argument defaults to 50 If the optional argument INITIALTZER is given then the literals will not be created at module startup but when the procedure with this name will be called 16 10 constant declaration specifier constant SYMBOL Declares the procedures with the names SYMBOL as constant that is as not having any side effects This can help the compiler to remove non side effecting expressions 16 11 export declaration specifier export SYMBOL The opposite of hide All given identifiers will be exported and all toplevel variables not listed will be hidden and not be accessible outside of this co
120. e or f if no character is defined under this name If SYMBOL OR CHAR is a character then the name of the character is returned as a symbol or f if the character has no associated name If the optional argument CHAR is provided then SYMBOL OR CHAR should be a symbol that will be the new name of the given character If multiple names designate the same character then the write will use the character name that was defined last char name space gt space char name space gt space char name bell gt f char name integer gt char 7 gt f char name bell integer gt char 7 char name bell gt Abell char gt integer char name bell gt 7 18 17 Vectors 18 15 2 print 76 CHICKEN User s Manual The User s Manual 18 17 1 vector copy procedure vector copy VECTOR1 VECTOR2 COUNT Copies contents of VECTOR1 into VECTOR2 If the argument COUNT is given it specifies the maximal number of elements to be copied If not given the minimum of the lengths of the argument vectors is copied Exceptions exn bounds 18 17 2 vector resize procedure vector resize VECTOR N INIT Creates and returns a new vector with the contents of VECTOR and length N If N is greater than the original length of VECTOR then all additional items are initialized to INIT If INIT is not specified the contents are initialized to some unspecified value 18 18 The unspecified value 18 18 1 void pr
121. e 124 CHICKEN User s Manual The User s Manual On native Windows process execute ignores the ENVIRONMENT LIST arguments 28 7 4 process fork procedure process fork THUNK Creates a new child process with the UNIX system call fork Returns either the PID of the child process or 0 If THUNK is given then the child process calls it as a procedure with no arguments and terminates 28 7 5 process run procedure process run PATHNAME LIST Creates a new child process using the UNIX system call fork that executes the program given by the string PATHNAME using the UNIX system call execv The PID of the new process is returned If LIST is not specified then PATHNAME is passed to a program named by the environment variable SHELL or bin sh if the variable is not defined so usual argument expansion can take place 28 7 6 process signal procedure process signal PID SIGNAL Sends SIGNAL to the process with the id PID using the UNIX system call kill SIGNAL defaults to the value of the variable signal term 28 7 7 process wait procedure process wait PID NOHANG Suspends the current process until the child process with the id PID has terminated using the UNIX system call waitpid If PID is not given then this procedure waits for any child process If NOHANG is given and not f then the current process is not suspended This procedure returns three values e PID or 0 if NOHANG is true and the child pro
122. e SYMBOL with its slots initialized to ARG1 To illustrate define record point x y expands into something quite similar to begin define make point x y make record instance point x y define point x and record instance x eq point block ref x 0 define point x p block ref p 1 define point x set p x block set p 1 x define point y p block ref p 2 define point y set p y block set p 1 y 32 8 5 move memory procedure move memory FROM TO BYTES Copies BYTES bytes of memory from FROM to TO FROM and TO may be strings primitive byte vectors SRFI 4 byte vectors see ref Unit srfi 4 memory mapped files foreign pointers as obtained from a call to foreign lambda for example or locatives if BYTES is not given and the size of the source or destination operand is known then the maximal number of bytes will be copied Moving memory to the storage returned by locatives will cause havoc if the locative refers to containers of non immediate data like vectors or pairs 32 8 6 number of bytes procedure number of bytes BLOCK Returns the number of bytes that the object BLOCK contains BLOCK may be any non immediate value 32 8 3 object copy 170 CHICKEN User s Manual The User s Manual 32 8 7 number of slots procedure number of slots BLOCK Returns the number of slots that the object BLOCK contains BLOCK may be a vector record structure pair or
123. e aede 74 RR SE EE RE 74 15 11 4 s t ge report iia 74 18 12 Other control structures ne nene tenete nnne nnn 74 E e E RA 74 IN PABULI R S 74 185 12 3 Re 75 IS He OI uL RO 75 18 13 L A AAN 75 18 14 Generating uninterned svmbols tenens nnen netten ennt snnt nisse tenens 75 EE E SUAE EE 75 18 142 string uninterned symbol sese eene ennene NANS NNE neee nns 75 EARL A 75 IAN ERN DuC H UR M 75 IE TEE 76 EE 76 18 16 User defined named characterg na nena na tenen nennen 76 Be E EE nidad dar He 18 I7 e ee He I Lee lr tdi TT AAA IA rrr rede Ee EE TT 18 18 The unspecitied E TT E E EE TT 18 19 LE EI e TT LES De ele ee OTE TT Eeler ET TT 18 19 3 continuation pce Eee erit ease va Tae dvo ed eroe dd se Lene e USE ee 78 18 19 4 contimuatior graft RAROS 78 18 19 5 contim ation ret rn eoe on a e o n o ee a eh ER VR nd Xn Flea ERE AEn aa mida a Ta thea Rea Hear 78 18 20 SeLtets xs on cp t had cases o isle bati ie se arie Ee Ee 78 J820 1 EE 78 EE EE E 79 18 21 Gi Ee EE 79 18 21 1 lege eet Oria i e err E her ER MERO daria criar dais 79 Ee E EE 79 18 21 setesharporead yMtax oc issssssatsvnnsccedvsnsacesvadessnaasidecenedeasestdyteeuenedeunnd eaantnssgevvenseenvavostieest ctedssasades 80 18 21 4 set parameterized read syntax lo eecceeccecscesseceesseeeaceceeeeeeseeeeaaeceeaece
124. e entities is supported by so called units A unit is a single compiled object module that contains a number of toplevel expressions that are executed either when the unit is the main unit or if the unit is used To use a unit the unit has to be declareed as used like this declare uses UNITNAME The toplevel expressions of used units are executed in the order in which the units appear in the uses declaration Units may be used multiple times and uses declarations may be circular the unit is initialized at most once To compile a file as a unit add a unit declaration declare unit UNITNAME When compiling different object modules make sure to have one main unit This unit is called initially and initializes all used units before executing its toplevel expressions The main unit has no unit declaration Another method of using definitions in separate source files is to include them This simply inserts the code in a given file into the current file include FILENAME Macro definitions are only available when processed by include Macro definitions in separate units are not available since they are defined at compile time i e the time when that other unit was compiled macros can optionally be available at runtime see def ine macro in Substitution forms and macros On platforms that support dynamic loading of compiled code like Windows and most ELF based systems like Linux or BSD code can be compiled into a shared object
125. e entry point into the compiled Scheme code You should add the following declarations at the head of your code lakhs el chick include cen h extern void C toplevel C word C word C word C noret 47 2 How can add compiled user passes To add a compiled user pass instead of an interpreted one create a library unit and recompile the main unit of the compiler in the file chicken scm with an additional uses declaration Then link all compiler modules and your compiled extension to create a new version of the compiler like this assuming all sources are in the current directory cat userpass scm userpass scm My very own compiler pass declare unit userpass Perhaps more user passes extensions are added let old user pass user pass Lambda x let x2 do something with x if old old x2 x2 2 csc C X userpass scm csc chicken scm c o chicken extended o uses userpass gcc chicken extended o support o easyffi o compiler o optimizer o batch drive C backend o userpass o csc ldflags libs o chicken extended a o oe On platforms that support it Linux ELF Solaris Windows VC compiled code can be loaded via extend just like source files see Load in the User s Manual 47 Customization 227 48 Macros 48 1 Why doesn t my fancy macro work in compiled code Macro bodies that are defined and used in a compiled source file are evaluated during compilation and so have
126. e environment variable CHICKEN HOME is set then its value will be returned As a last option if the environment variable CHICKEN PREFIX is set then chicken home will return CHICKEN PREFIX share 19 6 Eval 19 6 1 eval procedure eval EXP ENVIRONMENT Evaluates EXP and returns the result of the evaluation The second argument is optional and defaults to the value of interaction environment Previous Unit library Next Unit extras 19 5 1 chicken home 86 20 Unit extras This unit contains a collection of useful utility definitions This unit is used by default unless the program is compiled with the explicit use option 20 1 Lists 20 1 1 alist ref procedure alist ref KEY ALIST TEST DEFAULT Looks up KEY in ALIST using TEST as the comparison function or eqv if no test was given and returns the cdr of the found pair or DEFAULT which defaults to f 20 1 2 alist update procedure alist update KEY VALUE ALIST TEST If the list ALIST contains a pair of the form KEY X then this procedure replaces X with VALUE and returns ALIST If ALIST contains no such item then alist update returns KEY VALUE ALIST The optional argument TEST specifies the comparison procedure to search a matching pair in ALIST and defaults to eqv 20 1 3 atom procedure atom X Returns t if X is not a pair This is identical to not pair from Unit srfi 1 but kept for historical reasons 20 1 4 rassoc
127. e form SOURCE DEST if you want to copy into a particular sub directory the destination directory will be created as needed If DEST is a relative pathname lt it will be copied into the extension repository The optional argument INFOLIST should be an association list that maps symbols to values this list will be stored as ID setup at the same location as the extension code Currently the following properties are used 41 4 1 1 syntax extension property syntax Marks the extension as syntax only No code is compiled the extension is intended as a file containing macros to be loaded at compile macro expansion time 41 4 1 2 require at runtime extension property require at runtime ID Specifies extensions that should be loaded via requi re at runtime This is mostly useful for syntax extensions that need additional support code at runtime 41 4 1 3 version extension property version STRING Specifies version string 41 4 1 4 documentation extension property documentation FILENAME The filename of a HTML document containing extension specific documentation This file should be given in the file list passed to install extension and a link to it will be automatically included in the index 41 4 Procedures and macros available in setup scripts 206 CHICKEN User s Manual The User s Manual page accessible via chicken setup docindex 41 4 1 5 examples extension property examples FILENAME
128. e it install the egg and put this in your cSirc file use readline regex current input port make gnu readline port gnu history install file manager string append or getenv HOME cs More details are available in the egg s documentation 9 8 Accessing documentation You can access the manual directly from CSi using the http galinha ucpel tche br man extension by http galinha ucpel tche br Mario Domenech Goulart To enable it install the egg and put this in your CSi rc file use man man Load Then in CSi you can search for definitions using man search as in man search case Note that the search uses regular expressions To view the documentation for one entry from the manual use man help as in man help case lambda Previous Using the compiler Next Supported language 9 6 set describer 21 10 Supported language e Deviations from the standard e Extensions to the standard e Non standard read syntax e Non standard macros and special forms e Pattern matching e Declarations e Parameters e Unit library basic Scheme definitions e Unit eval evaluation and macro handling e Unit extras useful utility definitions e Unit srfi 1 List Library e Unit srfi 4 Homogeneous numeric vectors e Unit srfi 13 String library e Unit srfi 14 character set library e Unit match pattern matching runtime support e Unit regex regular expressions e Unit srfi 18 multithreading e Unit
129. e ota eor lel ie euentu pee a e cies qe ines CUNT E UE TERRE NUR 180 A 180 35 9 byte UNS1 PMED D O 180 EE 180 32 5 SHOT unsigned ShOft E 180 35 6 int unsigned int int32 UNSIGNEC INt32 0 ee cece eeeeceeeesecceceeeesaeeeeaaeceeaeceeeeeseaeeeaeeseaaeceaeeceeeeees 180 35 7 integer unsigned integer integer32 unsigned integer32 integerO4 coooccnnnccnnnccnnonncnonnnnnnncnnnncnnnnnnn 180 35 8 long nsigned long eee nati nino irae tree tte REENEN Eege eec Peer cere 180 35 9 float double AA Eee eoe iv SEENEN 181 SD MO MUMBER EE 181 DOLD SYMON E 181 E Ee Er eu 181 2325 13 nonnull scheme pOlltet cou cocotte eee orto de ek ee er EE edd edd geseet 181 EA A C 181 35 15 nonfull c poltnt r O 181 EAN e E 182 35 17 nonmn ll Dy te VECION EE 182 35 18 nonnull u8vector nonnull ul6vector nonnull u32vector nonnull s8vector nonnull s16vector nonnull s32vector nonnull 32 vector nonnull f64vector 182 KOR m T natin deen ous 182 33 20 NONMUIEC SUING ss22s E M 182 35 21 Toperten NO 182 ESO EE 182 33 23 const LY PE EEN 183 33 24 El NAMB E 183 CHICKEN User s Manual The User s Manual Chicken User s Manual 35 Foreign type specifiers 35 25 pointer TYPE c pointer TYPE enne entente enne 183 35
130. e values X1 during execution of BODY see also make parameter in ref Parameters Note that PARAMETER may be any expression that evaluates to a parameter procedure 14 3 5 fluid let 35 CHICKEN User s Manual The User s Manual 14 3 10 receive syntax receive NAME1 NAMEn VALUEEXP BODY syntax receive VALUEEXP SRFI 8 Syntactic sugar for call with values Binds variables to the result values of VALUEEXP and evaluates BODY The syntax receive VALUEEXP is equivalent to receive _ VALUEEXP _ 14 3 11 set values syntax set values NAME EXP Assigns the result values of expression EXP to multiple variables 14 4 Substitution forms and macros 14 4 1 define constant syntax define constant NAME CONST Define a variable with a constant value evaluated at compile time Any reference to such a constant should appear textually after its definition This construct is equivalent to de fine when evaluated or interpreted Constant definitions should only appear at toplevel Note that constants are local to the current compilation unit and are not available outside of the source file in which they are defined Names of constants still exist in the Scheme namespace and can be lexically shadowed If the value is mutable then the compiler is careful to preserve its identity CONST may be any constant expression and may also refer to constants defined via define constant previously This for shou
131. eaeecaeeseaeeeeaaecesaeeeeeeeeses 80 EPA OS 80 A E 81 EAU OA 81 KS MOA ME 81 Kee EE KEE 81 19 13 load NOISY iiss sssezwasSsevestsciienssapvecssvsadescnoasiastiduesy vecennadedes Edge deed eege g 81 CAPA O 82 19 1 5 set dynamic load mode aeaniee Ri enne tenente nente 82 19 2 R ad val print loOp O vas Fla 82 Eeer ER vi CHICKEN User s Manual The User s Manual Chicken User s Manual 19 Unit eval MOSS Eier E 83 IEN E E ne 83 TRAZA O ideas 83 1973 3 macroexpand E 83 19 3 4 macroexpand el nre NN 83 19 35 define ma cro EE 83 IEN ET 84 19 4 Loading extension MT E 84 19 4 l TEPOSILOPY EL deaduesvee dees Pedo dedo couse ae en are dee aee e Eee ne svi denen euo 84 194 2 extensiOD 1 Y LO 01 E O iiec iccirco rte ei vei or onsets vans cavndaaseonsaanedasvacadanavacd dX UR ERE TY Nba eov 84 LAA NN 84 EE ER 84 LPRA RN 85 ERAS A O 85 19 5 System 1nfOrriatiOR ii ENEE dE ENEE 85 TO LECCE EE 85 196 EE 86 PANA RE 86 SEENEN 87 QO D E EE 87 PUN MEET I RR ORT T TI 87 20 1 2 alistupdate EE 87 QO AS 1 103 RE 87 WOA EE 87 20 1 5 DU di daa Li eredi ese EEE Ee a ue EIN E E NE 87 20 1 6 e 88 20 T PCOMMPE CS Seo eegene 88 PUN REEL IURE 88 20 1 0 1ntetSperse oscar E n snes TEE E AREE RE ERO E EA AE ERE OR Fred Rare 88 PUBL E M 88 GAR RE EE 89 NA A IAN 89 RETTEN E 89 AEN WE ET EE 89 20 2 2 call with outpu t string eret ts A A tia 89 20 2 3 E Hee EE 89 20 2 4 With OUtpU EE
132. ed signal mask or signal unmask 28 12 Environment access 28 11 23 signal urg 135 CHICKEN User s Manual The User s Manual 28 12 1 current environment procedure current environment Returns a association list of the environment variables and their current values 28 12 2 setenv procedure setenv VARIABLE VALUE Sets the environment variable named VARIABLE to VALUE Both arguments should be strings If the variable is not defined in the environment a new definition is created 28 12 3 unsetenv procedure unsetenv VARIABLE Removes the definition of the environment variable VARIABLE from the environment of the current process If the variable is not defined nothing happens 28 13 Memory mapped UO 28 13 1 memory mapped file pocedure memory mapped file X Returns t if X is an object representing a memory mapped file or f otherwise 28 13 2 map file to memory procedure map file to memory ADDRESS LEN PROTECTION FLAG FILENO OFFSET Maps a section of a file to memory using the C function mmap ADDRESS should be a foreign pointer object or f LEN specifies the size of the section to be mapped PROTECTION should be one or more of the flags prot read prot write prot exec or prot none bitwise iored together FLAG should be one or more of the flags map fixed map shared map private map anonymous or map file FILENO should be the file descriptor of the mapped file The optional argument OFFSET
133. edure file stat FILE LINK Returns a 13 element vector with the following contents inode number mode as with file permissions number of hard links uid of owner as with file owner gid of owner size as with file size and access change and modification time as with file access time file change time and file modification time device id device type for special file inode blocksize and blocks allocated On Windows systems the last 4 values are undefined If the optional argument LINK is given and not f then the file statistics vector will be resolved for symbolic links otherwise symbolic links are not resolved 28 5 5 file position procedure file position FILE Returns the current file position of FILE which should be a port or a file descriptor 28 5 6 file size procedure file size FILENAME Returns the size of the file designated by FILE FILE may be a filename or a file descriptor If the file does not exist an error is signaled 28 5 7 regular file procedure regular file FILENAME Returns true if FILENAME names a regular file not a directory or symbolic link 28 6 Changing file attributes 28 5 3 file modification time 123 CHICKEN User s Manual The User s Manual 28 6 1 file truncate procedure file truncate FILE OFFSET Truncates the file FILE to the length OFFSET which should be an integer If the file size is smaller or equal to OFFSET then nothing is done FILE should be a
134. edure PROCEDURE or f if it is not an extended procedure 32 3 4 set procedure data procedure set procedure data PROCEDURE X Changes the data object contained in the extended procedure PROCEDURE to X define foo 32 2 2 tagged pointer 163 CHICKEN User s Manual The User s Manual letrec f lambda procedure data x x f set x extend procedure f 123 x foo gt 123 set procedure data foo hello foo gt hello 32 4 Bytevectors 32 4 1 byte vector procedure byte vector FIXNUM Returns a freshly allocated byte vector with FIXNUM as its initial contents 32 4 2 byte vector procedure byte vector X Returns t if X is a byte vector object or f otherwise 32 4 3 byte vector fill procedure byte vector fill BYTE VECTOR N Sets each element of BYTE VECTOR to N which should be an exact integer 32 4 4 byte vector gt list procedure byte vector gt list BYTE VECTOR Returns a list with elements taken from BYTE VECTOR 32 4 5 byte vector gt string procedure byte vector gt string BYTE VECTOR Returns a string with the contents of BYTE VECTOR 32 3 4 set procedure data 164 CHICKEN User s Manual The User s Manual 32 4 6 byte vector length procedure byte vector length BYTE VECTOR Returns the number of elements in BYTE VECTOR 32 4 7 byte vector ref procedure byte vector ref BYTE VECTOR INDEX Returns the byte at the INDEX
135. el 1 is equivalent to no trace debug level 2 does nothing the default disable interrupts Equivalent to the disable interrupts declaration No interrupt checks are generated for compiled programs disable stack overflow checks Disables detection of stack overflows This is equivalent to running the compiled executable with the 0 runtime option disable warning CLASS Disables specific class of warnings may be given multiple times The following classes are defined usage warnings related to command line arguments type warnings related to type conversion ext warnings related to extension libraries var warnings related to variable and syntax definitions and const warnings related to constant definitions syntax syntax related warnings redef warnings about redefinitions of standard or extended bi call warnings related to known procedure calls ffi warnings related to the foreign function interface dynamic This option should be used when compiling files intended to be loaded dynamically into a running Scheme program epilogue FILENAME Includes the file named FILENAME at the end of the compiled source file The include path is not searched This option may be given multiple times emit exports FILENAME Write exported toplevel variables to FILENAME emit external prototypes first Emit prototypes for callbacks defined with de fine external before any other foreign declarations This is sometimes useful when C C code e
136. entifier check imports Search for references to undefined global variables For each library unit accessed via declare uses the compiler will search a file named UNITNAME exports in the current include path and load its contents into the import table if found Also export information for extensions accessed through require extension will be searched and stored in the import table If a required extension does not provide explicit export information a exports file is searched as with used units After the analysis phase of the compiler referenced toplevel variables for which no assignment was found will generate a warning Also re assignments of imported variables will trigger a warning check syntax Aborts compilation process after macro expansion and syntax checks compress literals THRESHOLD Compiles quoted literals that exceed the size THRESHOLD as strings and parse the strings at run time This reduces the size of the code and speeds up compile times of the host C compiler but has a small run time performance penalty The size of a literal is computed by counting recursively the objects in the literal so a vector counts as 1 plus the count of the elements a pair counts as the counts of the car and the cdr respectively All other objects count 1 debug MODES Enables one or more compiler debugging modes MODES is a string of characters that select debugging information about the compiler that will be printed to sta
