Section - Eli - University of Colorado Boulder
Contents
1. cmd sets specs exe input run testdir cmd myprog u input sets specs exe stdout run Every request for run re executes the command regardless of whether anything on which the execution depends has changed No other products can be derived from run In partic ular it is not possible to obtain warning messages or error reports by appending warning or error see Section 3 1 warning page 11 to this derivation If a warning message or error report is generated Eli will specify the derivation step for which warning or abort status was set The target of the derivation should be changed to this step followed by warning or error and the modified request submitted to Eli 4 5 Debugging Debug a Program Interactively at the Source Level dbx core file dbx gdb core file gdb dbx starts an interactive session with the source level debugger of the machine on which Eli is running This session allows controlled execution of the generated processor Execu tion takes place in the current working directory and all of the source files of the generated compiler are made available dbx must be used with the debug parameter see Section 4 9 debug page 15 Alternatively gdb can be used to use the GNU debugger gdb instead of dbx Both dbx and gdb check the environment variable ELI_DEBUGGER If ELI_DEBUGGER is set then its value is taken as the name of the debugger to be used The debugger whose name is the value of2. A list of the objects on which the given object directly depends The number used to name the file in the cache and the Eli derivation is given for each object 6 2 outputs Objects Depending on a Given Object outputs A list of the objects that directly depend on the given object The number used to name the file in the cache and the Eli derivation is given for each object 6 3 test Check Whether an Object has been Modified test The given object is checked to see whether its last modification time agrees with the value held by Eli This product is used when you have modified an object by some external means and wish to inform Eli of that modification For example suppose that Eli complains that a particular object needed to satisfy the current request is unavailable You supply the object say its name is pascal lido by copying it from some other directory The following request will inform Eli of your action pascal lido test 6 4 redo Ask Eli to Carry Out a Derivation redo Tells Eli that a particular step in a derivation should be recomputed when it is next requested even if the that step has already been computed and inputs to that step have not changed This utility is useful when a transient error in a derivation step occurs but the tool that implements the derivation step did not recognize it as a transient error 20 Products and Parameters Reference sets specs level_6_specs redo The next time a
3. Example foo specs 0rdl Explnfo gt For a more detailed description of Liga s protocol options and more advanced options see Section Liga Control Language Manual in Liga Control Language Manual 2 8 OrdInfo Information about attribute dependence OrdInfo Obtain information about the processing of LIDO specifications especially information concerning the attribute dependences The protocol provides for each grammar rule the set of direct dependences between attributes occurring in this rule Additional information about remote attribute access and attribute storage optimization can be obtained by adding the parameters ExpI and 0ptimI Example foo specs tExpl OrdInfo gt For a more detailed description of Liga s protocol options and more advanced options see Section Liga Control Language Manual in Liga Control Language Manual 10 Products and Parameters Reference 2 9 OptimInfo Information about attribute storage optimization OptimInfo Obtain information about the processing of LIDO specifications especially information on attribute storage optimization For each attribute this protocol provides information where this attribute is stored Possible storage locations are tree node global variable and global stack Additional information about remote attribute access and attribute dependences can be obtained by adding the parameters ExpI and 0rdl Example foo specs Expl Optiminfo gt For a more d
4. doc html Note that fwHtml can not be applied to a type specs file The documentation text of the type fw file must contain the following FunnelWeb type setter pragma Cp typesetter html Chapter 6 Obtaining Information About the Derivation 19 6 Obtaining Information About the Derivation Eli derives the requested product via a sequence of steps Like any expert system it is capable of providing information about those steps Since one of the major goals of Eli is to hide the steps required to derive a particular product thus reducing the cognitive load on the user it does not automatically provide this information By setting the LogLevel variable a user can control the amount of feedback that Eli provides about the derivation as it is being carried out see Section Hints on Session Management in Guide for New Eli Users This feedback only provides information about what is happening not why Sometimes it is important to discover things like the names of intermediate products what objects a given object depends upon and what objects a given object influences That information must be accessed via specific requests Eli does not bring an object up to date before applying any of the derivations discussed in this chapter If you wish to execute one of these derivations on an up to date object you must first bring that object up to date with an explicit request 6 1 inputs Objects on which a Given Object Depends inputs