137. equired chicken version procedure required chicken version VERSION Signals an error if the version of CHICKEN that this script runs under is lexicographically less than VERSION the argument will be converted to a string first 41 4 22 required extension version procedure required extension version EXTENSION1 VERSIONI Checks whether the extensions EXTENSION1 are installed and at least of version VERSION1 The test is made by lexicographically comparing the string representations of the given version with the version of the installed extension If one of the listed extensions is not installed has no associated version information or is of a version older than the one specified 41 4 23 cross chicken procedure cross chicken Retrusn t if this system is configured for cross compilation or f otherwise 41 5 Examples for extensions The simplest case is a single file that does not export any syntax For example hello scm define hello name print Hello name I We need a Setup script to build and install our nifty extension hello setup compile the code into a dynamically loadable shared object will generate hello so or hello dll on Windows compile s hello scm Install as extension library install extension hello hello so Note install extension will recognized the SO extension and automatically do the right thing on Windows After entering chicken
138. er fileno procedure tcp listener port LISTENER Returns the file descriptor associated with LISTENER 30 8 tcp connect procedure tcp connect HOSTNAME TCPPORT Establishes a client side TCP connection to the machine with the name HOSTNAME a string at TCPPORT an exact integer and returns two values an input and output port for communicating with the remote process Note any I O on the ports returned will not block other running threads 30 9 tcp addresses procedure tcp addresses PORT Returns two values for the input or output port PORT which should be a port returned by either tcp accept or tcp connect the IP address of the local and the remote machine that are connected over the socket associated with PORT The returned addresses are strings in XXX XXX XXX XXX notation 30 10 tcp port numbers procedure tcp port numbers PORT Returns two values for the input or output port PORT which should be a port returned by either tcp accept or tcp connect the TCP port numbers of the local and the remote machine that are connected over the socket associated with PORT 30 6 tcp listener port 155 CHICKEN User s Manual The User s Manual 30 11 tcp abandon port procedure tcp abandon port PORT Marks the socket port PORT as abandoned This is mainly useful to close down a port without breaking the connection 30 12 tcp buffer size parameter tcp buffer size Sets the size of the output buffer
139. er sequence of the form SYMBOL is encountered You can undo special handling of read syntax by passing f as the second argument if the syntax was previously defined via set read syntax Note that all of CHICKEN s special non standard read syntax is handled directly by the reader to disable built in read syntax define a handler that triggers an error for example 18 20 2 getter with setter 79 CHICKEN User s Manual The User s Manual 18 21 3 set sharp read syntax procedure set sharp read syntax CHAR OR SYMBOL PROC Similar to set read syntax but allows defining new lt CHAR gt reader syntax If the first argument is a symbol then this procedure is equivalent to set read syntax 18 21 4 set parameterized read syntax procedure set parameterized read syntax CHAR OR SYMBOL PROC Similar to set sharp read syntax but intended for defining reader syntax of the form lt NUMBER gt lt CHAR gt The handler procedure PROC will be called with two arguments the input port and the number preceding the dispatching character If the first argument is a symbol then this procedure is equivalent to set read syntax 18 21 5 copy read table procedure copy read table READ TABLE Returns a copy of the given read table You can access the currently active read table with current read table Previous Parameters Next Unit eval 18 21 3 set sharp read syntax 80 19 Unit eval This
140. es 121 209 4 16 1e BOLSEIOTE eer Ee v Ei rere ce ee boule E E 121 28 4 17 open rdohnly acta nd ore iii INTO Nee ERR REO ELTE Eds 121 ENER TEE 121 Eege 121 CHICKEN User s Manual The User s Manual Chicken User s Manual 28 Unit posix MACIAS A NN 121 28 4 21 open WEILle E 121 28 422 SS EE 121 28 4 23 Re er TE 121 DB ADA A Dare iode E ete Fee tede exe Edda tied due aset e a suse ev pede e eode ioa evo Lata 121 AR 121 25 4 26 open nonblock 5 30 rt Dee ees 121 Re e ICE E 121 20 4 28 Open SynG inde AN 122 28 4 29 A 122 25 4 30 open binaty NN 122 MAUS Oi 122 20 4 32 open imput file eer cte get ets rette iie Ebene Eden deed ee 122 Re EE 122 25 4 34 port filetio EE 122 28 5 Retrieving tile attriDUtLes uio tree P rena eee teg a nee ee ep bo edo eere pho sen eiae tue e reos pagas 122 20 9 1 WINE SAC CESS tL sees vasa e oer ert er Pre YO Eee ee roro pues eee oes Erreur de terr eren mu da FERRE TOPs 122 28 5 2 Tlile ch nge time ii ore e eere I EO EORR E PRG PEE ERR REE HERR INTO Nee danes rinde 122 28 5 5 e ne a e a EEN 123 2G D4 MESA EE 123 20 5 5 AA r ee pete ete re PL e ee Ele tetes iet ere ete Pose ee t esca ed feces acre Te loeo oe e ota 123 28 35 60 RRE 123 25 5 7 regular ii ali 123 28 6 Changing Tile gl 123 ZO EE 124 LADA e 124 28 1 Te 124 25 7 l current Process AA DEE 124 20 1 2 A A O 124 A O 124 25 7 4 DroOCESS TO A tt
141. es that are to be allocated for the secondary heap Stack holds the number of bytes for the primary heap symbols contains the size of the symbol table Passing O to one or more of these parameters will select a default size toplevel should be a pointer to the toplevel entry point procedure You should pass C_toplevel here In any subsequent call to CHICKEN run you can simply pass NULL Calling this function more than once has no effect If enough memory is available and initialization was successful then 1 is returned otherwise this function returns 0 37 3 CHICKEN run C function C word CHICKEN run void toplevel Starts the Scheme program Call this function once to execute all toplevel expressions in your compiled Scheme program If the runtime system was not initialized before then CHICKEN initialize is called with default sizes top Level is the toplevel entry point procedure you usually pass C toplevel here The result value is the continuation that can be used to re invoke the Scheme code from the point after it called return to host see below If you just need a Scheme interpreter you can also pass CHICKEN default toplevel as the toplevel procedure which just uses the default library units Once CHICKEN run has been called Scheme code is executing until all toplevel expressions have been evaluated or until return to host is called inside the Scheme program 37 Embedding 186 CHICKEN User s Manual The User s Manual 37
142. eter KEEPEMPTY is given and not f then empty substrings are retained string split one two three string split f 20 9 8 string translate procedure string translate STRING FROM TO Returns a fresh copy of STRING with characters matching FROM translated to TO If TO is omitted then matching characters are removed FROM and TO may be a character a string or a list If both FROM and TO are strings then the character at the same position in TO as the matching character in FROM is substituted 20 9 9 string translate procedure string translate STRING SMAP Substitutes elements of STRING according to SMAP SMAP should be an association list where each element of the list is a pair of the form MATCH REPLACEMENT Every occurrence of the string MATCH in STRING will be replaced by the string REPLACEMENT ng translate l gt this i en Von trainn ls h sii a Y string lt nl gt 5 T stri i isa Au t string quot 20 9 10 substringz procedure substring STRING1 STRING2 START1 START2 LENGTH procedure substring ci STRING1 STRING2 START1 START2 LENGTH Returns t if the strings STRING1 and STRING2 are equal or f otherwise The comparison starts at the positions START1 and START2 which default to 0 comparing LENGTH characters which defaults to the minimum of the remaining length of both strings 20 9 11 substring index procedure substring index WHICH WH
143. eturns t if warnings are currently enabled or f otherwise Note that this is not a parameter The current state wether warnings are enabled or disabled is global and not thread local 18 10 2 error procedure error LOCATION STRING EXP Prints error message writes all extra arguments to the value of current error port and invokes the current exception handler This conforms to SRFI 23 If LOCATION is given and a symbol it specifies the location the name of the procedure where the error occurred 18 10 3 get call chain procedure get call chain START THREAD Returns a list with the call history Backtrace information is only generated in code compiled without no trace and evaluated code If the optional argument START is given the backtrace starts at this offset i e when START is 1 the next to last trace entry is printed and so on If the optional argument THREAD is given then the call chain will only be constructed for calls performed by this thread 18 10 4 print call chain procedure print call chain PORT START THREAD Prints a backtrace of the procedure call history to PORT which defaults to current output port 18 9 3 current seconds 72 CHICKEN User s Manual The User s Manual 18 10 5 print error message procedure print error message EXN PORT STRING Prints an appropriate error message to PORT which defaults to the value of current output port for the object EXN EXN m
144. ex specifies that all matches are to be substituted string substitute 0 9 eggs chicks 2 1 99 eggs or 99 chicks 2 gt 99 eggs or chicks 99 26 11 string substitute procedure string substitute STRING SMAP MODE Substitutes elements of STRING with string substitute according to SMAP SMAP should be an association list where each element of the list is a pair of the form MATCH REPLACEMENT Every occurrence of the regular expression MATCH in STRING will be replaced by the string REPLACEMENT string substitute h1 2Hello world lt h1 gt lt A Za z0 9 gt gt Hello world 26 12 regexp escape procedure regexp escape STRING Escapes all special characters in STRING with so that the string can be embedded into a regular expression regexp escape 0 9 gt O 9 t n Previous Unit match Next Unit srfi 18 26 9 string split fields 112 27 Unit srfi 18 A simple multithreading package This threading package follows largely the specification of SRFI 18 For more information see the documentation for SRFI 18 Notes e thread start accepts a thunk a zero argument procedure as argument which is equivalent to thread start make thread THUNK e thread sleep accepts a seconds real number value in addition to a time object e When an uncaught exception i e an error is signalled in a thread other than the primordial thread
145. ext removable item 20 6 Sorting 20 6 1 merge procedure merge LIST1 LIST2 LESS procedure merge LIST1 LIST2 LESS Joins two lists in sorted order merge is the destructive version of merge LESS should be a procedure of two arguments that returns true if the first argument is to be ordered before the second argument 20 6 2 sort procedure sort SEQUENCE LESS procedure sort SEQUENCE LESS Sort SEQUENCE which should be a list or a vector Sort is the destructive version of sort 20 6 3 sorted procedure sorted SEQUENCE LESS Returns true if the list or vector SEQUENCE is already sorted 20 7 Random numbers 20 7 1 random procedure random N Returns an exact random integer from 0 to N 1 20 5 11 queue push back list 93 CHICKEN User s Manual The User s Manual 20 7 2 randomize procedure randomize X Set random number seed If X is not supplied the current time is used On startup when the extras unit is initialized the random number generator is initialized with the current time 20 8 Input Output extensions 20 8 1 make input port procedure make input port READ READY CLOSE PEEK Returns a custom input port Common operations on this port are handled by the given parameters which should be procedures of no arguments READ is called when the next character is to be read and should return a character or eof READY is called when char ready is called on this po
146. fies the pathname of the generated C file Default is FILENAME c postlude EXPRESSIONS Add EXPRESSIONS after all other toplevel expressions in the compiled file This option may be given multiple times Processing of this option takes place after processing of epi logue prelude EXPRESSIONS Add EXPRESSIONS before all other toplevel expressions in the compiled file This option may be given multiple times Processing of this option takes place before processing of prologue profile accumulate profile Instruments the source code to count procedure calls and execution times After the program terminates either via an explicit exit or implicitly profiling statistics are written to a file named PROFILE Each line of the generated file contains a list with the procedure name the number of calls and the time spent executing it Use the chicken profile program to display the profiling information in a more user friendly form Enter chicken profile with no arguments at the command line to get a list of available options The accumulate profile option is similar to profile but the resulting profile information will be appended to any existing PROFILE file chicken profile will merge and sum up the accumulated timing information if several entries for the same procedure calls exist profile name FILENAME Specifies name of the generated profile information which defaults to PROFILE Implies profile prologue FILENAME Includes the file na
147. filename or a file descriptor 28 6 2 set file position procedure set file position FILE POSITION WHENCE procedure set file position FILE POSITION Sets the current read write position of FILE to POSITION which should be an exact integer FILE should be a port or a file descriptor WHENCE specifies how the position is to interpreted and should be one of the values seek set seek cur and seek end It defaults to seek set Exceptions exn bounds exn i o file 28 7 Processes 28 7 1 current process id procedure current process id Returns the process ID of the current process 28 7 2 parent process id procedure parent process id Returns the process ID of the parent of the current process 28 7 3 process execute procedure process execute PATHNAME ARGUMENT LIST ENVIRONMENT LIST Creates a new child process and replaces the running process with it using the C library function execvp 3 If the optional argument ARGUMENT LIST is given then it should contain a list of strings which are passed as arguments to the subprocess If the optional argument ENVIRONMENT LIST is supplied then the library function execve 2 is used and the environment passed in ENVIRONMENT LIST which should be of the form lt NAME gt lt VALUE gt is given to the invoked process Note that execvp 3 respects the current setting of the PATH environment variable while execve 3 does not 28 6 1 file truncat
148. files is the main module and which is the library module An executable can only have one main module since a program has only a single entry point In this case foo scm is the main module because it doesn t have a unit declaration foo scm The declaration marks this source file as dependant on the symbols provided by the bar unit declare uses bar write fac 10 newline bar scm will be our library ii Barisan The declaration marks this source file as the bar unit The names of the units and your files don t need to match declare unit bar define fac n if zero n 1 n fac n 1 6 2 2 Compiling and running your program You should compile your two files with the following commands csc C bar scm csc C foo scm That should produce two files bar o and foo o They contain the code from your source files in compiled form To link your compiled files use the following command csc foo o bar o o foo This should produce the foo executable which you can run just as in the previous example At this point you can also erase the O files 6 2 An example with multiple files 13 CHICKEN User s Manual The User s Manual You could avoid one step and link the two files just as foo scm is compiled csc c bar scm csc foo scm bar o o foo Note that if you want to distribute your program you might want it to follow the GNU Coding Standards One relatively easy way to ach
149. fine svar x y let I yn pair y and yn caf yy case x le da v if yn v set v y M vars else etror variable not found x define lvar lambda llist body extend procedure lvar svar Here some support code that needs to be loaded at runtime glass support scm require extension lolevel define glass lambda accessor procedure data define glass lambda ref gl v procedure data gl v define glass lambda set gl v x procedure data gl v x The setup script looks like this compile s glass support scm install extension glass glass scm glass support so syntax require at runtime glass support The invocation of install extension provides the files that are to be copied into the extension repository and a metadata list that specifies that the extension g Lass is a syntax extension and that if it is declared to be used by other code either with the require extension or require for syntax form then client code should perform an implicit require glass support at startup This can be conveniently packaged as an egg 41 5 Examples for extensions 213 CHICKEN User s Manual The User s Manual tar cfz glass egg glass setup glass scm glass support scm And now we use it chicken setup glass csi quiet 1 gt require extension glass loading usr local lib chicken 1 glass scm loading usr local lib chicken 1 glass s
150. first item C SALIGN BIT Flag that specifies whether the data area of this block should be aligned on an 8 byte boundary floating point numbers for example The actual data follows immediately after the header Note that block addresses are always aligned to the native machine word boundary Scheme data objects map to blocks in the following manner pairs vector like object type bits C PAIR TYPE where the car and the cdr are contained in the first and second slots respectively vectors vector object type bits C VECTOR TYPE 42 Data Representation 218 CHICKEN User s Manual The User s Manual strings byte vector object type bits C STRING TYPE procedures special vector object type bits C CLOSURE TYPE The first slot contains a pointer to a compiled C function Any extra slots contain the free variables since a flat closure representation is used flonum a byte vector object type bits C FLONUM BITS Slots one and two or a single slot on 64 bit architectures contain a 64 bit floating point number in the representation used by the host systems C compiler symbol a vector object type bits C SYMBOL TYPE Slots one and two contain the toplevel variable value and the print name a string of the symbol respectively port a special vector object type bits C PORT TYPE The first slot contains a pointer to a file stream if this is a file pointer or NULL if not The other slots contain housekeeping data used fo
151. g Scheme procedures from C the first is to invoke the runtime function C callback with the closure to be called and the number of arguments The second is to define an externally visible wrapper function around a Scheme procedure with the define external form Note the names of all functions variables and macros exported by the CHICKEN runtime system start with C_ It is advisable to use a different naming scheme for your own code to avoid name clashes Callbacks defined by def ine externalL do not capture the lexical environment Non local exits leaving the scope of the invocation of a callback from Scheme into C will not remove the C call frame from the stack and will result in a memory leak 38 1 define external syntax define external QUALIFIERS NAME ARGUMENTTYPE1 VARIABLE1 RET syntax define external NAME TYPE INIT The first form defines an externally callable Scheme procedure NAME should be a symbol which when converted to a string represents a legal C identifier ARGUMENTTYPE1 and RETURNTYPE are foreign type specifiers for the argument variables VAR1 and the result respectively QUALIFIERS is an optional qualifier for the foreign procedure definition like stdcall define external foo c string x int string length x The second form of define external can be used to define variables that are accessible from foreign code It declares a global variable named by the symbol NAME that has the type
152. h G or g Runtime options may be combined like dC but everything following a NUMBER argument is ignored So wh64m is OK but h64mw will not enable GC of unused symbols 5 Runtime options 11 6 Examples 6 1 A simple example with one source file To compile a Scheme program assuming a UNIX like environment consisting of a single source file perform the following steps 6 1 1 Writing your source file In this example we will assume your source file is called foo scm foo scm define fac n if zero n 1 n fac n 1 write fac 10 newline 6 1 2 Compiling your program Compile the file foo scm csc foo scm This will produce the foo executable ls foo foo scm 6 1 3 Running your program To run your newly compiled executable use foo 3628800 If you geta foo command not found error you might want to try with foo instead or in Unix machines modify your PATH environment variable to include your current directory 6 Examples 12 CHICKEN User s Manual The User s Manual 6 2 An example with multiple files If multiple bodies of Scheme code are to be combined into a single executable then we have to compile each file and link the resulting object files together with the runtime system Lets consider an example where your program consists of multiple source files 6 2 1 Writing your source files The declarations in these files specify which of the compiled