5. moddir expr 0 MI gt 1 e s NAME 2 g s KEY 3 g moddir AlgScope fw gt 2 AlgScope fw It first sets noddir to the name of the directory in which it resides then uses sed to modify file AlgScope fw in that directory The script replaces the string NAME with the string specified by the instance parameter of the original request If no instance parameter was supplied 1 is empty and every occurrence of the string NAME is simply deleted Similarly it either replaces the string KEY with the string specified by the referto parameter or deletes it Finally the name of the output file depends on the instance parameter of the original request The output file will become part of the specification that contained the inst request 2 7 ExpInfo Information about remote attribute access ExpInfo Obtain information about the processing of LIDO specifications especially informa tion concerning the expansion of remote attribute accesses i e INCLUDING CON STITUENTS and CHAIN The generated listing describes how each remote access con struct can be replaced by a set of equivalent computations propagating the accessed values through adjacent contexts This file is useful if special difficult cases regarding problems with remote dependences arise Additional information about attribute dependences and attribute storage optimization can be obtained by adding the parameters OrdI and 0ptimI
6. Diagnosing Specification Inconsistencies 11 3 Diagnosing Specification Inconsistencies Inconsistencies in the specification are detected by Eli in much the same way as a compiler detects inconsistencies in a normal program Depending upon the nature of the inconsis tency Eli will set the status of the requested processor to either warning or abort In either case the user is informed of the status of the requested product If the status is abort the product will not be delivered To obtain further information about the in consistencies a request should be made to derive one of the diagnostic products discussed in this section from the product whose status was reported as warning or abort For example suppose that the following request see Section 1 1 exe page 3 led to an abort status pascal specs exe Further information could then be obtained by making the request pascal specs exe help Note that the original request is repeated exactly with help being simply added to the end See Section Referring to Objects in Eli User Interface Reference Manual for more information about the form of a request 3 1 warning Warning Messages and Error Reports warning A listing of all error reports and warning messages delivered by any step in a deriva tion For example the following request might be used during development of a set of specifications for a Pascal compiler pascal specs exe war
7. ELI_DEBUGGER must accept the same parameters as either the Berkeley debugger dbx or the GNU debugger gdb After setting ELI_DEBUGGER use either dbx or gdb to activate your program depending upon which set of parameters is appropriate An existing core file can be supplied by specifying the core parameter Every request for dbx or gdb re executes the generated processor regardless of whether anything on which the execution depends has changed No other products can be derived from dbx or gdb In particular it is not possible to obtain warning messages or error reports by appending warning or error see Section 3 1 warning page 11 to this derivation If a warning message or error report is generated Eli will specify the derivation step for which warning or abort status was set The target of the derivation should be changed to this step followed by warning or error and the modified request submitted to Eli 4 6 Monitoring Monitor a program at the specification level mon mongdb mon starts an interactive session with the Noosa monitoring system see Section in Monitoring Reference Manual This session allows execution monitoring of the generated processor at the level of the specifications used to generate it This concentration on the specification level contrasts with the use of debuggers to monitor the processor s execution in terms of its source code see Section 4 5 Debugging page 14 Chapter 4 Testing a Ge