153. he string FROM to the destination file or directory TO 41 4 3 install script 208 CHICKEN User s Manual The User s Manual 41 4 9 move file procedure move file FROM TO Moves the file or directory recursively given in the string FROM to the destination file or directory TO 41 4 10 remove file procedure remove file PATH Removes the file or directory given in the string PATH 41 4 11 find library procedure find library NAME PROC Returns t if the library named LiDNAME Tal so unix or NAME Lib windows could be found by compiling and linking a test program PROC should be the name of a C function that must be provided by the library If no such library was found or the function could not be resolved f is returned 41 4 12 find header procedure find header NAME Returns t if a C include file with the given name is available or f otherwise 41 4 13 try compile procedure try compile CODE key cc cflags ldflags compile only c Returns t if the C code in CODE compiles and links successfully or f otherwise The keyword parameters CC compiler name defaults to the C compiler used to build this system cf lags and Ldflags accept additional compilation and linking options If compi Le only is true then no linking step takes place If the keyword argument C is given and true then the code will be compiled in C mode 41 4 14 create directory procedure create directory PATH Create
154. hould be a bitmask composed of one or more permission values like perm irusr and is only relevant when a new file is created The default mode is perm irwxu perm irgrp perm iroth 28 4 4 file mkstemp procedure file mkstemp TEMPLATE FILENAME Create a file based on the given TEMPLATE FILENAME in which the six last characters must be XXXXXX These will be replaced with a string that makes the filename unique The file descriptor of the created file and the generated filename is returned See the mkstemp 3 manual page for details on how this function works The template string given is not modified Example usage let values fd temp path file mkstemp tmp mytemporary let temp port open output file fd format temp port This file is A 5 temp path close output port temp port 28 4 5 file read procedure file read FILENO SIZE BUFFER Reads SIZE bytes from the file with the file descriptor FILENO If a string or bytevector is passed in the optional argument BUFFER then this string will be destructively modified to contain the read data This procedure returns a list with two values the buffer containing the data and the number of bytes read 28 4 6 file select procedure file select READFDLIST WRITEFDLIST TIMEOUT 28 4 2 file close 119 CHICKEN User s Manual The User s Manual Waits until any of the file descriptors given in the lists READFDLIST and WRITEFDLIST is ready for input or out
155. ieve this is to use Autoconf and Automake two tools made for this specific purpose Consult http galinha ucpel tche br autoconf automake for some instructions on how you would do this 6 2 2 Compiling and running your program 14 7 Extending the compiler The compiler supplies a couple of hooks to add user level passes to the compilation process Before compilation commences any Scheme source files or compiled code specified using the extend option are loaded and evaluated The parameters user options pass user read pass user preprocessor pass user pass user pass 2 and user post analysis pass can be set to procedures that are called to perform certain compilation passes instead of the usual processing for more information about parameters see Supported language parameter user options pass Holds a procedure that will be called with a list of command line arguments and should return two values the source filename and the actual list of options where compiler switches have their leading hyphen removed and are converted to symbols Note that this parameter is invoked before processing of the extend option and so can only be changed in compiled user passes parameter user read pass Holds a procedure of three arguments The first argument is a list of strings with the code passed to the compiler via prelude options The second argument is a list of source files including any files specified by prologue and epilogue The third a
156. ilation one of the following happens instead e If ID names a built in features chicken srfi 23 srfi 30 srfi 39 srfi 8 srfi 6 srfi 2 srfi 0 srfi 10 srfi 9 srfi 17 srfi 55 then nothing is done e If ID names one of syntactic extensions chicken more macros chicken ffi macros then this extension will be loaded at compile time making the syntactic extensions available in compiled code e If ID names one of the core library units shipped with CHICKEN or if the option uses ID has been passed to the compiler then a declare uses ID is generated e If ID names an installed extension with the syntax or require at runtime attribute then the equivalent of require for syntax ID is performed and code is emitted to require any needed run time requirements Otherwise require extension ID is equivalent to require ID To make long matters short just use require extension and it will normally figure everything out for dynamically loadable extensions and core library units ID should be a pure extension name and should not contain any path prefixes for example dir lib is illegal ID may also be a list that designates an extension specifier Currently the following extension specifiers are defined 14 Non standard macros and special forms 31 CHICKEN User s Manual The User s Manual e srfi NUMBER is required for SRFI 55 compatibility and is fully implemented e version ID NUMBER is equivalent to ID but checks at
157. in this function returns another continuation that can be used to restart again If you invoke callbacks prior to calling CHICKEN continue make sure that the continuation is not reclaimed by garbage collection This can be avoided by using C gc protect or gc roots Another example cat x scm require extension srfi 18 define m make mutex define t mutex lock m thread sleep 1 print thread name current thread mutex unlock m t thread start make thread t PING thread start make thread t PONG let loop return to host thread yield loop cat y c include lt chicken h gt int main C word k CHICKEN run C toplevel for k CHICKEN continue k return 0 CSC x scm y c embedded It is advisable not to mix repeated uses of CHICKEN continue return to host as in the example above with callbacks Once return to host is invoked the runtime system and any Scheme code executed prior to the invocation is initialized and can be conveniently used via callbacks A simpler interface For handling GC safe references to Scheme data are the so called gc roots 37 15 CHICKEN_ continue 190 CHICKEN User s Manual The User s Manual 37 16 CHICKEN_new_gc_root C function void CHICKEN new gc root Returns a pointer to a GC root which is an object that holds a reference to a Scheme value that will always be valid even after a garbage collection The
158. ing the procedure with one argument changes its value to the value of that argument subsequent invocations with zero parameters return the new value GUARD should be a procedure of a single argument Any new values of the parameter even the initial value are passed to this procedure The guard procedure should check the value and or convert it to an appropriate form 17 2 case sensitive If true then read reads symbols and identifiers in case sensitive mode and uppercase characters in symbols are printed escaped Defaults to Ft 17 3 dynamic load libraries A list of strings containing shared libraries that should be checked for explicitly loaded library units this facility is not available on all platforms See Load Library 17 4 command line arguments Contains the list of arguments passed to this program with the name of the program and any runtime options all options starting with removed 17 Parameters 55 CHICKEN User s Manual The User s Manual 17 5 current read table A read table object that holds read procedures for special non standard read syntax see set read syntax for more information 17 6 exit handler A procedure of a single optional argument When exit is called then this procedure will be invoked with the exit code as argument The default behavior is to terminate the program 17 7 eval handler A procedure of one or two arguments When eval is invoked it calls the value of this parameter with
159. ining actual arguments are also eligible to be bound to keyword formal arguments If there is no rest formal argument and there are no keywords the it shall be an error if there are any remaining actual arguments e If key was specified in the formal argument list there shall be an even number of remaining actual arguments These are interpreted as a series of pairs where the first member of each pair is a keyword specifying the argument name and th corresponding value It shall be an error if the first member of a pair is not a keyword It shall be an error if the argument name is not the same as a variable in a keyword formal argument unless there is a rest formal argument If the same argument name occurs more than once in the list of actual arguments then the first value is used If there is no actual argument for a particular keyword formal argument then the variable is bound to the result of evaluating initializer if one was specified or f The initializer is evaluated in an environment in which all previous formal arguments have been bound It shall be an error for an lt ident gt to appear more than once in a formal argument list Example lambda x x 3 4 5 6 gt 3 45 6 lambda x y rest z z 12 Extensions to the standard 24 CHICKEN User s Manual The User s Manual 3 45 6 gt 5 6 lambda x y optional z rest r key i j 1 list x Se ij j 345 1 61 7 gt 3 45 i 6 j 1 4 1 6 set for unbo
160. inuations does not apply to explicit continuations created with call with current continuation 6 5 The second argument to eval is optional and defaults to the value of interaction environment scheme report environment and null environment accept an optional 2nd parameter if not f which is the default toplevel bindings to standard procedures are mutable and new toplevel bindings may be introduced 6 6 The tilde character is automatically expanded in pathnames Additionally if a pathname starts with VARIABLE then the prefix is replaced by the value of the given environment variable 6 6 1 if the procedures current input port and current output port are called with an argument which should be a port then that argument is selected as the new current input and output port respectively The procedures open input file open output file with input from file with output to file call with input file and call with output file accept an optional second or third argument which should be one or more keywords if supplied These arguments specify the mode in which the file is opened Possible values are the keywords text binary or append Previous Deviations from the standard Next Non standard read syntax 12 Extensions to the standard 26 13 Non standard read syntax 13 1 Multiline Block Comment A multiline block comment May be nested Implements SRFI 30 13 2 Expression Comment
161. ion 32 CHICKEN User s Manual The User s Manual 14 2 1 optional syntax optional ARGS DEFAULT Use this form for procedures that take a single optional argument If ARGS is the empty list DEFAULT is evaluated and returned otherwise the first element of the list ARGS It is an error if ARGS contains more than one value define incr x i x optional i 1 incr 10 gt 11 incr 12 5 gt 17 14 2 2 case lambda syntax case lambda LAMBDA LIST1 EXP1 Expands into a lambda that invokes the body following the first matching lambda list define plus case lambda 0 x x x y x y x y z x y z args apply args plus gt 9 plus 1 gt 1 plus 12 3 gt 6 For more information see the documentation for SRFI 16 14 2 3 let optionals syntax let optionals ARGS VAR1 DEFAULT1 BODY Binding constructs for optional procedure arguments ARGS should be a rest parameter taken from a lambda list Let optionals binds VAR1 to available arguments in parallel orto DEFAULT1 if not enough arguments were provided Let optionals binds VAR1 sequentially so every variable sees the previous ones it is an error if any excess arguments are provided let optionals one two a 1 b 2 c 3 list a b c gt one two 3 14 2 4 let optionals syntax let optionals ARGS VAR1 DEFAULT1 RESTVAR BODY 14 2 1 optional 33 C
162. it srfi 14 Character set library see the documentation for SRFI 14 On systems that support dynamic loading the srfi 14 unit can be made available in the interpreter CSi by entering require extension srfi 14 This library provides only the Latin 1 character set Previous Unit srfi 13 Next Unit match 24 Unit srfi 14 108 25 Unit match The runtime support code for the Pattern Matching extensions Note that to use the macros in normal compiled code it is not required to declare this unit as used Only if forms containing these macros are to be expanded at runtime this is needed Previous Unit srfi 14 Next Unit regex 25 Unit match 109 26 Unit regex This library unit provides support for regular expressions The regular expression package used is PCRE Perl Compatible Regular Expressions written by Philip Hazel See http www pcre org for information about the particular regexp flavor and extensions provided by this library 26 1 grep procedure grep REGEX LIST Returns all items of LIST that match the regular expression REGEX This procedure could be defined as follows define grep regex lst filter Lambda x string search regex x lst 26 2 glob gt regexp procedure glob gt regexp PATTERN Converts the file pattern PATTERN into a regular expression glob gt regexp foo zk EAA OO PATTERN should follow glob syntax Allowed wildcards are ems C1 C2 C
163. ith dos ine IOrelgm varia et or define constant or idefine inline not seen outside of the containing source file Accesses to foreign variables are translated directly into C constructs that access the variable so the Scheme name given to that variable does only exist during compile time The same goes for constant and inline definitions The name is only there to tell the compiler that this reference is to be replaced with the actual value 45 4 How does cond expand know which features are registered in used units Each unit used via declare uses is registered as a feature and so a symbol with the unit name can be tested by cond expand during macro expansion time Features registered using the register feature procedure are only available during run time of the compiled file You can use the eval when form to register features at compile time 45 5 Why are constants defined by define constant not honoured in case constructs case expands into a cascaded if expression where the first item in each arm is treated as a quoted list So the Case macro can not infer wether a symbol is to be treated as a constant name defined via 45 General 222 CHICKEN User s Manual The User s Manual define constant or a literal symbol EE How can I enable case sensitive reading writing in user code To enable the read procedure to read symbols and identifiers case sensitive you can set the parameter case sensitivity to
164. ld only be used at top level 14 4 2 define inline syntax define inline NAME VAR VAR BODY syntax define inline NAME EXP Defines an inline procedure Any occurrence of NAME will be replaced by EXP or Lambda VAR VAR BODY This is similar to a macro but variable names and scope will be correctly handled Inline substitutions take place after macro expansion EXP should be a lambda expression Any reference to NAME should appear textually after its definition Note that inline procedures are local to the current compilation unit and are not available outside of the source file in which they are defined Names of 14 3 10 receive 36 CHICKEN User s Manual The User s Manual inline procedures still exist in the Scheme namespace and can be lexically shadowed This construct is equivalent to define when evaluated or interpreted Inline definitions should only appear at toplevel 14 4 3 define macro syntax define macro NAME VAR VAR EXP1 syntax define macro NAME lambda VAR VAR EXP1 syntax define macro NAME1 NAME2 Define a globally visible macro special form The macro is available as soon as it is defined i e it is registered at compile time If the file containing this definition invokes eval and the declaration run time macros or the command line option run time macros has been used then the macro is visible in evaluated expressions during runtime The second po
165. lization argument for each slot NAME STRUCT tests any object for being an instance of this structure Slots are accessed via NAME SLOTNAME STRUCT and updated using NAME SLOTNAME set STRUCT VALUE define record point x y define pl make point 123 456 point pl gt t point x pl gt 123 point y set pl 99 point y pl gt 99 14 6 2 define record printer syntax define record printer NAME RECORDVAR PORTVAR BODY syntax define record printer NAME PROCEDURE Defines a printing method for record of the type NAME by associating a procedure with the record type When a record of this type is written using display write or print then the procedure is called with two arguments the record to be printed and an output port define record foo x y zl define f make foo 1 2 3 define record printer foo x on fprintf out foo S S S foo x x foo y x foo z x define reader ctor foo make foo define s with output to string lambda write f S gt foo 1 2 3 equal f with input from string s read gt t 14 5 3 when 38 CHICKEN User s Manual The User s Manual define record printer works also with SRFI 9 record types 14 6 3 define record type syntax define record type NAME CONSTRUCTOR TAG PREDICATE FIELD ACCESS SRFI 9 record types For more information see the documentation for SREL 9 14 7 Other forms 14 7 1 assert syntax assert
166. mbedded into the a Scheme program has 4 Compiler command line format 6 CHICKEN User s Manual The User s Manual to access the callbacks By default the prototypes are emitted after foreign declarations explicit use Disables automatic use of the units Library eval and extras Use this option if compiling a library unit instead of an application unit extend FILENAME Loads a Scheme source file or compiled Scheme program on systems that support it before compilation commences This feature can be used to extend the compiler This option may be given multiple times The file is also searched in the current include path and in the extension repository extension Mostly equivalent to prelude define extension lt NAME gt where lt NAME gt is the basename of the currently compiled file Note that if you want to compile a file as a normal dynamically loadable extension library you should also pass the Shared option feature SYMBOL Registers SYMBOL to be a valid feature identifier for cond expand fixnum arithmetic Equivalent to fixnum arithmetic declaration Assume all mathematical operations use small integer arguments heap size NUMBER Sets a fixed heap size of the generated executable to NUMBER bytes The parameter may be followed by a M m or K K suffix which stand for mega and kilobytes respectively The default heap size is 5 kilobytes Note that only half of it is in use at every given time heap initial si
167. mbol 18 6 Keywords Keywords are special symbols prefixed with that evaluate to themselves Procedures can use keywords to accept optional named parameters in addition to normal required parameters Assignment to and bindings of keyword symbols is not allowed The parameter keyword style and the compiler interpreter option keyword style can be used to allow an additional keyword syntax either compatible to Common LISP or to DSSSL 18 5 Feature identifiers 65 CHICKEN User s Manual The User s Manual 18 6 1 get keyword procedure get keyword KEYWORD ARGLIST THUNK Returns the argument from ARGLIST specified under the keyword KEYWORD If the keyword is not found then the zero argument procedure THUNK is invoked and the result value is returned If THUNK is not given f is returned define increase x args x get keyword amount args lambda 1 increase 123 gt 124 increase 123 amount 10 gt 133 Note the KEYWORD may actually be any kind of object 18 6 2 keyword procedure keyword X Returns t if X is a keyword symbol or f otherwise 18 6 3 keyword gt string procedure keyword gt string KEYWORD Transforms KEYWORD into a string 18 6 4 string gt keyword procedure string gt keyword STRING Returns a keyword with the name STRING 18 7 Exceptions CHICKEN implements the currently withdrawn SRFI 12 exception system For more information see the SRFI 12 documen
168. med FILENAME at the start of the compiled source file The include path is not searched This option may be given multiple times quiet Disables output of compile information raw Disables the generation of any implicit code that uses the Scheme libraries that is all runtime system files besides runtime c and chicken h require extension NAME Loads the extension NAME before the compilation process commences This is identical to adding require extension NAME at the start of the compiled program If uses NAME is also 4 Compiler command line format 8 CHICKEN User s Manual The User s Manual given on the command line then any occurrences of require extension NAME are replaced with declare uses NAME run time macros Makes macros also available at run time By default macros are not available at run time to stdout Write compiled code to standard output instead of creating a C file unit NAME Compile this file as a library unit Equivalent to prelude declare unit NAME unsafe Disable runtime safety checks unsafe libraries Marks the generated file for being linked with the unsafe runtime system This should be used when generating shared object files that are to be loaded dynamically If the marker is present any attempt to load code compiled with this option will signal an error uses NAME Use definitions from the library unit NAME This is equivalent to prelude declare uses NAME no usual integratio
169. mpilation unit 16 12 emit exports declaration specifier emit exports STRING Write exported toplevel variables to file with name STRING 16 7 c options 49 CHICKEN User s Manual The User s Manual 16 13 emit external prototypes first declaration specifier emit external prototypes first Emit prototypes for callbacks defined with define external before any other foreign declarations Equivalent to giving the emit external prototypes first option to the compiler 16 14 disable interrupts declaration specifier disable interrupts declaration specifier not interrupts enabled Disable timer interrupts checks in the compiled program Threads can not be preempted in main or library units that contain this declaration 16 15 disable warning declaration specifier disable warning CLASS Disable warnings of type CLASS equivalent to the disable warning CLASS compiler option 16 16 import declaration specifier import SYMBOL OR STRING Adds new imports to the list of externally available toplevel variables Arguments to this declaration may be either strings designating exports files without the file extension or symbols which directly designate imported variables 16 17 inline declaration specifier declaration specifier declaration specifier declaration specifier inline not inline inline IDENTIFIER not inline IDENTIFIER If given witho