8. main program OM ittiN8 ooooocococococccccooo 5 makefil unica ds da 3 Mi iris oe or 4 modification checking for 19 MON 2 ern TEET EEES 14 15 MONGOD coc een 14 15 MONITOR acia ie 15 MONILOFINE cepto teh baal a rd 14 15 N name analySiS pir eere menikida 8 naming instances of generic modules 10 HONAIN Ener 5 NOOS8 ce oreet e Rr EDUC POE E RU 14 15 omitting the main program 5 omitting the parser uses 5 OptimI nto perecieron RES AR RM REG 10 OrdInfo id EIE RINT 9 outputs sse bn us id han 13 output of identifiers 0 eee 4 OUTPUTS een ent 19 P Parameter u nenne 1 parameters command line 15 parsable rana weni ses ee 12 Parser 226 ee ae 4 parser generation i e in 12 parser generator selection 5 Products and Parameters Reference parser omitting lese Fab 5 PE esca Aga uerb a E dade aded 7 POS fest As O we 5 printtokens o ong A n PEE Ree 16 product 2 nee E a ES 1 products relationships among 19 PS achte diversities dab steel ANE LOGO seen awe ions Meee ae 19 Tefo bOne iii 10 DUN di de era ea ete Hae tees 13 run with typical input data 13 S SCANNER ee des 8 scripts invocation via inst 8 ShOWEG cosy arenas ga ras aaa 10 Shoe sh 2 2cccaciaace dadas 10 SOUL CE 3 sce Ai a ee 3 source language file ooooooocoocmooo 3
9. make in dir unaltered routines will not be recompiled 1 3 fwGen Obtain the Product Files Generated by FunnelWeb fwGen 4 Products and Parameters Reference A directory containing the files generated by the FunnelWeb tangle phase See Section Output Files in FunnelWeb User s Manual This derivation can only be applied to type fw files The resulting directory will contain all files generated by 0 macros in the FunnelWeb file For example to generate the tangled files from the file pascal fw use the following Eli request pascal fw fwGen gt dir Here dir is the name of an existing directory 1 4 fold Make the Processor Case Insensitive fold Eli normally produces a compiler that treats upper and lower case letters as distinct characters in identifiers and keywords If fold is used implementation of the processor mkidn is altered so that it treats the upper and lower case versions of a letter as being identical The fold causes all identifiers to be stored in their upper case form When an identifier is output therefore it will appear in upper case regardless of its representation in the input text 1 5 define Set C Pre Processor Symbols define item All C compilations required by the derivation will be provided with flag Ditem for each item in the argument An item is any sequence of non white space characters other than apostrophes Items are separated by white space Any number of i
10. optimization AA 10 2 10 show LIDO Table Viewers showFe and showMe 10 2 11 instance Name an Instance of a Generic Module 10 2 12 referto Relate Instances of Generic Modules 10 3 Diagnosing Specification Inconsistencies 11 3 1 warning Warning Messages and Error Reports 11 3 2 error Error Reports een en 11 3 3 help Cross Reference to Documentation o oooooooooo 11 3 4 parsable Verify that the Grammar is Parsable 12 3 5 gencode Code Derived from the Specifications 12 4 Testing a Generated Processor 13 4l cmd Command Line to be Executed a eoe 13 4 2 stdout Standard Output from Processor Execution 13 4 3 output Files Resulting from Processor Execution 13 4 4 run Execute the Processor in the Current Directory 13 4 5 Debugging Debug a Program Interactively at the Source Level A ubi be a 14 4 6 Monitoring Monitor a program at the specification level 14 4 7 monitor Request monitoring support 000 15 4 8 arg Supply Command Line Parameters 000065 15 li Products and Parameters Reference 4 9 debug Request debugging information in object files 15 4 10 printtokens Request Token Printing Code 15 5 Producing Formatted Documents 17 DL Be Postocript Gey anne s
11. the Grammar is Parsable parsable Verifies that the grammar satisfies the conditions necessary to generate a parser The result of this derivation should be directed to the screen or an editor see Section Extracting and Editing Objects in Eli User Interface Reference Manual Using the help derivation is not recommended because the output is hard to read 3 5 gencode Code Derived from the Specifications gencode A directory containing the original specification files and all files generated from them This directory is useful for exploring the relationships among the generated code files when certain inconsistencies are detected Although the directory can be extracted from the cache see Section Extracting and Editing Objects in Eli User Interface Reference Manual it is usually examined by re questing the viewlist product sets specs gencode viewlist This derived object is an interactive execution of the user s preferred shell in the derived directory sets specs gencode It allows the user to employ all of the usual tools 1lint 1 ctags 1 editors and so forth to perform arbitrary analysis on the files Any file supplied as part of the specification can be altered directly and when the session ends Eli will take account of those alterations Generated files can be examined and altered copies created for testing purposes but those alterations will not be permanent At the beginning of the session the d