170. n I increase the size of the trace shown when runtime errors are detected 231 S0 Opm AS E oo 232 50 1 How can I obtain smaller executables ooonnnncncnncnoncnnnnnoncccnnnonononenananonaconnnnnonnnnnanaccnnnccnoninon 232 50 2 How can I obtain faster executables coooononnnnncnccnononcnnninancccnncnnononenananincnccnnnnononnnnrccccncconononano 232 50 3 Which non standard procedures are treated specially when the extended bindings or usual integrations declaration or compiler option is used ooooonncnccccnnnnnnnnunncccnncnnononcnanininincnnnns 232 REN Le TER 234 51 1 Why does a loop that doesn t cons still trigger garbage collections 234 51 2 Why do finalizers not seem to work in simple cases in the interpeter 234 A A O A 235 52 1 Does CSI support history and autocompletiOO PT A 235 A tar ttr 236 53 1 How can I install Chicken eggs to a non default locatiOO ce eccceeseceenceeeteeeseceeeeeeeeeeeeeees 236 53 2 Can I install chicken eggs as a non root user 236 54 ACI WICH CN 237 23 eu I I 239 xxi 1 Introduction This document describes version 2 6 CHICKEN is a compiler that translates Scheme source files into C which in turn can be fed to a C compiler to generate a standalone executable An interpreter is also available and can be used as a scripting environment or for testing programs before compilation This package i
171. n setup uninstall hello2 chicken setup provides a make macro so build operations can be of arbitrary complexity When running Chicken setup with an argument NAME for which no associated file NAME setup NAME egg or NAME scm exists will ask you to download the extension via HTTP from the default URL http www call with current continuation org eggs You can use the host option to specify an alternative source location Extensions that are required to compile and or use the requested extension are downloaded and installed automatically If the given extension name contains a path prefix and the host option is given then chicken setup can also download and install eggs from an arbitrary HTTP server Alternatively you can pass a full URL including the http prefix Note that no dependency checks are done when downloading eggs directly 41 5 Examples for extensions 212 CHICKEN User s Manual The User s Manual with the URL syntax Finally a somewhat more complex example We want to package a syntax extension with additional support code that is to be loaded at run time of any Scheme code that uses that extension We create a glass lambda a procedure with free variables that can be manipulated from outside ji giass scm define macro glass lambda llist vars body Low level macros are fun let lvar gensym svar gensym x gensym y gensym yn gensym let map lambda v list v f vars de
172. nd not f then each expression is evaluated by calling this argument with the read expression as argument If TIME is given and not false then the execution time of each expression is shown as with the 19 Unit eval 81 CHICKEN User s Manual The User s Manual time macro If PRINTER is given and not false then each expression is printed before evaluation by applying the expression to the value of this argument which should be a one argument procedure 19 1 4 load library procedure load library UNIT LIBRARYFILE On platforms that support dynamic loading Load Library loads the compiled library unit UNIT which should be a symbol If the string LIBRARYFILE is given then the given shared library will be loaded and the toplevel code of the contained unit will be executed If no LIBRARYFILE argument is given then the following libraries are checked for the required unit e a file named UNIT so the files given in the parameter dynamic load libraries If the unit is not found an error is signaled When the library unit can be successfully loaded a feature identifier named UNIT is registered If the feature is already registered before loading the load library does nothing 19 1 5 set dynamic load mode procedure set dynamic load mode MODELIST On systems that support dynamic loading of compiled code via the dLopen 3 interface for example Linux and Solaris some options can be specified to fine tune the behaviour of
173. ndard output Show time needed for compilation show breakdown of time needed for each compiler pass show performed optimizations show invocation parameters show program size information and other statistics show node matching during simplification show execution of compiler sub passes show lambda lifting information show GC statistics during compilation print the line number database print every expression before macro expansion lists all unassigned global variable references lt 0 gt 353x lt 5 5 0yYynan gt 5O0 Or 4 Compiler command line format 5 CHICKEN User s Manual The User s Manual display information about experimental features when printing nodes use node tree output show the real name mapping table show expressions after the secondary user pass show database before lambda lifting pass show expressions after lambda lifting show unit information and syntax runtime requirements show source expressions show canonicalized expressions show expressions converted into CPS show database after each analysis pass show expressions after each optimization pass show expressions after each inlining pass show expressions after complete optimization show database after final analysis show expressions after closure conversion OO Y dl US UNP lt FOCZ0U0O gt debug level LEVEL Selects amount of debug information LEVEL should be an integer debug level 0 is equivalent to no trace no lambda info debug lev
174. no access to definitions in the compiled file Note also that during compile time macros are only available in the same source file in which they are defined Files included via include are considered part of the containing file 48 2 Why are macros not visible outside of the compilation unit in which they are defined Macros are defined during compile time so when a file has been compiled the definitions are gone An exception to this rule are macros defined with def ine macro which are also visible at run time i e in eval To use macros defined in other files use the include special form 48 Macros 228 49 Warnings and errors 49 1 Why does my program crash when use callback functions from Scheme to C and back to Scheme again There are two reasons why code involving callbacks can crash out of no apparent reason 1 It is important to use foreign safe lambda foreign safe Lambdat for the C code that is to call back into Scheme If this is not done than sooner or later the available stack space will be exhausted 2 If the C code uses a large amount of stack storage or if Scheme to C to Scheme calls are nested deeply then the available nursery space on the stack will run low To avoid this it might be advisable to run the compiled code with a larger nursery setting i e run the code with S anda larger value than the default for example 300k or use the nursery compiler option Note that this can decrease runtime perf
175. nos 200 40 29 C character PP TEN 200 CAO LOA EEN carer A A EA 200 40 31 C f num Ee 200 EA E iatis 201 40 33 C n m to IT 201 40 34 C TEE 201 40 3 C AN 201 GR NNEN 201 40 5 7 6 DOCK EE 201 LAST 201 GARE E 202 40 40 data POM EE 202 AQ ALC make HEADER E 202 AO AD e LEE 202 4043 symbol E E 202 AE EE E 202 40 45 OT 203 40 46 p st g NOOK TE 203 di EE A 205 41 1 Extetnston braies oco Ere EORR EO EE ERE EXEC cesedaeschepsaned AES NEE EREEREER REESE EPA ERE 205 41 2 Installing EE 205 41 3 Creating extensiofls NN 205 41 4 Procedures and macros available in setup scripts eene 206 41 41 anstallextehslOB coerente Ret Fe reor orm te ted ovde cube cO Decio Daciae ee PAYER E 206 WE See Err 207 41 4 3 mstall SCfipt cas A ete tese eta A AA E E 208 XIX CHICKEN User s Manual The User s Manual Chicken User s Manual 41 chicken setup LR AU EE 414 5 COMPING EE A ee AE Feat EE AE e EE AL AO Move RI 45 3 Why are values defined with define foreign variable or define constant or define inline not seen outside of the containing source Del 45 4 How does cond expand know which features are registered in used units 46 4 When I run csi inside an emacs buffer under Windows nothing happens 222 1222 XX CHICKEN User s Manual The User s Manual Chicken User s Manual 46 Platform specific 46 5 I load compiled code dynamically in a Windo
176. ns Specifies that standard procedures and certain internal procedures may be redefined and can not be inlined This is equivalent to declaring not usual integrations version Prints the version and some copyright information and exit the compiler verbose Prints progress information to standard output during compilation The environment variable CHICKEN OPTIONS can be set to a string with default command line options for the compiler 4 Compiler command line format 5 Runtime options After successful compilation a C source file is generated and can be compiled with a C compiler Executables generated with CHICKEN and the compiler itself accept a small set of runtime options Shows a list of the available runtime options and exits the program b Enter a read eval print loop when an error is encountered 2C Forces console mode Currently this is only used in the interpreter CSi to force output of the N gt prompt even if stdin is not a terminal for example if running in an emacs buffer under Windows d Prints some debug information at runtime D Prints some more debug information at runtime hNUMBER Specifies fixed heap size hiNUMBER Specifies the initial heap size hgPERCENTAGE Sets the growth rate of the heap in percent If the heap is exhausted then it will grow by PERCENTAGE The default is 200 hmNUMBER Specifies a maximal heap size The default is 2GB 15 hs PERCENTAGE Sets the shrink
177. ns the associated line number If line number information is not available then f is returned Note that line number information for expressions is only available in the compiler 19 3 2 macro procedure macro SYMBOL Returns t if there exists a macro definition for SYMBOL 19 3 3 macroexpand procedure macroexpand X If X is a macro form expand the macro and repeat expansion until expression is a non macro form Returns the resulting expression 19 3 4 macroexpand 1 procedure macroexpand 1 X If X is a macro form expand the macro Returns the resulting expression 19 3 5 undefine macro procedure undefine macro SYMBOL Remove the current macro definition of the macro named SYMBOL 19 2 1 repl 83 CHICKEN User s Manual The User s Manual 19 3 6 syntax error procedure syntax error LOCATION MESSAGE ARGUMENT Signals an exception of the kind exn syntax Otherwise identical to error 19 4 Loading extension libraries This functionality is only available on platforms that support dynamic loading of compiled code Currently Linux BSD Solaris Windows with Cygwin and HP UX are supported 19 4 1 repository path parameter repository path Contains a string naming the path to the extension repository which defaults to either the value of the environment variable CHICKEN REPOSITORY the value of the environment variable CHICKEN HOME or the default library path usually usr local lib
178. nt is still evaluated while the former loads it at run time 19 4 6 set extension specifier procedure set extension specifier SYMBOL PROC Registers the handler procedure PROC as a extension specifier with the name SYMBOL This facility allows extending the set of valid extension specifiers to be used with require extension When register extension is called with an extension specifier of the form SPEC and SPEC has been registered with set extension specifier then PROC will be called with two arguments the specifier and the previously installed handler or f if no such handler was defined The handler should return a new specifier that will be processed recursively If the handler returns a vector then each element of the vector will be processed recursively Alternatively the handler may return a string which specifies a file to be loaded eval when compile eval set extension specifier my package Lambda spec old make pathname my package directory gt string cadr spec require extension my package stuff gt expands into load my packag Note that the handler has to be registered at compile time if it is to be visible in compiled code 19 5 System information 19 5 1 chicken home procedure chicken home Returns a string given the installation directory usually usr local share chicken on UNIX like 19 4 5 require 85 CHICKEN User s Manual The User s Manual systems If th
179. nt of the wrong type is passed to a builtin procedure exn arithmetic Signalled on arithmetic errors like division by zero exn i o Signalled on input output errors exn i o file Signalled on file related errors exn i o net Signalled on network errors exn bounds 18 7 1 condition case 67 CHICKEN User s Manual The User s Manual Signalled on errors caused by accessing non existent elements of a collection exn runtime Signalled on low level runtime system error situations exn runtime limit Signalled when an internal limit is exceeded like running out of memory exn match Signalled on errors raised by failed matches see the section on match exn syntax Signalled on syntax errors exn breakpoint Signalled when a breakpoint is reached Notes e All error exceptions of the kind exn are non continuable e Error exceptions of the exn kind have additional arguments and Location properties that contain the arguments passed to the exception handler and the name of the procedure where the error occurred if available When the posix unit is available and used then a user interrupt signal int signals an exception of the kind user interrupt e the procedure condition property accessor accepts an optional third argument If the condition does not have a value for the desired property and if the optional argument is given no error is signalled and the accessor returns the third argument e
180. o similar to foreign lambda but the code will be executed in a primitive CPS context which means it will not actually return but call it s continuation on exit This means that code inside this form may allocate Scheme data on the C stack the nursery with C alloc see below If the RETURNTYPE is omitted it defaults to void You can return multiple values inside the body of the foreign primitive form by calling this C function C values N 2 C SCHEME UNDEFINED C k X1 where N is the number of values to be returned and X1 are the results which should be Scheme data objects When returning multiple values the return type should be omitted Previous Interface to external functions and variables Next Foreign type specifiers 34 12 foreign primitive 179 35 Foreign type specifiers Here is a list of valid foreign type specifiers 35 1 scheme object An arbitrary Scheme data object immediate or non immediate 35 2 bool As argument any value f is false anything else is true As result anything different from 0 and the NULL pointer is t 35 3 byte unsigned byte A byte 35 4 char unsigned char A character 35 5 short unsigned short A short integer number 35 6 int unsigned int int32 unsigned int32 An small integer number in fixnum range at least 30 bit 35 7 integer unsigned integer integer32 unsigned integer32 integer6 Either a fixnum or a flonum in the range of a unsigned machine
181. ocatives Note that Location X may be abbreviated as X define external foo int foreign lambda void pointer int ip ip 123 location foo foo This facility is especially useful in situations where a C function returns more than one result value gt include lt math h gt lt 39 Locations 195 CHICKEN User s Manual The User s Manual define modf foreign lambda double modf double pointer double let location i double Let f modf 1 99 location i print i i f f location returns a value of type C pointer when given the name of a callback procedure defined with define external Previous Callbacks Next Other support procedures 39 4 Other support procedures 39 5 argc argv procedure argc argv Returns two values an integer and a foreign pointer object representing the argc and argv arguments passed to the current process Previous Locations Next C interface 39 3 location 196 40 C interface The following functions and macros are available for C code that invokes Scheme or foreign procedures that are called by Scheme 40 1 C save C macro void C save C word x Saves the Scheme data object X on the temporary stack 40 2 C restore C macro void C restore Pops and returns the topmost value from the temporary stack 40 3 C fix C macro C word C fix int integer 40 4 C make character C macro C word C make character int
182. ocedure void Returns an unspecified value 18 19 Continuations 18 19 1 call cc procedure call cc PROCEDURE An alias for Call with current continuation 18 19 2 continuation capture procedure continuation capture PROCEDURE Creates a continuation object representing the current continuation and tail calls PROCEDURE with this continuation as the single argument More information about this continuation API can be found in the paper http repository readscheme org ftp papers sw2001 feeley pdf A Better API for first class Continuations by 18 17 1 vector copy TI CHICKEN User s Manual The User s Manual Marc Feeley 18 19 3 continuation procedure continuation X Returns t if X is a continuation object or f otherwise 18 19 4 continuation graft procedure continuation graft CONT THUNK Calls the procedure THUNK with no arguments and the implicit continuation CONT 18 19 5 continuation return procedure continuation return CONT VALUE Returns the value s to the continuation CONT continuation return could be implemented like this define continuation return k vals continuation graft k Lambda apply values vals 18 20 Getters SRFI 17 is fully implemented For more information see SRFI 17 18 20 1 setter procedure setter PROCEDURE Returns the setter procedure of PROCEDURE or signals an error if PROCEDURE has no associated setter procedure Note that
183. of Main is returned as the exit status to the shell Any non numeric result exits with status zero cat hi scm define main args print Hi car args 0 csi ss hi scm you Hi you 9 1 Interpreter command line format 18 CHICKEN User s Manual The User s Manual csi q l l hi scm 2 gt main list ye all i ye all dk CO ID Gh o8 EE 9 3 Toplevel commands The toplevel loop understands a number of special commands 2 Show summary of available toplevel commands J FILENAME Load files with given FILENAMEs in FILENAME Load files and print result s of each top level expression p EXP Pretty print evaluated expression EXP d EXP Describe result of evaluated expression EXP du EXP Dump contents of the result of evaluated expression EXP dur EXP N Dump N bytes of the result of evaluated expression EXP exn Describes the last exception that occurred and adds it to the result history it can be accessed using the notation 4 Quit the interpreter T Show system information S TEXT Execute shell command jt EXP Evaluate form and print elapsed time A EXP Pretty print macroexpanded expression EXP the expression is not evaluated Dr SYMBOL Enables tracing of the toplevel procedures with the given names 1 gt fac 10 gt 3628800 2 gt tr fac 3 gt fac 3 fac 3 fac 2 fac 1 fac 0 fac gt 1 fac gt 1 fac gt 2 fac gt 6 gt
184. of the result string 37 9 CHICKEN apply C macro int CHICKEN apply C word func C word args C word result Applies the procedure passed in func to the list of arguments args writing the result value to result 37 4 return to host 187 CHICKEN User s Manual The User s Manual 37 10 CHICKEN apply to string C macro int CHICKEN apply to string C word func C word args char result Applies the procedure passed in func to the list of arguments args writing a textual representation of the result into result 37 11 CHICKEN read C macro int CHICKEN read char str C word result Reads a Scheme object from the string Str writing the result value to result 37 12 CHICKEN load C macro int CHICKEN load char filename Loads the Scheme file filename either in source form or compiled 37 13 CHICKEN get error message C macro void CHICKEN get error message char result int size Returns a textual description of the most recent error that occurred in executing embedded Scheme code 37 14 CHICKEN yield C macro int CHICKEN yield int status If threads have been spawned during earlier invocations of embedded Scheme code then this function will run the next scheduled thread for one complete time slice This is useful for example inside an idle handler in a GUI application with background Scheme threads Note that the s rf 1 18 library unit has to be linked in for this An example cat x scm 155 X SCm
185. omplex real and rational are identical to the standard procedure number The procedures numerator denominator rationalize make rectangular and make polar are not implemented Support for extended numbers is available as a separate package provided the GNU multiprecision library is installed e 6 2 6 The procedure st ring gt number does not obey read write invariance on inexact numbers e 6 4 The maximum number of values that can be passed to continuations captured using call with current continuation is 120 e 6 5 Code evaluated in scheme report environment or null environment still sees non standard syntax e 6 6 2 The procedure char ready always returns t for terminal ports The procedure read does not obey read write invariance on inexact numbers e 6 6 3 The procedures write and display do not obey read write invariance to inexact numbers e 6 6 4 The transcript on and transcript off procedures are not implemented Previous Supported language Next Extensions to the standard 11 Deviations from the standard 23 12 Extensions to the standard 2 1 Identifiers may contain special characters if delimited with 2 3 The brackets are provided as an alternative syntax for A number of reader extensions is provided See Non standard read syntax 4 Numerous non standard macros are provided See Non standard macros and special forms for more information 4 1 4 Extended DSSSL s
186. or a regular expression string ACTION should be a procedure of two arguments the currently encountered file and the result of the previous invocation of ACTION or if this is the first invocation the value of IDENTITY ACTION defaults to cons IDENTITY defaults to LIMIT should a procedure of one argument that is called for each nested directory and which should return true if that directory is to be traversed recursively LIMIT may also be an exact integer that gives the maximum recursion depth A depth of O means the files in the specified directory are traversed but not any nested directories LIMIT may also be the default which is equivalent to constantly Zt Note that ACTION is called with the full pathname of each file including the directory prefix 28 18 Getting the hostname and system information 28 18 1 get host name procedure get host name Returns the hostname of the machine that this process is running on 28 18 2 system information procedure system information Invokes the UNIX system call uname and returns a list of 5 values system name node name OS release OS version and machine 28 19 Setting the file buffering mode 28 16 23 errno wouldblock 141 CHICKEN User s Manual The User s Manual 28 19 1 set buffering mode procedure set buffering mode PORT MODE BUFSIZE Sets the buffering mode for the file associated with PORT to MODE which should be one of the keywords full