12. Products and Parameters Reference Revision 2 14 Compiler Tools Group Department of Electrical and Computer Engineering University of Colorado Boulder CO USA 80309 0425 Table of Contents 1 Processor Generation sess 3 1 1 exe Executable Version of the Processor 2 2222 3 1 2 source Source Version of the Processor 222222 3 1 3 fwGen Obtain the Product Files Generated by FunnelWeb 3 1 4 fold Make the Processor Case Insensitive oooooooo oo 4 1 5 define Set C Pre Processor Symbols 0oooccoocccccoooccco 4 1 6 ignore Do Not Verify include FileS oooooooooccccnnco o 4 1 7 parser Choose the parser generator ocooooccccconccccnn cs 4 1 8 nomain Omitting the main program 20000 5 2 Generating Specifications T 2 1 consyntax Concrete Syntaks secssscercrerci nesis rean eee eee T 2 2 abstree Abstract Tree Grammar 0 00 cece cece eens 7 2 3 absyntax Abstract Syntax sess eee f 2 4 pgram Parsing Grammar 0 cece eee ene 7 2 5 kwd Recognize Specified Literals as Identifiers 8 2 6 inst Instantiate a Generic Module 0c eee ee 8 2 7 Explnfo Information about remote attribute access 9 2 8 OrdInfo Information about attribute dependence 9 2 9 OptimInfo Information about attribute storage
13. ance in the grammar and no type gla file describes their structure The kwd product is used when literals are representative of the character strings that should appear in the program but not necessarily identical to them The classic case in which kwd would be used and from which its name is derived is the recognition of mixed case keywords A literal if appearing in a Pascal grammar is representative of the character strings if If iF and IF but is identical to only the first Whenever any one of these four character strings appears in a Pascal program it should be recognized by the scanner as an instance of the literal if All Pascal keywords behave in this fashion and each has the form of an identifier Suppose that file pkeys gla defines the structure of the literals used in the grammar and the following line were added to one of the type specs files for a Pascal compiler pkeys gla kwd This would prevent the scanner of the generated compiler from recognizing Pascal key words explicitly as the character sequences specified by the literals given in the grammar Other literals such as which did not fit the definition given by pkeys gla would still be recognized by the scanner as the specified character sequences It is important to remember that the type gla file to which the kwd derivation is applied defines the form of the literals in the grammar not in the input text 2 6 inst Instantiate a Generic Mod
14. ans asien 17 5 2 dvi Device independent TeX typesetter file 17 5 9 Iwlex TeX input fles vere Rer Re ERR ERR 17 5 4 TwHtiml HTML fie ebbe xt ae 17 6 Obtaining Information About the Derivation RH 19 6 4 inputs Objects on which a Given Object Depends 19 6 2 outputs Objects Depending on a Given Object 19 6 3 test Check Whether an Object has been Modified 19 6 4 redo Ask Eli to Carry Out a Derivation 19 A product is a Unix file or directory that can be requested from Eli see Section Top in Eli User Interface Reference Manual Parameters allow the requestor to control some characteristics of the requested product This document defines the available products and associated parameters It is intended as a reference manual rather than a tutorial The products and parameters are grouped by function use the index to find a particular product or parameter by name Eli s products and parameters can be divided into six groups The processor group allows a user to generate a processor and extract it from Eli in either executable or source form or to copy the complete set of files defining a processor Inconsistencies in the specifications cause Eli to set either warning or abort status for the request being made additional infor mation about these inconsistencies can be obtained via the diagnostic gr
15. dout page 13 output see Section 4 3 output page 13 dbx gdb see undefined debugging page undefined mon mongdb see undefined monitoring page undefined or run see Section 4 4 run page 13 products After testing has been completed exe can be used to extract the executable processor from the cache for use in arbitrary contexts pascal specs exe gt pc 1 2 source Source Version of the Processor Source A directory containing the source language files and header files necessary to construct the generated processor This directory is completely self contained unless a library spec ification was given by the user All Eli library routines used are included in source form There is also a makefile so an executable processor can be constructed by entering the directory and giving the command make To extract the directory from the cache use the following Eli request pascal specs source gt dir Here dir is the name of an existing directory The directory may or may not be empty If it is empty Eli will copy all of the files needed to construct the processor except user specified libraries from the cache to dir Otherwise Eli will copy only those files that differ from the files with the same name in dir This means that if you alter the specifications for the processor and then request a new source directory only the files actually affected by your specification change will be updated Therefore if you run