187. orm is ignored and an expression resulting into an unspecified value is compiled instead The following table should make this clearer In compiled code In interpreted code eval ignore evaluate compile evaluate at compile time ignore load compile as normal ignore The situation specifiers Compile time and run time are also defined and have the same meaning as compile and Load respectively 14 7 5 include syntax include STRING Include toplevel expressions from the given source file in the currently compiled interpreted program If the included file has the extension SCm then it may be omitted The file is searched in the current directory and if not found in all directories specified in the include path option 14 7 2 cond expand 40 CHICKEN User s Manual The User s Manual 14 7 6 nth value syntax nth value N EXP Returns the Nth value counting from zero of the values returned by expression EXP 14 7 7 time syntax time EXP1 Evaluates EXP1 and prints elapsed time and some values about GC use like time spent in major GCs number of minor and major GCs Previous Non standard read syntax Next Pattern matching 14 7 6 nth value 41 15 Pattern Matching This description has been taken mostly from Andrew Wright s postscript document Pattern matching allows complicated control decisions based on data structure to be expressed in a concise manner Pattern matching is found in several mode
188. ormance on some platforms 49 2 Why does the linker complain about a missing function _C_ _toplevel This message indicates that your program uses a library unit but that the object file or library was not supplied to the linker If you have the unit foo which is contained in f 00 0 than you have to supply it to the linker like this assuming a GCC environment CSC program scm foo o o program 49 3 Why does the linker complain about a missing function _C_toplevel This means you have compiled a library unit as an application When a unit declaration as in declare unit is given then this file has a specially named toplevel entry procedure Just remove the declaration or compile this file to an object module and link it to your application code 49 4 Why does my program crash when compile a file with unsafe or unsafe declarations The compiler option unsafe or the declaration declare unsafe disable certain safety checks to improve performance so code that would normally trigger an error will work unexpectedly or even crash the running application It is advisable to develop and debug a program in safe mode without unsafe declarations and use this feature only if the application works properly 49 5 Why do I get a warning when I define a global variable named imatch Even when the match unit is not used the macros from that package are visible in the compiler The reason 49 Warnings and erro
189. ory E 115 28 VG CITE NN 116 E 116 2851 A O NO 116 DB 2 O RN ATAN 116 28 2 1 call with mput pipe eite Enes e E oE EE ER E E E NS ANE EE 116 28 2 2 Call With OUtput Pipe cisevacissccecsecciesbegssesreceseecccesdeccnnescucuusbacsoncdetanecsvschedeseabegeancddan evbeaceescaens 116 28 2 5 close mmpit pID6 ner Reo DH Re E PNEU E E T EEEE EEE ETE 116 28 2 4 ClOSE OULPUL EE 117 28 25 NO 117 LIA ET 117 28 2 7 A O 117 28 258 O EE 117 28 2 0 with imput fromr ptpe eege eege siesta yas Hn no nep o EE RE e e eue sua aen Pa svbcunsd Sn eap ade EENS 117 28 2 10 with output to pID6 iier ice terree tette tenete Ix Fn ge ede Pus ede Hg te eed ete eode vio vH eed 117 28 94 TOS tue A AL Me MD M IA russes 118 286 3 A ie oc tato erede edat ev ege ee dvo ved rp EA PELO nes CUEVA FATE vada Ere Dua EE E RS 118 PRRP A AMO 2h E 118 28 4 File descriptors and low level IC 118 28 4 1 Au pl Cate Pil eM 0 E 118 284 2 ANE Te EEN 119 25 4 3 le Open EE 119 28 44 tile mkstemp rete ee sibs rette Latine te Eee e eet d cte eae aen eaa ere erbe ee Eod oae aca 119 E E BEE 119 28 AiO le let A dia das 119 DEAT EE 120 ARO TS 120 28 4 9 ERA 120 284 10 re LE DEE 120 PNIS EE 120 284 12 NN 120 AA E m 120 PALEIS RICETTE T T T 120 28 4 15 fil no stdOUt acere eth Peter eae eos e eger os Env vus nbn eg e vededdnsadsosdnsavasiernsnadvasacsedvedadeseed cav
190. ot work in my compiled program The following piece of code does not work as expected eval when compile define reader ctor integer gt char integer gt char print integer gt char 33 The problem is that the compiler reads the complete source file before doing any processing on it so the sharp comma form is encountered before the reader ctor is defined A possible solution is to include the file containing the sharp comma form like this eval when compile define reader ctor integer gt char integer gt char include other file other file scm print integer gt char 33 49 5 Why do I get a warning when I define a global variable named match 230 CHICKEN User s Manual The User s Manual aay do built in units such as srfi 1 srfi 18 and posix fail to oad When you try to USe a built in unit such as srfi 18 you may get the following error 1 gt use srfi 18 loading library srfi 18 Error load library unable to load library srfi 18 dl Lil jj on a Mac No such file or directo Py Another symptom is that require srfi 18 will silently fail This typically happens because the Chicken libraries have been installed in a non standard location such as your home directory The workaround is to explicitly tell the dynamic linker where to look for your libraries export DYLD LIBRARY PATH scheme chicken lib DYLD LIBRARY PATH Mac export LD LIBRARY PATH
191. ou can also use the the usual integrations declaration which is identical to declaring standard bindings and extended bindings note that usual integrations is set by default Declaring block tells the compiler that global procedures are not changed outside the current compilation unit this gives the compiler some more opportunities for optimization If no floating point arithmetic is required then declaring number type fixnum can give a big performance improvement because the compiler can now inline most arithmetic operations Declaring unsafe will switch off most safety checks If threads are not used you can declare disable interrupts You should always use maximum optimizations settings for your C compiler Good GCC compiler options on Pentium and compatible hardware are Os fomit frame pointer fno strict aliasing Some programs are very sensitive to the setting of the nursery the first heap generation You should experiment with different nursery settings either by compiling with the nursery option or by using the S runtime option 50 3 Which non standard procedures are treated specially when the tlextended bindings or usual integrations declaration or compiler option is used The following standard bindings are handled specially depending on optimization options and compiler settings quotient eq eqv equal apply c r values call with values list ref null Length not char string symbol vec
192. ovided the application doesn t run out of heap space The difference between a tail and a non tail call is that the tail call has no live data after it invokes its continuation and so the amount of heap space needed stays constant 51 2 Why do finalizers not seem to work in simple cases in the interpeter Consider the following interaction in CSI 1 gt define x 1 2 3 2 gt define yammer x print x is dead 3 gt set finalizer x yammer 12 3 4 gt gc t 157812 5 gt define x f 6 gt gc Zt 157812 17 gt While you might expect objects to be reclaimed and 1 2 3 is dead printed it won t happen the literal list gets held in the interpreter history because it is the result value of the set finalizer call Running this in a normal program will work fine When testing finalizers from the interpreter you might want to define a trivial macro such as define macro v x begin print x void and wrap calls to set finalizer in it 51 Garbage collection 234 52 Interpreter 52 1 Does CSI support history and autocompletion CSI doesn t support it natively but it can be activated with the http galinha ucpel tche br readline egg After installing the egg add the following to your CSirc or equivalent file The regex egg is required for csi name of symbols starting with require readline current input port make gnu readline port gnu history install file man
193. p name the encrypted group password the group ID and a list of the names of all group members If no group with the given name or ID exists then f is returned 28 9 14 get groups procedure get groups Returns a list with the supplementary group IDs of the current user 28 9 15 set groups procedure set groups GIDLIST Sets the supplementrary group IDs of the current user to the IDs given in the list GIDLIST Only the superuser may invoke this procedure 28 9 16 initialize groups procedure initialize groups USERNAME BASEGID Sets the supplementrary group IDs of the current user to the IDs from the user with name USERNAME a string including BASEGID Only the superuser may invoke this procedure 28 9 17 perm irusr 28 9 18 perm iwusr 28 9 19 perm ixusr 28 9 13 group information 129 CHICKEN User s Manual The User s Manual 28 9 20 perm irgrp 28 9 21 perm iwgrp 28 9 22 perm ixgrp 28 9 23 perm iroth 28 9 24 perm iwoth 28 9 25 perm ixoth 28 9 26 perm irwxu 28 9 27 perm irwxg 28 9 28 perm irwxo 28 9 29 perm isvtx 28 9 30 perm isuid 28 9 31 perm isgid These variables contain permission bits as used in change file mode 28 9 32 set user id procedure set user id UID setter set current user id UID 28 9 20 perm irgrp CHICKEN User s Manual The User s Manual Sets the effective user id of the current process to UID which should be a positive integer 28 9
194. posix Unix like services e Unit utils Shell scripting and file operations e Unit tcp basic TCP sockets e Unit lolevel low level operations Previous Using the interpreter Next Interface to external functions and variables 10 Supported language 11 Deviations from the standard e Identifiers are by default case sensitive see Compiler command line format e 4 1 3 The maximal number of arguments that may be passed to a compiled procedure or macro is 120 A macro definition that has a single rest parameter can have any number of arguments If the Libf fi library is available on this platform and if it is installed then CHICKEN can take advantage of this See the README file for more details e 4 2 2 Let rec does evaluate the initial values for the bound variables sequentially and not in parallel that is letrec x 1 y 2 cons x y is equivalent to let x void y void set x 1 set y 2 cons x y where R5RS requires let x void y void let tmp1 1 tmp2 2 set x tmpl set y tmp2 cons x y e 4 3 syntax rules macros are not provided but available separately e 6 2 4 The runtime system uses the numerical string conversion routines of the underlying C library and so does only understand standard C library syntax for floating point constants e 6 2 5 There is no built in support for rationals complex numbers or extended precision integers bignums The routines c
195. print f format The FORMATSTRING can contain any sequence of characters The character prefixes special formatting directives l o write newline character N the same as S write the next argument display the next argument n skip all whitespace in the format string until the next non whitespace character B write the next argument as a binary number 0 write the next argument as an octal number X write the next argument as a hexadecimal number C write the next argument as a character display flush all pending output 20 3 Formatted output 90 CHICKEN User s Manual The User s Manual invoke formatted output routine recursively with the next two arguments as format string and list of parameters 20 4 Hash tables CHICKEN implements SRFI 69 For more information see SRFI 69 A setter for hash table ref is defined so set hash table ref HT KEY VAL 1s equivalent to hash table set HT KEY VAL As an extension to SRFI 69 hash table update and hash table update default return the new value after applying the update procedure 20 5 Queues 20 5 1 list gt queue procedure list gt queue LIST Returns LIST converted into a queue where the first element of the list is the same as the first element of the queue The resulting queue may share memory with the list and the list should not be modified after this operation 20 5 2 make queue proce
196. procedure string chop STRING LENGTH Returns a list of substrings taken by chopping STRING every LENGTH characters string chop one two three 4 gt one two thre e 20 9 4 string chomp procedure string chomp STRING SUFFIX If STRING ends with SUFFIX then this procedure returns a copy of its first argument with the suffix removed otherwise returns STRING unchanged SUFFIX defaults to An 20 9 5 string compare3 procedure string compare3 STRING1 STRING2 procedure string compare3 ci STRING1 STRING2 Perform a three way comparison between the STRING1 and STRING2 returning either 1 if STRING is lexicographically less than STRING2 0 if it is equal or 1 if it s greater st ring Compare3 ci performs a case insensitive comparison 20 9 6 string intersperse procedure string intersperse LIST STRING Returns a string that contains all strings in LIST concatenated together STRING is placed between each concatenated string and defaults to string intersperse one two three is equivalent to apply string append intersperse one two three 20 9 2 gt string 97 CHICKEN User s Manual The User s Manual 20 9 7 string split procedure string split STRING DELIMITER STRING KEEPEMPTY Split string into substrings separated by the given delimiters If no delimiters are specified a string comprising the tab newline and space characters is assumed If the param
197. pt gt 20 10 6 disjoin procedure disjoin PRED Returns a procedure that returns t if its argument satisfies any predicate PRED lt enscript highlight scheme gt disjoin odd positive 32 t disjoin odd positive 32 f lt enscript gt 20 10 7 each procedure each PROC Returns a procedure that applies PROC to its arguments and returns the result s of the last procedure application For example each pp eval is equivalent to Lambda args apply pp args apply eval args each PROC is equivalent to PROC and each is equivalent to noop 20 10 8 flip procedure flip PROC Returns a two argument procedure that calls PROC with its arguments swapped lt enscript highlight scheme gt flip PROC lambda x y PROC y x lt enscript gt 20 10 9 identity procedure identity X Returns its sole argument X 20 10 5 conjoin 100 CHICKEN User s Manual The User s Manual 20 10 10 project procedure project N Returns a procedure that returns its Nth argument starting from 0 20 10 11 list of procedure list of PRED Returns a procedure of one argument that returns t when applied to a list of elements that all satisfy the predicate procedure PRED or f otherwise list of even 1 2 3 gt f list of number 1 2 3 gt st 20 10 12 noop procedure noop X Ignores it s arguments does nothing and returns an unspecified value 20 10
198. put respectively If the optional argument TIMEOUT is given and not false then it should specify the number of seconds after which the wait is to be aborted This procedure returns two values the lists of file descriptors ready for input and output respectively READFDLIST and WRITEFDLIST may also by file descriptors instead of lists In this case the returned values are booleans indicating whether input output is ready by t or f otherwise You can also pass f as READFDLIST or WRITEFDLIST argument which is equivalent to 28 4 7 file write procedure file write FILENO BUFFER SIZE Writes the contents of the string or bytevector BUFFER into the file with the file descriptor FILENO If the optional argument SIZE is given then only the specified number of bytes are written 28 4 8 file control procedure file control FILENO COMMAND ARGUMENT Performs the fcntl operation COMMAND with the given FILENO and optional ARGUMENT The return value is meaningful depending on the COMMAND 28 4 9 fcntl dupfd 28 4 10 fcntl getfd 28 4 11 fcntl setfd 28 4 12 fcntl getfl 28 4 13 fcntl setfl These variables contain commands for file control 28 4 14 fileno stdin 28 4 6 file select 120 CHICKEN User s Manual The User s Manual 28 4 15 fileno stdout 28 4 16 fileno stderr These variables contain file descriptors for the standard I O files 28 4 17 open rdonly 28 4 18 open wronly 28 4 19 open rdwr 28 4 20 open
199. put into a file and passing the file via the t ree option to chicken setup allows you now to use the local repository file Retrieve complete extension repository big cd opt svn co https galinha ucpel tche br svn chicken eggs Get your own copy of the repository file chicken setup fetch tree gt my repository file Now you can install eggs from your local checkout with full dependency tracking and without being connected to the internet cd tmp chicken setup local opt eggs chicken eggs tree my repository file opengl 41 10 Linking extensions statically The compiler and chicken setup support statically linked eggs The general approach is to generate an object file or static library in addition to the usual shared library in your Setup script and install it along with the dynamically loadable extension The setup properties Static should contain the name of the object file or static library to be linked when CSC gets passed the static extensions option compile s 02 d1 my ext scm dynamically loadable normal version 41 8 Security 216 CHICKEN User s Manual The User s Manual compile c 02 dl my ext unit my ext statically linkable version install extension my ext my ext so my ext o static my ext o Note the use of the unit option in the second compilation step static linking must use static library units chicken setup will perform platform dependent file
200. r C word x 40 32 C c string 201 CHICKEN User s Manual The User s Manual 40 39 C u i car C macro C word C u i car C word x Aliases for C block item x 0 andC block item x 1 respectively 40 40 C data pointer C macro void C data pointer C word x Returns a pointer to the data section of a non immediate Scheme object 40 41 C make header C macro C word C make header C word bits C word size A macro to build a Scheme object header from its bits and size parts 40 42 C mutate C function C word C mutate C word slot C word val Assign the Scheme value val to the location specified by slot If the value points to data inside the nursery the first heap generation then the garbage collector will remember to handle the data appropriately Assigning nursery pointers directly will otherwise result in lost data Note that no copying takes place at the moment when C mutate is called but later at the next minor garbage collection 40 43 C symbol value C macro C word C symbol value C word symbol Returns the global value of the variable with the name symbol If the variable is unbound C SCHEME UNBOUND is returned You can set a variable s value with C mutate amp C symbol value SYMBOL VALUE 40 44 C gc protect C function void C gc protect C word ptrs int n Registers n variables at address ptrs to be garbage collection roots The locations should not contain pointers to data alloca
201. r each line 152 CHICKEN User s Manual The User s Manual Similar to system sprintf FORMATSTRING ARGUMENT1 but signals an error if the invoked program should return a nonzero exit status 29 7 Reading a file s contents 29 7 1 read all procedure read all FILE OR PORT If FILE OR PORT is a string then this procedure returns the contents of the file as a string If FILE OR PORT is a port all remaining input is read and returned as a string The port is not closed If no argument is provided input will be read from the port that is the current value of current input port 29 8 Miscellaneous handy things 29 8 1 shift procedure shift LIST DEFAULT Returns the car of LIST or DEFAULT if LIST is empty and replaces the car of LIST with it s cadr and the cdr with the cddr If DEFAULT is not given and the list is empty f is returned An example might be clearer here define lst 1 2 3 shift lst gt 1 lst is now 2 3 The list must at least contain 2 elements 29 8 2 unshift procedure unshift X PAIR Sets the car of PAIR to X and the cdr to its cddr Returns PAIR define lst 2 unshift 99 lst lst is now 99 2 Previous Unit posix Next Unit tcp 29 6 1 system 153 30 Unit tcp This unit provides basic facilities for communicating over TCP sockets The socket interface should be mostly compatible to the one found in PLT Scheme This unit uses the extras unit
202. r this port structure a vector object type bits C STRUCTURE TYPE The first slot contains a symbol that specifies the kind of structure this record is an instance of The other slots contain the actual record items pointer a special vector object type bits C POINTER TYPE The single slot contains a machine pointer tagged pointer similar to a pointer type bits C TAGGED POINTER TYPE but the object contains an additional slot with a tag an arbitrary data object that identifies the type of the pointer Data objects may be allocated outside of the garbage collected heap as long as their layout follows the above mentioned scheme But care has to be taken not to mutate these objects with heap data i e non immediate objects because this will confuse the garbage collector For more information see the header file chicken bh Previous chicken setup Next Bugs and limitations 42 Data Representation 219 43 Bugs and limitations Compiling large files takes too much time e If a known procedure has unused arguments but is always called without those parameters then the optimizer repairs the procedure in certain situations and removes the parameter from the lambda list e port position currently works only for input ports Leaf routine optimization can theoretically result in code that thrashes if tight loops perform excessively many mutations Previous Data representation Next FAQ 43 Bugs and limitations 220
203. rate of the heap in percent If no more than a quarter of PERCENTAGE of the heap is used then it will shrink to PERCENTAGE The default is 50 Note If you want to make sure that the heap never shrinks specify a value of H this can be useful in situations where an optimal heap size is known in advance 10 Disables detection of stack overflows at run time SNUMBER Specifies stack size tNUMBER Specifies symbol table size FNUMBER Specifies the maximal number of currently pending finalizers before finalization is forced aNUMBER Specifies the length of the buffer for recording a trace of the last invoked procedures Defaults to 16 iW Enables garbage collection of unused symbols By default unused and unbound symbols are not garbage collected P Writes trace output to stderr This option has no effect with in files compiled with the no trace options iX Raises uncaught exceptions of separately spawned threads in primordial thread By default uncaught exceptions in separate threads are not handled unless the primordial one explicitly joins them When warnings are enabled the default and X is not given a warning will be shown though B Sounds a bell ASCII 7 on every major garbage collection The argument values may be given in bytes in kilobytes suffixed with K or k in megabytes suffixed with M 5 Runtime options 10 CHICKEN User s Manual The User s Manual or M or in gigabytes suffixed wit