16. ed Documents I 5 Producing Formatted Documents Eli supports two mechanisms for producing formatted documents Texinfo and Funnel Web Both on line hypertext and printed documents can be produced from Texinfo type tn files arbitrary specification files and printed documents can be produced from FunnelWeb type fw files In this chapter we consider only the production of printed documents 5 1 ps PostScript file ips A file containing the result of formatting a type tnf file 5 2 dvi Device independent TeX typesetter file dvi A file containing the result of formatting a type tnf file This file cannot be printed directly but must be used as input to some typesetter dependent program 5 3 fwTex TeX input file fwTex A file suitable for input to TeX containing the result of weaving a type fw file doc fw fwTex gt doc tex Note that fwTex can not be applied to a type specs file If the documentation text of the type fw file contains TeX or LaTeX commands it should also contain the following FunnelWeb typesetter pragma Cp typesetter tex This pragma is not required if the documentation text contains no TeX or LaTeX commands but including it will have no effect If no typesetter pragma is given any TeX and LaTeX commands in the documentation will simply appear in the output as they stand in the input 5 4 fwHtml HTML file fwHtml An HTML containing the result of weaving a type fw file doc fw fwHtml
17. etailed description of Liga s protocol options and more advanced options see Section Liga Control Language Manual in Liga Control Language Manual 2 10 show LIDO Table Viewers showFe and showMe showFe showMe Obtain a list of files that contain internal representations of LIDO text translated into readable text showFe shows LIDO text after the processing by the frontend of the Liga System showMe shows the same information after attribute evaluator construction These informations can be useful for debugging a LIDO Specification or to understand LIGA Processing in more depth See Section Overview in SHOW Debugging Information for LIDO for more details 2 11 instance Name an Instance of a Generic Module instance string Use string to name the instance generated by the request No spaces are allowed within the string and characters meaningful to the shell that interprets the associated type gnrc file may cause problems Not all generic modules allow distinct instances to be created See the documentation of each such module for the precise effect of instance 2 12 referto Relate Instances of Generic Modules referto string Use string to relate the current instance of a generic module to some specific instance of another generic module Not all generic modules allow relationships to be specified See the documentation of each such module for the precise effect of referto Chapter 3
18. ion of specifications having a particular structure These specifications themselves can be generated given simpler spec ifications The products and parameters described in this chapter are most often used in requests that appear in type specs files They result in specifications that are then used to describe the complete processor 2 1 consyntax Concrete Syntax consyntax Requesting consyntax will result in a type con file containing the complete concrete syntax This includes all concrete syntax rules provided by the user in type con files translated into strict BNF form as well as rules added to the concrete syntax as a result of the mapping process see Section Mapping in Syntactic Analysis 2 2 abstree Abstract Tree Grammar abstree Requesting abstree will result in a type lido file containing the complete abstract tree grammar This consists of all rules supplied by the user in type lido files plus any additional rules derived from rules appearing only in type con files in the syntax mapping process see Section Mapping in Syntactic Analysis 2 3 absyntax Abstract Syntax absyntax Requesting absyntax will result in a type lido file containing the complete abstract syntax This derivation differs from the abstree derivation see Section 2 2 abstree page 7 in that rules which can only be derived for computed subtrees see Section Com puted Subtrees in LIDO Reference Manual a
19. irectory contains only symbolic links If you want to alter a file temporarily simply delete the symbolic link and replace it with the copy of the file You may also create other files in the directory as you see fit If you create subdirectories of the local directory you should delete those subdirectories before exiting the shell Plain files need not be deleted If you exit the shell and then re derive gencode any files you created may or may not be present Thus you should not expect that files you create will be retained any file you wish to keep should be written to another directory Chapter 4 Testing a Generated Processor 13 4 Testing a Generated Processor After all of the inconsistencies detected by Eli have been removed from a set of specifications the generated processor must be run with typical input data to verify that the specifications actually describe the desired behavior Since improper processor behavior is always due to a specification error the specifications must be altered whenever such behavior occurs This means that a new processor must be generated and testing continued The products and parameters described in this section allow the user to remain within the Eli system during this entire process 4 1 cmd Command Line to be Executed cmd A specification of a command line to be executed by the host machine This parameter is a list of the words of the command line Each word is specified by an odin expressi
20. nerated Processor 15 mongdb allows specification level monitoring to be mixed with source level debugging using gdb see Section 4 5 Debugging page 14 When using this mode of monitoring the source level debugger has control of the executing program and runs as a child of the monitoring system Consequently the monitoring system is inactive whenever the debugger is at its prompt level These derivations can be affected by the setting of the ELI_ DEBUGGER environment variable If this variable is set it is assumed to be a gdb compatible debugger Thus you can use other debuggers that support the same command line options For example graphical debuggers such as ddd can be used The mon and mongdb products imply the monitor parameter see Section 4 7 monitor page 15 which causes the system to produce a processor that includes the monitoring code The arg parameter see Section 4 8 arg page 15 can be used to specify command line arguments to the program being monitored The following two derivations have the same effect sets specs monitor arg input mon sets specs arg input mon 4 7 monitor Request monitoring support monitor If the monitor parameter is used Eli includes monitoring support in the generated processor Processors containing monitoring support can be monitored at the specification level using the Noosa monitoring environment see Section in Execution Monitoring Reference via the mon or mongdb
21. ning The product being requested here is the reports of anomalies encountered during the derivation pascal specs exe These reports indicate inconsistencies in the specifications listed in the file pascal specs 3 2 error Error Reports error A listing of all error reports delivered by any step in a derivation During development it is preferable to use the help product see Section 3 3 help page 11 because it provides more information than error If a particular derivation produces a number of uninteresting warnings however error is useful 3 3 help Cross Reference to Documentation help Starts an interactive session with the hypertext reader see Section System Documen tation in Guide for New Eli Users This session is an explanation of reports delivered during a derivation The session provides a menu of files containing the reports and for each file a menu of hypertext document nodes pertaining to the errors in that file Any file supplied as part of the specification can be altered using the edit command of the hypertext reader and when the session ends Eli will take account of those alterations 12 Products and Parameters Reference Generated files can be examined with the edit command and altered copies created for testing purposes but those alterations will not be permanent There is no use in requesting the help product unless a derivation has errors or warnings 3 4 parsable Verify that
22. ny derivation requires the object sets specs level_6_specs it will be recomputed Index Index SE Flag ria ted der ii 15 1 unavailable error report 19 Eloo ep prie e p E ARRIUS 11 abstfeQ ie so d e cd ee T absyntaBX c lese bk gc eb taeda HERES Rees i altering files ber rales lie 11 Mai ERROR EU BESTER Er 15 basic Symbol ovio 16 BOTTOMUD 242 20240020 RR as T C C Compilations He ea 4 cage insensitivity 1 000 41 03 O ERENER 4 character strings 4209 Ri ern 8 EMd 222 Bee eher 13 C LA ia e ieh 5 command line parameters sss 15 constructing generic modules 8 COnSyHDtax i l016 len eb PRX SPP REGERE REDE EE if controlled execution 000 14 ol C rm 14 p REE 14 dbxtoOl ns rm de amma en 14 debug uci nec eer MOI RI RE e tae Ea Ras 15 debugging kenerite reri ueri es RP IERI SS 14 define loas ge peri ba Reseed eee eed 4 dependence among products 19 diagnostic prod cts i I een 11 directive ninia ai eer RAE 4 domain specific modules 8 pl IRE ciel nibarsdsdite ba RR E iir 17 edit Command see 11 EDI DEBUGGER piret eedan eee a E RES 15 ELT DEBUGGER 2 4 enc a0 Ha Bales 14 OTOL na area ee T error fepOrt lndkdasegs e ERE RERNRRRAS EMI 11 21 executable program eee 3 execution monitoring eee 14 expert SySLel ilcvte