204. rce code If the extension of the source file is SCM it may be omitted The runtime options described in Compiler command line format are also available for the interpreter If the environment variable CSI OPTIONS is set to a list of options then these options are additionally passed to every direct or indirect invocation of CSi Please note that runtime options like can not be passed using this method The options recognized by the interpreter are Ignore everything on the command line following this marker Runtime options are still recognized i case insensitive Enables the reader to read symbols case insensitive The default is to read case sensitive in violation of R5RS This option registers the Case insensitive feature identifier b batch Quit the interpreter after processing all command line options e eval EXPRESSIONS Evaluate EXPRESSIONS This option implies batch and quiet so no startup message will be printed and the interpreter exits after processing all eval options and or loading files given on the command line D feature SYMBOL Registers SYMBOL to be a valid feature identifier for cond expand h help Write a summary of the available command line options to standard output and exit I include path PATHNAME Specifies an alternative search path for files included via the include special form This option may be given multiple times If the environment variable CHICKEN INCLUDE PATH is set i
205. rec and match define should not be used in computing the bound value The match match Lambda and mat ch Lambda forms allow the optional syntax gt identifier between the pattern and the body of a clause When the pattern match for such a clause succeeds the identifier is bound to a failure procedure of zero arguments within the body If this procedure is invoked it jumps back to the pattern matching expression and resumes the matching process as if the pattern had failed to match The body must not mutate the object being matched otherwise unpredictable behavior may result 15 2 Patterns identifier excluding the reserved names and or not set get and Kfor non negative integers K matches anything and binds a variable of this name to the matching value in the body _ matches anything without binding any variables t f string number character s expression These constant patterns match themselves i e the corresponding value must be equal to the pattern pat 1 pat n matches a proper list of n elements that match pat 1 through pat n pat 1 pat n pat n 1 matches a possibly improper list of at least n elements that ends in something matching pat n 1 pat 1 pat n pat n 1 matches a proper list of n or more elements where each element of the tail matches pat n 1 Each pattern variable in pat n 1 is bound to a list of the matching values For example
206. rectly passed as arguments to foreign function neither can they be result values Pointers to unions are allowed though 35 23 const TYPE 183 CHICKEN User s Manual The User s Manual 35 31 instance CNAME SCHEMECLASS A pointer to a C class instance CNAME should designate the name of the C class and SCHEMECLASS should be the class that wraps the instance pointer Normally SCHEMECLASS should be a subclass of lt c object gt 35 32 instance ref CNAME SCHEMECLASS A reference to a C class instance 35 33 function RESULTTYPE ARGUMENTTYPE CALLCONV A function pointer CALLCONV specifies an optional calling convention and should be a string The meaning of this string is entirely platform dependent The value f is also allowed and is passed as a NULL pointer 35 31 instance CNAME SCHEMECLASS 184 36 Mappings Foreign types are mapped to C types in the following manner bool unsigned char unsigned short unsigned int unsigned integer unsigned long float double number nonnull pointer nonnull c pointer nonnull byte vector nonnull u8vector nonnull s8vector nonnull ul6vector nonnull s16vector nonnull u32vector nonnull s32vector nonnull f32vector nonnull f64vector nonnull c string symbol void nonnull pointer TYPE enum NAME struct NAME ref TYPE template T1 T2 union NAME function RTYPE ATYPE CALLCONV instance C
207. regular expression wrapped in 26 7 string search 26 8 string search positions procedure string search REGEXP STRING START RANGE procedure string search positions REGEXP STRING START RANGE Searches for the first match of the regular expression in REGEXP with STRING The search can be limited to RANGE characters 26 9 string split fields procedure string split fields REGEXP STRING MODE START Splits STRING into a list of fields according to MODE where MODE can be the keyword inf ix REGEXP matches field separator the keyword suf f ix REGEXP matches field terminator or t REGEXP matches field which is the default define s this is a string 1 2 3 string split fields s this is a string 1 2 3 string split fields s infix gt this ig a string 1 2 3 26 4 regexp 111 CHICKEN User s Manual The User s Manual string split fields s suffix gt this is a string 1 2 3 26 10 string substitute procedure string substitute REGEXP SUBST STRING MODE Searches substrings in STRING that match REGEXP and substitutes them with the string SUBST The substitution can contain references to subexpressions in REGEXP with the NNUM notation where NUM refers to the NUMth parenthesized expression The optional argument MODE defaults to 1 and specifies the number of the match to be substituted Any non numeric ind
208. rgument is a list of strings specified using postlude options The procedure should return a list of toplevel Scheme expressions parameter user preprocessor pass Holds a procedure of one argument This procedure is applied to each toplevel expression in the source file before macro expansion The result is macro expanded and compiled in place of the original expression parameter user pass Holds a procedure of one argument This procedure is applied to each toplevel expression after macro expansion The result of the procedure is then compiled in place of the original expression parameter user pass 2 Holds a procedure of three arguments which is called with the canonicalized node graph as its sole argument The result is ignored so this pass has to mutate the node structure to cause any effect parameter user post analysis pass Holds a procedure that will be called after the last performed program analysis The procedure when defined will be called with three arguments the program database a getter and a setter procedure which can be used to access and manipulate the program database which holds various information about the compiled program The getter procedure should be called with two arguments a symbol representing the binding for which information should be retrieved and a symbol that specifies the database entry The current value of the database entry will be returned or f if no such entry is available The setter procedure is
209. rguments that accesses the corresponding field of the matching value This pattern is the complement to set As with set this pattern must be nested within a pair vector box or structure pattern Quasipatterns Quasiquote introduces a quasipattern in which identifiers are considered to be symbolic constants Like Scheme s quasiquote for data unquote and unquote splicing escape back to normal patterns 15 3 Match Failure If no clause matches the value the default action is to invoke the procedure match error procedure with the value that did not match The default definition of match error procedure calls error 15 3 Match Failure 45 CHICKEN User s Manual The User s Manual with an appropriate message 1 gt match 1 2 2 Failed match Error no matching clause for 1 For most situations this behavior is adequate but it can be changed by altering the value of the parameter match error control procedure match error control match error control MODE Selects a mode that specifies how match macro forms are to be expanded With no argument this procedure returns the current mode A single argument specifies the new mode that decides what should happen if no match clause applies The following modes are supported Signal an error This is the default 1 error Signal an error and output the offending form 1 match Omits pair tests when the consequence is to fail in Car or Cdr rather
210. rm can be used in the position of an ordinary Lambda expression NAME specifies the name of the external procedure and should be a string or a symbol 34 9 foreign lambda syntax foreign lambda RETURNTYPE ARGTYPE VARIABLE STRING Similar to foreign lambda but instead of generating code to call an external function the body of the C procedure is directly given in STRING define my strlen foreign lambda int c string str int n 0 while str n C return n C yi my strlen one two three gt 13 For obscure technical reasons you should use the C_ return macro instead of the normal return statement to return a result from the foreign lambda body as some cleanup code has to be run before execution commences in the calling code 34 10 foreign safe lambda syntax foreign safe lambda RETURNTYPE NAME ARGTYPE This is similar to foreign Lambda but also allows the called function to call Scheme functions and allocate Scheme data objects See Callbacks 34 11 foreign safe lambda syntax foreign safe lambda RETURNTYPE ARGTYPE VARIABLE STRING This is similar to foreign lambda but also allows the called function to call Scheme functions and allocate Scheme data objects See Callbacks 34 7 define foreign enum 178 CHICKEN User s Manual The User s Manual 34 12 foreign primitive syntax foreign primitive RETURNTYPE ARGTYPE VARIABLE STRING This is als
211. rn languages notably Standard ML Haskell and Miranda These syntactic extensions internally use the match library unit The basic form of pattern matching expression is match exp pat body where exp is an expression pat is a pattern and body is one or more expressions like the body of a lambda expression The match form matches its first subexpression against a sequence of patterns and branches to the body corresponding to the first pattern successfully matched For example the following code defines the usual map function define map Lambda f l match L 0 0 x y cons f x map f y 1 The first pattern matches the empty list The second pattern X y matches a pair binding X to the first component of the pair and y to the second component of the pair 15 1 Pattern Matching Expressions The complete syntax of the pattern matching expressions follows exp match exp clause match lambda clause match lambda clause match let pat exp body match let pat exp body match letrec pat exp body match let var pat exp body match define pat exp clause pat body pat gt identifier body pat identifier matches anything and binds identifier as a variab I anything itself the empty list t itself f itself string an equal string number an equal number character an equal character s e
212. rocedure pathname extension PATHNAME Accessors for the components of PATHNAME If the pathname does not contain the accessed component then f is returned 29 2 8 pathname replace directory procedure pathname replace directory PATHNAME DIRECTORY 29 2 9 pathname replace file procedure pathname replace file PATHNAME FILENAME 29 2 3 make pathname 150 CHICKEN User s Manual The User s Manual 29 2 10 pathname replace extension procedure pathname replace extension PATHNAME EXTENSION Return a new pathname with the specified component of PATHNAME replaced by a new value 29 2 11 pathname strip directory procedure pathname strip directory PATHNAME 29 2 12 pathname strip extension procedure pathname strip extension PATHNAME Return a new pathname with the specified component of PATHNAME stripped 29 3 Temporary files 29 3 1 create temporary file procedure create temporary file EXTENSION Creates an empty temporary file and returns its pathname If EXTENSION is not given then tmp is used If the environment variable TMPDIR TEMP or TMP is set then the pathname names a file in that directory 29 4 Deleting a file without signalling an error 29 4 1 delete file procedure delete file FILENAME If the file FILENAME exists it is deleted and t is returned If the file does not exist nothing happens and f is returned 29 5 Iterating over input lines and files 29 2 10 pathname replace e
213. rs 229 CHICKEN User s Manual The User s Manual for this is that macros can not be accessed from library units only when explicitly evaluated in running code To speed up macro expansion time the compiler and the interpreter both already provide the compiled match macro definitions Macros shadowed lexically are no problem but global definitions of variables named identically to global macros are useless the macro definition shadows the global variable This problem can be solved using a different name or undefining the macro like this eval when compile eval undefine macro match 49 6 Why don t toplevel continuations captured in interpreted code work Consider the following piece of code define k call with current continuation lambda k k k k When compiled this will loop endlessly But when interpreted k k will return to the read eval print loop This happens because the continuation captured will eventually read the next toplevel expression from the standard input or an input file if loading from a file At the moment K was defined the next expression was k k But when k is invoked the next expression will be whatever follows after k k In other words invoking a captured continuation will not rewind the file position of the input source A solution is to wrap the whole code into a begin expression so all toplevel expressions will be loaded together 49 7 Why does define reader ctor n
214. rt and should return t or f CLOSE is called when the port is closed PEEK is called when peek char is called on this port and should return a character or eof if the argument PEEK is not given then READ is used instead and the created port object handles peeking automatically by calling READ and buffering the character 20 8 2 make output port procedure make output port WRITE CLOSE FLUSH Returns a custom output port Common operations on this port are handled by the given parameters which should be procedures WRITE is called when output is sent to the port and receives a single argument a string CLOSE is called when the port is closed and should be a procedure of no arguments FLUSH if provided is called for flushing the output port 20 8 3 pretty print procedure pretty print EXP PORT procedure pp EXP PORT Print expression nicely formatted PORT defaults to the value of current output port 20 8 4 pretty print width Parameter Specifies the maximal line width for pretty printing after which line wrap will occur 20 7 2 randomize 94 CHICKEN User s Manual The User s Manual 20 8 5 read file procedure read file FILE OR PORT READER MAXCOUNT Returns a list containing all toplevel expressions read from the file or port FILE OR PORT If no argument is given input is read from the port that is the current value of current input port After all expressions are read and if the arg
215. s Next Unit library 17 13 reset handler 57 18 Unit library This unit contains basic Scheme definitions This unit is used by default unless the program is compiled with the explicit use option 18 1 Arithmetic 18 1 1 add1 18 1 2 sub1 procedure add1 N procedure sub1 N Adds subtracts 1 from N 18 1 3 bitwise and 18 1 4 bitwise ior 18 1 5 bitwise xor 18 1 6 bitwise not 18 1 7 arithmetic shift procedure bitwise and N1 procedure bitwise ior N1 procedure bitwise xor N1 procedure bitwise not N procedure arithmetic shift N1 N2 Binary integer operations arithmetic shift shifts the argument N1 by N2 bits to the left If N2 is negative than N1 is shifted to the right These operations only accept exact integers or inexact integers in word range 32 bit signed on 32 bit platforms or 64 bit signed on 64 bit platforms 18 Unit library 58 CHICKEN User s Manual The User s Manual 18 1 8 bit set procedure bit set N INDEX Returns t if the bit at the position INDEX in the integer N is set or f otherwise The rightmost least significant bit is bit 0 18 1 9 fixnum procedure fixnum X Returns t if X is a fixnum or Af otherwise 18 1 10 fx 18 1 11 fx 18 1 12 fx 18 1 13 fx 18 1 14 fxmod 18 1 15 fxneg 18 1 16 fxmin 18 1 17 fxmax 18 1 18 fx 18 1 8 bit set 59 CHICKEN User s Manual The User s Manual 18 1 19 fx gt
216. s a locative that refers to the element of the non immediate object EXP at position INDEX EXP may be a vector pair string byte vector SRFI 4 number vector or record INDEX should be a fixnum INDEX 32 5 3 object evicted 167 CHICKEN User s Manual The User s Manual defaults to 0 32 6 2 make weak locative procedure make weak locative EXP INDEX Creates a weak locative Even though the locative refers to an element of a container object the container object will still be reclaimed by garbage collection if no other references to it exist 32 6 3 locative procedure locative X Returns t if X is a locative or f otherwise 32 6 4 locative ref procedure locative ref LOC Returns the element to which the locative LOC refers If the containing object has been reclaimed by garbage collection an error is signalled 32 6 5 locative set procedure locative set LOC X procedure set locative ref LOC X Changes the element to which the locative LOC refers to X If the containing object has been reclaimed by garbage collection an error is signalled 32 6 6 locative gt object procedure locative gt object LOC Returns the object that contains the element referred to by LOC or f if the container has been reclaimed by garbage collection 32 7 Accessing toplevel variables 32 6 1 make locative 168 CHICKEN User s Manual The User s Manual 32 7 1 global bound procedure global bound
217. s as the type of a return value a NULL pointer will be returned as f 35 15 nonnull c pointer As C pointer but guaranteed not to be f NULL 35 9 float double 181 CHICKEN User s Manual The User s Manual 35 16 scheme or c pointer An untyped pointer If the argument is a machine pointer object the wrapped C pointer will be passed If it is any other object then this type is treated as scheme pointer Not allowed as a result type 35 17 nonnull byte vector A byte vector object passed as a pointer to its contents Arguments of type byte vector may optionally be f which is passed as a NULL pointer This is not allowed as a return type 35 18 nonnull u8vector nonnull u16vector nonnull u32vector nonnull s8vector nonnull s16vector nonnull s32vector Wei f32vector nonnull f64vector A SRFI 4 number vector object passed as a pointer to its contents Arguments of type byte vector may optionally be f which is passed as a NULL pointer These are not allowed as return types 35 19 c string A C string zero terminated The value f is also allowed and is passed as a NULL pointer If uses as the type of a return value a NULL pointer will be returned as f Note that the string is copied with a zero byte appended when passed as an argument to a foreign function Also a return value of this type is copied into garbage collected memory 35 20 nonnull c string As C String but guaranteed not to be f N
218. s distributed under the BSD license and as such is free to use and modify The method of compilation and the design of the runtime system follow closely Henry Baker s CONS Should Not CONS Its Arguments Part II Cheney on the M T A paper and expose a number of interesting properties e Consing creation of data on the heap is relatively inexpensive because a generational garbage collection scheme is used in which short lived data structures are reclaimed extremely quickly e Moreover call with current continuation is practically for free and CHICKEN does not suffer under any performance penalties if first class continuations are used in complex ways The generated C code is fully tail recursive Some of the features supported by CHICKEN e SRFIs 0 1 2 4 6 19 23 25 31 37 40 42 43 45 47 55 57 60 63 66 69 72 78 85 and 95 e Lightweight threads based on first class continuations e Pattern matching with Andrew Wright s match package e Record structures e Extended comment and string literal syntaxes e Libraries for regular expressions string handling e UNIX system calls and extended data structures e Create interpreted or compiled shell scripts written in Scheme for UNIX or Windows Compiled C files can be easily distributed e Allows the creation of fully self contained statically linked executables e On systems that support it compiled code can be loaded dynamically This manual is merely a reference for the CHICKE
219. s either a machine pointer or an integer as argument and returns a new pointer or integer aligned to the native word size of the host platform 32 2 Tagged pointers Tagged pointers are foreign pointer objects with an extra tag object 32 2 1 tag pointer procedure tag pointer PTR TAG Creates a new tagged pointer object from the foreign pointer PTR with the tag TAG which may an arbitrary Scheme object 32 1 25 pointer s32 set 162 CHICKEN User s Manual The User s Manual 32 2 2 tagged pointer procedure tagged pointer X TAG Returns t if X is a tagged pointer object with the tag TAG using an eq comparison or f otherwise 32 2 3 pointer tag procedure pointer tag PTR If PTR is a tagged pointer object its tag is returned If PTR is a normal untagged foreign pointer object f is returned Otherwise an error is signalled 32 3 Extending procedures with data 32 3 1 extend procedure procedure extend procedure PROCEDURE X Returns a copy of the procedure PROCEDURE which contains an additional data slot initialized to X If PROCEDURE is already an extended procedure then its data slot is changed to contain X and the same procedure is returned 32 3 2 extended procedure procedure extended procedure PROCEDURE Returns t if PROCEDURE is an extended procedure or f otherwise 32 3 3 procedure data procedure procedure data PROCEDURE Returns the data object contained in the extended proc
220. s the directory given in the string PATH with all parent directories as needed 41 4 9 move file 209 CHICKEN User s Manual The User s Manual 41 4 15 installation prefix parameter installation prefix Holds the prefix under which CHICKEN executables and libraries have been installed either the value of the environment variable CHICKEN PREFIX or whatever prefix was specified at the time the system was built 41 4 16 program path parameter program path PATH Holds the path where executables are installed and defaults to either CHICKEN_PREFIX bin if the environment variable CHICKEN PREFIX is set CHICKEN_ HOME or the path where the CHICKEN binaries chicken csi etc are installed 41 4 17 setup root directory parameter setup root directory PATH Contains the path of the directory where chicken setup was invoked 41 4 18 setup build directory parameter setup build directory PATH Contains the path of the directory where the extension is built This is not necessarily identical to setup root directory 41 4 19 setup verbose flag parameter setup verbose flag BOOL Reflects the setting of the verbose option i e is t if verbose was given 41 4 20 setup install flag parameter setup install flag BOOL Reflects the setting of the no install option i e is f if no install was given 41 4 15 installation prefix 210 CHICKEN User s Manual The User s Manual 41 4 21 r
221. s8vector length ul6vector length sl6vector length u32vector length s32vector length f32vector length f64vector length u8vector ref s8vector ref ul6vector ref sl6vector ref u32vector ref s32vector ref f32vector ref f64vector ref u8vector set s8vector set ul6vector set sl6vector set u32vector set s32vector set hash table ref block set number of slots first second third fourth null pointer pointer gt object make record instance locative ref locative set locative locative gt object identity cpu time error call cc any 50 3 Which non standard procedures are treated specially whenthe extended bindings or usual integt3fions d 51 Garbage collection 51 1 Why does a loop that doesn t cons still trigger garbage collections Under CHICKENs implementation policy tail recursion is achieved simply by avoiding to return from a function call Since the programs is CPS converted a continuous sequence of nested procedure calls is performed At some stage the stack space has to run out and the current procedure and its parameters including the current continuation are stored somewhere in the runtime system Now a minor garbage collection occurs and rescues all live data from the stack the first heap generation and moves it into the the second heap generation Than the stack is cleared using a Longjmp and execution can continue from the saved state With this method arbitrary recursion in tail or non tail position can happen pr
222. safe option Also implies declare no bound checks no procedure checks no argc checks 16 35 uses declaration specifier uses SYMBOL Gives a list of used library units Before the toplevel expressions of the main module are executed all used 16 30 standard bindings 53 CHICKEN User s Manual The User s Manual units evaluate their toplevel expressions in the order in which they appear in this declaration If a library unit A uses another unit B then B s toplevel expressions are evaluated before A s Furthermore the used symbols are registered as features during compile time so cond expand knows about them Previous Pattern matching Next Parameters 16 35 uses 54 17 Parameters Certain behavior of the interpreter and compiled programs can be customized via parameters where a parameter is a procedure of zero or one arguments To retrieve the value of a parameter call the parameter procedure with zero arguments To change the setting of the parameter call the parameter procedure with the new value as argument define foo make parameter 123 foo gt 123 foo 99 foo gt 99 Parameters are fully thread local each thread of execution owns a local copy of a parameters value CHICKEN implements SRFI 39 17 1 make parameter procedure make parameter VALUE GUARD Returns a procedure that accepts zero or one argument Invoking the procedure with zero arguments returns VALUE Invok
223. se Previous Extensions to the standard Next Non standard macros and special forms 13 14 Conditional Expansion 30 14 Non standard macros and special forms 14 1 Making extra libraries and extensions available 14 1 1 require extension syntax require extension ID syntax use ID This form does all necessary steps to make the libraries or extensions given in ID available It loads syntactic extension if needed and generates code for loading linking with core library modules or separately installed extensions US is just a shorter alias for require extension This implementation of require extension is compliant to SRFI 55 see the SRFI 55 document for more information During interpretation evaluation requi re extension performs one of the following e If ID names a built in features chicken srfi 23 srfi 30 srfi 39 srfi 8 srfi 6 srfi 2 srfi 0 srfi 10 srfi 9 srfi 17 srfi 55 then nothing is done e If ID names one of syntactic extensions chicken more macros chicken ffi macros then this extension will be loaded e ID names one of the core library units shipped with CHICKEN then a Load library ID will be performed e ID names an installed extension with the syntax or require at runtime attribute then the equivalent of require for syntax ID is performed probably followed by require for any run time requirements Otherwise require extension ID is equivalent to require ID During comp
224. setup hello 41 4 21 required chicken version 211 CHICKEN User s Manual The User s Manual at the shell prompt and in the same directory where the two files exist the file hello scm will be compiled into a dynamically loadable library If the compilation succeeds hel lo SO will be stored in the repository together with a file named hello setup info containing an a list with metadata If no extension name is given to chicken setup it will simply execute the first file with the setup extension it can find Use it like any other CHICKEN extension csi q 1 gt require extension hello loading usr local lib chicken 1 hello so 2 gt hello me Hello me 3 gt Here we create a simple application irt DELLOL Sem print Hello for each lambda x printf A x command line arguments print We also need a setup script 55 hello2 setup compile hello2 scm compile hello2 install program hello2 hello2 name of the extension and files to be inst To use it just run chi cken setup in the same directory chicken setup Here we omit the extension name Now the program hello2 will be installed in the same location as the other CHICKEN tools like chicken csi etc which will normally be usr local bin Note that you need write permissions for those locations and may have to run chicken setup with administrative rights Uninstallation is just as easy chicke
225. ssible syntax for def ine macro is allowed for portability purposes only In this case the second argument must be a lambda expression or a macro name Only global macros can be defined using this form define macro NAME1 NAME2 simply copies the macro definition from NAME2 to NAME creating an alias Extended lambda list syntax optional etc can be used but note that arguments are source expressions and thus default values for optional or keyword arguments should take this into consideration 14 4 4 define for syntax syntax define for syntax NAME VAR VAR EXP1 syntax define for syntax NAME VALUE Defines the toplevel variable NAME at macro expansion time This can be helpful when you want to define support procedures for use in macro transformers for example 14 5 Conditional forms 14 5 1 switch syntax switch EXP KEY EXP1 else EXPn This is similar to Case but a only a single key is allowed and b the key is evaluated 14 5 2 unless syntax unless TEST EXP1 EXP2 Equivalent to if not TEST begin EXP1 EXP2 14 4 2 define inline 37 CHICKEN User s Manual The User s Manual 14 5 3 when syntax when TEST EXP1 EXP2 Equivalent to if TEST begin EXP1 EXP2 14 6 Record structures 14 6 1 define record syntax define record NAME SLOTNAME Defines a record type Call make NAME to create an instance of the structure with one initia
226. st Gian Paolo Ciceri John Cowan Grzegorz Chrupa amp 322 a James Crippen Tollef Fog Heen Alejandro Forero Cuervo Linh Dang Brian Denheyer dgym Chris Double Jarod Eells Petter Egesund Steve Elkins Daniel B Faken WIII Farr Graham Fawcett Fizzie Kimura Fuyuki Tony Garnock Jones Martin Gasbichler Joey Gibson Stephen C Gilardi Joshua Griffith Johannes GrA dem Damian Gryski Mario Domenech Goulart Andreas Gustafsson Sven Hartrumpf Jun ichiro itojun Hagino Matthias Heiler Karl M Hegbloom William P Heinemann Bill Hoffman Bruce Hoult Hans HAl bner Markus HA 4lsmann Goetz Isenmann Paulo Jabardo David Janssens Christian J aeger Dale Jordan Valentin Kamyshenko Daishi Kato Peter Keller Brad Kind Ron Kneusel Matthias Koeppe Krysztof Kowa amp 322 czyk Todd R Kueny Sr Goran Krampe Micky Latowicki John Lenz Kirill Lisovsky Kon Lovett Dennis Marti Charles Martin Bob McIsaac Alain Mellan Eric Merrit Perry Metzger Scott G Miller Mikael Bruce Mitchener Chris Moline Eric E Moore Julian Morrison Dan Muresan Lars Nilsson Ian Oversby o t Gene Pavlovsky Levi Pearson Nicolas Pelletier Carlos Pita Robin Lee Powell Pupeno Davide Puricelli Doug Quale Eric Raible Joel Reymont Andreas Rottman David Rush Lars Rustemeier Daniel Sadilek Oskar Schirmer Burton Samograd Reed Sheridan Ronald SchrAJder Spencer Schumann Alex Shinn Shmul Tony Sidaway Jeffrey B Siegal Andrey Sidorenko Michele Simiona
227. t 18 7 1 condition case syntax condition case EXPRESSION CLAUSE 18 6 1 get keyword 66 CHICKEN User s Manual The User s Manual Evaluates EXPRESSION and handles any exceptions that are covered by CLAUSE where CLAUSE should be of the following form CLAUSE VARIABLE KIND BODY If provided VARIABLE will be bound to the signalled exception object BODY is executed when the exception is a property or composite condition with the kinds given KIND unevaluated If no clause applies the exception is re signalled in the same dynamic context as the condition case form define check thunk condition case thunk exn file print file error exn print other error var print something else check lambda open input file gt file error check lambda some unbound variable othererror check lambda signal 99 gt something else condition case some unbound variable exn file print ignored signals error 18 7 2 breakpoint procedure breakpoint NAME Programmatically triggers a breakpoint similar to the Dr top level csi command All error conditions signalled by the system are of kind exn The following composite conditions are additionally defined exn arity Signalled when a procedure is called with the wrong number of arguments exn type Signalled on type mismatch errors for example when an argume
228. t or binary 28 2 8 pipe buf This variable contains the maximal number of bytes that can be written atomically into a pipe or FIFO 28 2 9 with input from pipe 28 2 10 with output to pipe procedure with input from pipe CMDLINE THUNK MODE procedure with output to pipe CMDLINE THUNK MODE Temporarily set the value of current input port current output port to a port for a pipe 28 2 4 close output pipe 117 CHICKEN User s Manual The User s Manual connected to the subprocess named in CMDLINE and call the procedure THUNK with no arguments After THUNK returns normally the pipe is closed and the standard input output port is restored to its previous value and any result values are returned with output to pipe gs dNOPAUSE sDEVICE jpeg dBATCH sOutputFile signballs jpg g600x600 q lambda print Z EOF TOPSC 1993 Creator HAYAKAWA Takashi XxxxxXxX XX XXXXXX XX XX C neg d mul R rlineto E exp H cvx def repeat def T dup g gt r roll J ifelse 8 H A copy z v4QX amp 93r9AxYQOZomQalxS2w O amp vMYa43d6r93rMYvx2dca D amp cjSnjSnj j 30 v amp 6A X amp 55SAxM1CD7Aj YxTTd62rmxCnTdSSTOg amp 12wECST amp JOg amp D1 amp xMO JOg L amp 544dC2Ac96ra m amp 3A F amp amp vGoGSnCTOg amp wDmlvGoS8wpn6wpS2wTCpS1Sd70v7UKk704Qkdw amp Mv Lx1S70ZES3w J J Q amp 7185d Z amp lx1CS9d9nE4 k amp X amp MY7 amp 1 J x amp jdnjdS30odS N amp mmx1C2wEC G amp 150Nx4 n amp 20 j amp 43r U amp 0777d amp
229. t eXpOEts c0 O RR 49 16 13 emit external prototypes first 2 eee ceececeeeeeseeeeeeseceeaeeeeaeeceseecaeeeeaaeceeaeceeaeeceaeesaeeeeaueceaeeceeeeeeses 50 16 14 disable interrupts ete ere ttt Hr te Rege Ee case RS CARNE Re ee ee PRE HU Eee en 50 e E EE EN 50 LO A GAM POL GEN 50 ei EE 50 16 1 8 tal E EE 51 Uer E EE vasedenaasedensnedervesedestaseseddenand NEEE REEERE SEEE EDENES 51 ee BEE EE Ee deniers teeahaeadude centile deunsteaddeaduageeadccsdecvecaseevnennens 51 16 21 l mbda lidt inset ia as 51 lee TEE 51 ee EE 51 16 24 no bound checkKs occccccconcnccococococonononononononinononancncncnnananananano no nono nono tese nono narco no nono nononacocananonanos 52 et Oe E RAR 52 16 26 post DrOGC SS iii A dens conse EVER R EE e E FA PETER ia 52 ener 52 1628 fixn m ee TEE 52 16 29 T rn time mactOs uso itasse e Pa c E RV RUE en Rar ette ri rede RE PUTA tage sacesss 52 ef REEL Ee Ae EC 52 16 3 Pextemnded binging A A AAA AA A i TAS 53 16 32 s al integrati e 53 TC 53 T634 BEES IET TNT 53 16 35 EEN 53 K Te 55 CARITA niniin iiaii i oai iE EE ER AR a Ra aia aain 55 RS E EE 55 17 Beete ee tere 55 17 4 command line arguments sss esee nennen nennen tes en nent ennnt ensi nri inen en nene nns 55 17 5 c rrent read table EE 56 MASA TT 56 17 7 eval handler ee re tanec a rr erret ovv loe TO rasura EE E e 56 17 8 force tinaliZers iia 56 17 9 1mplicit exat handl r
230. t should contain a list of alternative include pathnames separated by The environment variable CHICKEN HOME is also considered as a search path k keyword style STYLE Enables alternative keyword syntax where STYLE may be either prefix as in Common Lisp or suffix as in DSSSL Any other value is ignored n no init Do not load initialization file If this option is not given and the file cSirc or HOME csirc exists then it is loaded before the read eval print loop commences W no warnings Disables any warnings that might be issued by the reader or evaluated code q quiet Do not print a startup message s script PATHNAME This is equivalent to batch quiet no init PATHNAME Arguments following PATHNAME are available by using Command Line arguments and are not processed as interpreter options Extra options in the environment variable CST OPTIONS are ignored ss PATHNAME The same as S PATHNAME but invokes the procedure main with the value of command line arguments as its single argument If the main procedure returns an integer 9 Using the interpreter 17 CHICKEN User s Manual The User s Manual result then the interpreter is terminated returning the integer as the status code back to the invoking process Any other result terminates the interpreter with a zero exit status R require extension NAME Equivalent to evaluating require extension NAME v version Write the banner with version information to st
231. t string procedure open output string Returns a port for accumulating output in a string 18 3 Files 64 CHICKEN User s Manual The User s Manual 18 5 Feature identifiers CHICKEN maintains a global list of features naming functionality available int the current system Additionally the cond expand form accesses this feature list to infer what features are provided Predefined features are chicken and the SRFIs Scheme Request For Implementation provided by the base system Srfi 23 srfi 30 srfi 39 If the eval unit is used the default the features sr fi 0 srfi 2 srfi 6 srfi 8 srfi 9 and srfi 10 are defined When compiling code during compile time the feature compiling is registered When evaluating code in the interpreter csi the feature CSi is registered 18 5 1 features procedure features Returns a list of all registered features that will be accepted as valid feature identifiers by cond expand 18 5 2 feature procedure feature ID Returns t if all features with the given feature identifiers ID are registered 18 5 3 register feature procedure register feature FEATURE Register one or more features that will be accepted as valid feature identifiers by cond expand FEATURE may be a keyword string or symbol 18 5 4 unregister feature procedure unregister feature FEATURE Unregisters the specified feature identifiers FEATURE may be a keyword string or sy
232. t the positions FROM up to but not including TO SRFI 17 Setters for XXXvector ref are defined 22 17 byte vector gt f64vector 105 CHICKEN User s Manual The User s Manual 22 26 read u8vector procedure read u8vector LENGTH PORT Reads LENGTH bytes from the PORT and returns a fresh u8vector or less of end of file is encountered PORT defaults to the value of current input port If LENGTH is f the vector will be filled completely until end of file is reached 22 27 read u8vector procedure read u8vector LENGTH U8VECTOR PORT START Reads LENGTH bytes from the PORT writing the read input into U8VECTOR beginning at START or 0 if not given PORT defaults to the value of current input port If LENGTH is f the vector will be filled completely until end of file is reached This procedure returns the number of bytes read 22 28 write u8vector procedure write u8vector U8VECTOR PORT START END Writes the bytes U8VECTOR between the indices START inclusive and END exclusive to PORT PORT defaults to the value of Current output port Previous Unit srfi 1 Next Unit srfi 13 22 26 read u8vector 106 23 Unit srfi 13 String library see the documentation for SRFI 13 On systems that support dynamic loading the s rfi 13 unit can be made available in the interpreter CSi by entering require extension srfi 13 Previous Unit srfi 4 Next Unit srfi 14 23 Unit srfi 13 107 24 Un
233. ted in the nursery only immediate values or pointers to heap data are valid Any assignment of potential nursery data into a root array should be done via C mutate The variables have to be initialized to sensible values before the next garbage collection starts when in doubt set all locations in ptrstoC SCHEME UNDEFINED C gc protect may not called before the runtime system has been 40 39 C u 1 car 202 CHICKEN User s Manual The User s Manual initialized either by CHICKEN initialize CHICKEN run or CHICKEN invoke For a slightly simpler interface to creating and using GC roots see CHICKEN new gc root 40 45 C_gc_unprotect C function void C gc _ unprotect int n Removes the last n registered variables from the set of root variables 40 46 C post gc hook C Variable void C post gc hook int mode If not NULL the function pointed to by this variable will be called after each garbage collection with a flag indicating what kind of collection was performed either O for a minor collection or 1 for a major collection Minor collections happen very frequently so the hook function should not consume too much time The hook function may not invoke Scheme callbacks An example cat foo scm gt extern int callout int int int lt define callout foreign safe lambda int callout int int int define external callin scheme object xyz int print This is callin xyz 123 print callout 1 2 3 c
234. th position of BYTE VECTOR 32 4 8 byte vector set procedure byte vector set BYTE VECTOR INDEX N procedure set byte vector ref BYTE VECTOR INDEX N Sets the byte at the INDEXth position of BYTE VECTOR to the value of the exact integer n 32 4 9 list gt byte vector procedure list gt byte vector LIST Returns a byte vector with elements taken from LIST where the elements of LIST should be exact integers 32 4 10 make byte vector procedure make byte vector SIZE INIT Creates a new byte vector of size SIZE If INIT is given then it should be an exact integer with which every element of the byte vector is initialized 32 4 11 make static byte vector procedure make static byte vector SIZE INIT As make byte vector but allocates the byte vector in storage that is not subject to garbage collection To free the allocated memory one has to call object release explicitly Exceptions exn bounds exn runtime 32 4 6 byte vector length 165 CHICKEN User s Manual The User s Manual 32 4 12 static byte vector gt pointer procedure static byte vector gt pointer PBYTE VECTOR Returns a pointer object pointing to the data in the statically allocated byte vector PBYTE VECTOR 32 4 13 string gt byte vector procedure string gt byte vector STRING Returns a byte vector with the contents of STRING 32 5 Data in unmanaged memory 32 5 1 object evict procedure object evict X ALLOCATO
235. than to signal an error 1 fail unspecified Non matching expressions will either fail in Car or Cdr or return an unspecified value This mode applies to files compiled with the unsafe option or declaration When an error is signalled the raised exception will be of kind exn match procedure match error procedure match error procedure PROCEDURE Sets or returns the procedure called upon a match error The procedure takes one argument the value which failed to match When the error control mode is mat ch a second argument the source form of the match expression is available 15 4 Record Structures Pattern The pattern handles native record structures and SREI 9 records transparently Currently it is required that SREI 9 record predicates are named exactly like the record type name followed by a question mark character 15 5 Code Generation Pattern matching macros are compiled into 1 f expressions that decompose the value being matched with standard Scheme procedures and test the components with standard predicates Rebinding or lexically shadowing the names of any of these procedures will change the semantics of the match macros The names that should not be rebound or shadowed are null pair number string symbol boolean char procedure vector list 15 4 Record Structures Pattern 46 CHICKEN User s Manual The User s Manual equal car cdr cadr cdddr vector length vector ref reverse Length call cc
236. the same arguments The default behavior is to evaluate the argument expression and to ignore the second parameter 17 8 force finalizers If true force and execute all pending finalizers before exiting the program either explicitly by exit or implicitly when the last toplevel expression has been executed Default is Ft 17 9 implicit exit handler A procedure of no arguments When the last toplevel expression of the program has executed then the value of this parameter is called The default behaviour is to invoke all pending finalizers 17 10 keyword style Enables alternative keyword syntax where STYLE may be either prefix as in Common Lisp or Suffix as in DSSSL Any other value disables the alternative syntaxes 17 11 load verbose A boolean indicating whether loading of source files compiled code if available and compiled libraries should display a message 17 12 repl prompt A procedure that should evaluate to a string that will be printed before reading interactive input from the user in a read eval print loop Defaults to Lambda N gt 17 5 current read table 56 CHICKEN User s Manual The User s Manual 17 13 reset handler A procedure of zero arguments that is called via reset The default behavior in compiled code is to invoke the value of exit handler The default behavior in the interpreter is to abort the current computation and to restart the read eval print loop Previous Declaration
237. the expression match let x 1 y 21 z let binding values exp body binds binding to the list x y values to the list 1 2 and exp to Z in the body of the mat ch expression For the special case where pat n 1 is a pattern variable the list bound to that variable may share with the matched value pat 1 pat n pat n 1 This pattern means the same thing as the previous pattern pat 1 pat n pat n 1 k This pattern is similar to the previous pattern but the tail must be at least k elements long The pattern keywords and are equivalent pat 1 pat n pat n 1 Kl This pattern means the same thing as the previous pattern 15 2 Patterns 44 CHICKEN User s Manual The User s Manual pat 1 pat n matches a vector of length n whose elements match pat 1 through pat n pat 1 pat n pat n 1 matches a vector of length n or more where each element beyond n matches pat n 1 Z pat 1 pat n pat n 1 k matches a vector of length n k or more where each element beyond n matches pat n 1 struct pat 1 pat n matches a structure declared with def ine record or define record type field pat is intended for selecting a field from a structure field may be any expression it is applied to the value being matched and the result of this application is matched against pat and pat 1 pat n matches if all of the subpatterns match At least one subpattern
238. thing happens Invoke CSi with the C runtime option Under Windows the interpreter thinks it is not running under control of a terminal and doesn t print the prompt and does not flush the output stream properly 46 5 load compiled code dynamically in a Windows GUI application and it crashes Code compiled into a DLL to be loaded dynamically must be linked with the same runtime system as the loading application That means that all dynamically loaded entities including extensions built and installed with chicken setup must be compiled with the windows CSC option 46 6 On Windows csc exe seems to be doing something wrong The Windows development tools include a C compiler with the same name Either invoke CSC exe with a full pathname or put the directory where you installed CHICKEN in front of the MS development tool path in the PATH environment variable 46 Platform specific 225 CHICKEN User s Manual The User s Manual 46 6 On Windows csc exe seems to be doing somethingwrong 226 47 Customization 47 1 How do run custom startup code before the runtime system is invoked When you invoke the C compiler for your translated Scheme source program add the C compiler option DC EMBEDDED or pass embedded to the CSC driver program so no entry point function will be generated main When your are finished with your startup processing invoke CHICKEN main argc argv C toplevel where C toplevel is th
239. to Volker Stolz Dorai Sitaram Robert Skeels Jason Songhurst Clifford Stein Sunnan Zbigniew Szadkowski Mike Thomas Minh Thu Christian Tismer Andre van Tonder John Tobey Henrik Tramberend Vladimir Tsichevsky Neil van Dyke Sander Vesik Panagiotis Vossos Shawn Wagner Peter Wang Ed Watkeys Thomas Weidner Goeran Weinholt Matthew Welland Joerg Wittenberger Peter Wright Mark Wutka Richard Zidlicky and Houman Zolfaghari for bug fixes tips and suggestions CHICKEN uses the PCRE regular expression package http www pcre org which is written by Philip Hazel Special thanks to Brandon van Every for contributing the CMake support and for helping with Windows build issues Also special thanks to Benedikt Rosenau for his constant encouragement CHICKEN contains code from several people Eli Barzilay some performance tweaks used in TinyCLOS Mikael Djurfeldt topological sort used by compiler Marc Feeley pretty printer Aubrey Jaffer implementation of dynamic wind Richard O Keefe sorting routines Olin Shivers implementation of Let optionals and reference implementations of SRFI 1 SRFI 13 and SRFI 14 Andrew Wilcox queues Andrew Wright pattern matcher 54 Acknowledgements 237 CHICKEN User s Manual The User s Manual Previous FAQ Next Bibliography 54 Acknowledgements 238 55 Bibliography Henry Baker CONS Should Not CONS Its Arguments Part II Cheney on the M T A http home pipeline com hb
240. tor pair procedure boolean number complex rational real exact inexact list eof object string ref string set vector ref vector set char char char char lt char char numeric char alphabetic char whitespace char upper case char lower case char upcae char downcase list tail assv memv memq assoc member set car set cdr abs exp sin cos tan log asin acos atan sqrt zero positive negative vector length string length char gt integer integer gt char inexact gt exact gt lt gt lt for each map substring string append gcd lcm list exact gt inexact string gt number number gt string 50 Optimizations 232 CHICKEN User s Manual The User s Manual even odd remainder floor ceiling truncate round cons vector string string string ci make vector call with current continuation The following extended bindings are handled specially bitwise and bitwise ior bitwise xor bitwise not bit set add1 sub1 fx fx fx fx fxmod fx fx gt fx gt fixnum fxneg fxmax fxmin fxand fxior fxxor fxnot fxshl fxshr flonum fp fp fp fp atom fp fp gt fp gt fpneg fpmax fpmin arithmetic shift signum flush output thread specific thread specific set not pair null list print print u8vector gt bytevector s8vector gt bytevector ul6vector gt bytevector sl6vector gt bytevector u32vector gt bytevector s32vector gt bytevector f32vector gt bytevector f64vector gt bytevector block ref byte vector length u8vector Length
241. ty string read string reads destructively into the given STRING argument but never more characters that would fit into STRING If START is given then the read characters are stored starting at that position read st ring returns the actual number of characters read 20 8 12 read token procedure read token PREDICATE PORT Reads characters from PORT which defaults to the value of current input port and calls the procedure PREDICATE with each character until PREDICATE returns false Returns a string with the accumulated characters 20 8 13 with error output to port procedure with error output to port PORT THUNK Call procedure THUNK with the current error output port temporarily bound to PORT 20 8 14 with input from port procedure with input from port PORT THUNK Call procedure THUNK with the current input port temporarily bound to PORT 20 8 15 with output to port procedure with output to port PORT THUNK Call procedure THUNK with the current output port temporarily bound to PORT 20 9 Strings 20 9 1 conc procedure conc X Returns a string with the string represenation of all arguments concatenated together CONC could be implemented as define conc args apply string append map gt string args 20 8 11 write string 96 CHICKEN User s Manual The User s Manual 20 9 2 gt string procedure gt string X Returns a string representation of X 20 9 3 string chop
242. tyle lambda lists are supported DSSSL formal argument lists are defined by the following grammar lt formal argument list gt gt lt required formal argument gt optional lt optional formal argument gt rest lt rest formal argument gt key lt key formal argument gt lt required formal argument gt gt lt ident gt lt optional formal argument gt gt lt ident gt lt ident gt lt initializer gt lt rest formal argument gt gt lt ident gt lt key formal argument gt gt lt ident gt lt ident gt lt initializer gt lt initializer gt gt lt expr gt When a procedure is applied to a list of actual arguments the formal and actual arguments are processed from left to right as follows e Variables in required formal arguments are bound to successive actual arguments starting with the first actual argument It shall be an error if there are fewer actual arguments than required formal arguments e Next variables in optional formal arguments are bound to any remaining actual arguments If there are fewer remaining actual arguments than optional formal arguments then variables are bound to the result of the evaluation of initializer if one was specified or otherwise to f The initializer is evaluated in an environment in which all previous formal arguments have been bound e If there is a rest formal argument then it is bound to a list of all remaining actual arguments The rema
243. ument is a port then the port will not be closed The READER argument specifies the procedure used to read expressions from the given file or port and defaults to read The reader procedure will be called with a single argument an input port If MAXCOUNT is given then only up to MAXCOUNT expressions will be read in 20 8 6 read line 20 8 7 write line procedure read line PORT LIMIT procedure write line STRING PORT Line input and output PORT defaults to the value of current input port and current output port respectively if the optional argument LIMIT is given and not f then read line reads at most LIMIT characters per line 20 8 8 read lines procedure read lines PORT MAX Read MAX or fewer lines from PORT PORT defaults to the value of current input port PORT may optionally be a string naming a file 20 8 9 read string 20 8 10 read string 20 8 11 write string procedure read string NUM PORT procedure read string NUM STRING PORT START procedure write string STRING NUM PORT Read or write NUM characters from to PORT which defaults to the value of current input port or current output port respectively If NUM is f or not given then all data up to the end of file is read or in the case of write string the whole string is written If no more input is available 20 8 5 read file 95 CHICKEN User s Manual The User s Manual read string returns the emp
244. und toplevel variables is allowed set PROCEDURE is supported as CHICKEN implements SRFI 17 4 2 1 The cond form supports SRFI 61 4 2 2 It is allowed for initialization values of bindings in a Let rec construct to refer to previous variables in the same set of bindings so letrec foo 123 bar foo bar is allowed and returns 123 4 2 3 begin is allowed in non toplevel contexts and evaluates to an unspecified value 4 2 5 Delayed expressions may return multiple values 5 2 2 CHICKEN extends standard semantics by allowing internal definitions everywhere and not only at the beginning of a body A set of internal definitions is equivalent to a Let rec form enclosing all following expressions in the body let foo 123 bar define foo 456 baz foo expands into let foo 123 bar letrec foo 456 baz foo 5 2 define with a single argument is allowed and initializes the toplevel or local binding to an unspecified value CHICKEN supports curried definitions where the the variable name may also be a list specifying a name and a nested lambda list So define make adder x y x y is equivalent to define make adder x lambda y x y 6 CHICKEN provides numerous non standard procedures See the manual sections on library units for more information 6 2 4 The special IEEE floating point numbers nan inf and inf are supported as is negative zero 6 3 4 User
245. untime library has been linked with this version of the Chicken libraries Possible return values are static dynamic or unknown On systems not compiled with the Microsoft C compiler C runtime always returns unknown 18 8 13 system procedure system STRING Execute shell command The functionality offered by this procedure depends on the capabilities of the host shell 18 9 Execution time 18 9 1 cpu time procedure cpu time Returns the used CPU time of the current process in milliseconds as two values the time spent in user code and the time spent in system code On platforms where user and system time can not be differentiated system time will be always be 0 18 9 2 current milliseconds procedure current milliseconds Returns the number of milliseconds since process or machine startup 18 9 3 current seconds procedure current seconds 18 8 11 software version 71 CHICKEN User s Manual The User s Manual Returns the number of seconds since midnight Jan 1 1970 18 9 4 current gc milliseconds procedure current gc milliseconds Returns the number of milliseconds spent in major garbage collections since the last call of current gc milliseconds and returns an exact integer 18 10 Interrupts and error handling 18 10 1 enable warnings procedure enable warnings BOOL Enables or disables warnings depending on wether BOOL is true or false If called with no arguments this procedure r
246. upport so 2 gt define foo glass lambda x y x y 3 gt glass lambda set foo y 99 4 gt foo 33 132 41 6 chicken setup reference Available options h help Show usage information and exit V version Display version and exit R repository PATHNAME When used without an argument the path of the extension repository is displayed on standard output When given an argument the repository pathname and the repository path parameter will be set to PATHNAME for all subsequent operations The default repository path is the installation library directory usually usr local lib chicken or if set the directory given in the environment variable CHICKEN_REPOSITORY PATHNAME should be an absolute pathname P program path PATHNAME When used without an argument the path for executables is displayed on standard output When given an argument the program path for installing executables and scripts will be set to PATHNAME for all subsequent operations PATHNAME should be an absolute pathname h host HOSTNAME PORT Specifies alternative host for downloading extensions optionally with a TCP port number which defaults to 80 u uninstall EXTENSION Removes all files that were installed for EXTENSION from the file system together with any metadata that has been stored l list NAME List all installed extensions or show extension information r run FILENAME Load and execute given file S script
247. urce file is compiled with the CSC compiler driver 16 23 no argc checks declaration specifier no argc checks Disables argument count checking 16 18 inline limit 51 CHICKEN User s Manual The User s Manual 16 24 no bound checks declaration specifier no bound checks Disables the bound checking of toplevel bindings 16 25 no procedure checks declaration specifier no procedure checks Disables checking of values in operator position for being of procedure type 16 26 post process declaration specifier post process STRING Arranges for the shell commands STRING to be invoked after the current file has been translated to C Any occurrences of the substring in the strings given for this declaration will be replaced by the pathname of the currently compiled file without the file extension This declaration will only work if the source file is compiled with the CSC compiler driver 16 27 number type 16 28 fixnum arithmetic declaration specifier number type TYPE declaration specifier fixnum arithmetic Declares that only numbers of the given type are used TYPE may be fixnum or generic which is the default 16 29 run time macros declaration specifier run time macros Equivalent to the compiler option of the same name macros defined in the compiled code are also made available at runtime 16 30 standard bindings declaration specifier standard bindings SYMBOL
248. ut an identifier list inlining of known procedures is enabled this is equivalent to the inline compiler option When an identifier list is given then inlining is enabled only for the specified global procedures The negated forms not inline and not inline IDENTIFIER disable global inlining or inlining for the given global procedures only respectively 16 13 emit external prototypes first 50 CHICKEN User s Manual The User s Manual 16 18 inline limit declaration specifier inline limit THRESHOLD Sets the maximum size of procedures which may potentially be inlined The default threshold is 10 16 19 interrupts enabled declaration specifier interrupts enabled Enable timer interrupts checks in the compiled program the default 16 20 keep shadowed macros declaration specifier keep shadowed macros Normally when a toplevel variable is assigned or defined that has the same name as a macro the macro definition will be removed in addition to showing a warning This declaration will disable the removal of the macro 16 21 lambda lift declaration specifier lambda lift Enables lambda lifting equivalent to the Lambda Lift option 16 22 link options declaration specifier link options STRING Declares additional linker compiler options that are to be passed to the subsequent compilation pass that links the generated code into an executable or library This declaration will only work if the so
249. working directory If the optional argument DIR is given then current directory DIR is equivalent to change directory DIR 28 1 3 create directory procedure create directory NAME Creates a directory with the pathname NAME 28 1 4 delete directory procedure delete directory NAME Deletes the directory with the pathname NAME The directory has to be empty 28 1 5 directory procedure directory PATHNAME SHOW DOTFILES Returns a list with all files that are contained in the directory with the name PATHNAME which defaults to the value of current directory If SHOW DOTFILES is given and not f then files beginning with 28 Unit posix 115 CHICKEN User s Manual The User s Manual are not included in the directory listing 28 1 6 directory procedure directory NAME Returns t if there exists a file with the name NAME and if that file is a directory or f otherwise 28 1 7 glob procedure glob PATTERN1 Returns a list of the pathnames of all existing files matching PATTERN1 which should be strings containing the usual file patterns with matching zero or more characters and matching zero or one character 28 1 8 set root directory procedure set root directory STRING Sets the root directory for the current process to the path given in STRING using the chroot function If the current process has no root permissions the operation will fail 28 2 Pipes 28 2 1 call
250. ws GUI application and it crasbes 225 46 6 On Windows csc exe seems to be doing something wrong 225 FC ESCO MEA EO EE 227 47 1 How do I run custom startup code before the runtime system is invoked 227 47 2 How can I add compiled user Passes O enooonnccconocicioccconocononcconnnnono conan nc nnno cc nnn con nnnnnnc nano enne nene 227 A8 Macia in 228 48 1 Why doesn t my fancy macro work in compiled code 228 48 2 Why are macros not visible outside of the compilation unit in which they are defined 228 AO VV at GS and CELDA rs 229 49 1 Why does my program crash when I use callback functions from Scheme to C and back to SCHEME ASAIN e H 229 49 2 Why does the linker complain about a missing function C toplevel 12 229 49 3 Why does the linker complain about a missing function C toplevel 2 229 49 4 Why does my program crash when I compile a file with unsafe or unsafe EE ra EE 229 49 5 Why do I get a warning when I define a global variable named match 229 49 6 Why don t toplevel continuations captured in interpreted code work 230 49 7 Why does define reader ctor not work in my compiled program 230 49 8 Why do built in units such as srfi 1 srfi 18 and posix fail to load 231 49 9 How ca
251. xecutable programs or scripts Additionally the list of installed files and user defined metadata is stored in the repository If no extension name is given on the command line and if none of the options List version repository without argument program path without argument fetch fetch tree or docindex is given then all setup scripts in the current directory are processed 41 3 Creating extensions Extensions can be created by creating an optionally gzipped tar archive named EXTENSION egg containing all needed files plus a Setup script in the root directory After chicken setup has extracted the files the setup script will be invoked There are no additional constraints on the structure of the archive but the setup script has to be in the root path of the archive 4 chicken setup 205 CHICKEN User s Manual The User s Manual 41 4 Procedures and macros available in setup scripts 41 4 1 install extension install extension ID FILELIST INFOLIST Installs the extension library with the name ID All files given in the list of strings FILELIST will be copied to the extension repository It should be noted here that the extension id has to be identical to the name of the file implementing the extension The extension may load or include other files or may load other extensions at runtime specified by the require at runtime property FILELIST may be a filename a list of filenames or a list of pairs of th
252. xpression an equal s expression pat 1 pat n a proper list of n elements pat 1 pat n pat n 1 15 Pattern Matching 42 CHICKEN User s Manual The User s Manual a list of n or more elements pat 1 pat n pat n 1 k a proper list of n k or more elements 1 pat 1 pat n a vector of n elements pat 1 pat n pat n 1 k a vector of n k or more elements struct pat 1 pat n a structure field pat a field of a structure and pat 1 pat n if all of pat 1 through pat n match or pat 1 pat n if any of pat 1 through pat n match not pat 1 pat n if none of pat 1 through pat n match predicate pat 1 pat n if predicate true and pat 1 through pat n all matc set identifier anything and binds identifier as a setter get identifier anything and binds identifier as a getter gp a quasipattern qp itself the empty list Ft itself f itself string an equal string number an equal number character an equal character symbol an equal symbol qp 1 qp n a proper list of n elements qp 1 qp n qp n 1 a list of n or more elements qp 1 qp n qp n 1 k a proper list of n k or more elements qp 1 qp n a vector of n elements qp 1 qp n qp n 1 k a vector of n k or more elements pat a pattern pat a pattern spliced The notation k denotes a keyword consisting of three consecutive
253. xtension 151 CHICKEN User s Manual The User s Manual 29 5 1 for each line procedure for each line PROCEDURE PORT Calls PROCEDURE for each line read from PORT which defaults to the value of current input port The argument passed to PORCEDURE is a string with the contents of the line excluding any line terminators When all input has been read from the port for each line returns some unspecified value 29 5 2 for each argv line procedure for each argv line PROCEDURE Opens each file listed on the command line in order passing one line at a time into PROCEDURE The filename is interpreted as current input port If no arguments are given on the command line it again uses the value of current input port During execution of PROCEDURE the current input port will be correctly bound to the current input source This code will act as a simple Unix cat 1 command for each argv line print 29 5 3 port for each procedure port for each FN THUNK Apply FN to successive results of calling the zero argument procedure THUNK until it returns eof discarding the results 29 5 4 port map procedure port map FN THUNK Apply FN to successive results of calling the zero argument procedure THUNK until it returns eof returning a list of the collected results 29 6 Executing shell commands with formatstring and error checking 29 6 1 system procedure system FORMATSTRING ARGUMENT1 29 5 1 fo
254. ze NUMBER Sets the size that the heap of the compiled application should have at startup time heap growth PERCENTAGE Sets the heap growth rate for the compiled program at compile time see hg heap shrinkage PERCENTAGE Sets the heap shrinkage rate for the compiled program at compile time see hs help Print a summary of available options and the format of the command line parameters and exit the compiler import FILENAME Read exports from linked or loaded libraries from given file See also check imports This is equivalent to declaring declare import FILENAME Implies check imports include path PATHNAME Specifies an additional search path for files included via the include special form This option may be given multiple times If the environment variable CHICKEN INCLUDE PATH is set it should contain a list of alternative include pathnames separated by The environment variable CHICKEN HOME is also considered as a search path inline Enable procedure inlining for known procedures of a size below the threshold which can be set through the inline limit option inline limit THRESHOLD Sets the maximum size of a potentially inlinable procedure This option is only effective when inlining has been enabled with the inline option The default threshold is 10 keyword style STYLE Enables alternative keyword syntax where STYLE may be either prefix as in Common Lisp suffix as in DSSSL or none Any other value

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