23. on and may be either a string or a file Files are specified by parenthesized odin expressions strings are not parenthesized cmd sets specs exe cmd diff result expected cmd sort u 4 2 stdout Standard Output from Processor Execution stdout A file containing the result of applying a filter to another file The filter is specified by the cmd parameter attached to the filtered file If no cmd parameter is attached to the filtered file then the result is simply the filtered file itself A typical situation is to use the generated processor to filter a data file data cmd sets specs exe stdout 4 3 output Files Resulting from Processor Execution output The execution directory after applying a filter to a file The filter is specified by the cmd parameter attached to the filtered file If no cmd parameter is attached to the filtered file then the result will be an empty directory A typical situation is to use the generated processor to filter a data file If the generated processor creates files as a side effect of processing the data these files will be in the derived directory data cmd sets specs exe output 4 4 run Execute the Processor in the Current Directory run Execution of a specified command line in a specified directory This derivation must be applied to a directory object and requires a cmd parameter see Section 4 1 cmd page 13 14 Products and Parameters Reference
24. oup of products Even though a set of specifications is consistent it may not be correct The testing prod uct group should be used to exercise the processor verifying that the specifications solve the proper problem Products and parameters in the document group provide formatted versions of specifications that can be put on paper or rendered as hypertext Finally the derivation group allows the user to obtain information about the details of how products are derived and influence the derivation process in certain ways Chapter 1 Processor Generation 3 1 Processor Generation Eli s task is to create a text processor that implements a set of specifications Two forms of that processor can be extracted from Eli an executable form and a source form The processor can also be tested without extracting it from Eli see Chapter 4 Testing page 13 Regardless of the ultimate disposition of the processor its behavior can be influenced in a number of ways by parameters 1 1 exe Executable Version of the Processor exe A binary file containing the executable program generated from the given specifications During specification development exe is used as a means of collecting error reports see Section 3 3 help page 11 pascal specs exe help When this derivation yields an empty result indicating that no errors were detected in the specifications the generated processor can be tested by requesting the stdout see Section 4 2 st
25. products see Section 4 6 Monitoring page 14 which automatically imply the monitor parameter For mongdb to be useful the debug parameter must also be used see Section 4 9 debug page 15 4 8 arg Supply Command Line Parameters arg item arg file The specified items are supplied as command line parameters to the generated processor when it is executed by mon or mongdb An item is any sequence of non white space characters other than apostrophes Items are separated by white space Any number of items may be specified 4 9 debug Request debugging information in object files debug If the debug parameter is used all compilations are given the g flag This causes the compilers to provide additional information for the source level debuggers dbx 1 and gdb See Section 4 5 Debugging page 14 In conjunction with the monitor parameter see Section 4 7 monitor page 15 debug enables the use of mongdb See Section 4 6 Monitoring page 14 4 10 printtokens Request Token Printing Code printtokens 16 Products and Parameters Reference If printtokens is specified the generated processor will print the source text coordi nates internal code and intrinsic value for each basic symbol as it is read This listing is useful to verify that the lexical analysis specification is correct and also to obtain a frequency distribution of the kinds of basic symbols appearing in a program Chapter 5 Producing Formatt
26. re not included 2 4 pgram Parsing Grammar pgram The parsing grammar requested by the pgram derivation is the input to the parser generator This includes the integer encodings of the terminal symbols any directives supplied by the user to direct the automatic error correction of the parser and each of the BNF rules in the concrete syntax with associated actions These actions include actions supplied by the user as well as actions generated to construct an abstract syntax tree Note that the mapping process may cause the injection of certain chain rules due to BOTTOMUP constraints specified in the attribute grammar These injected rules do not appear in the result of the consyntax derivation which makes pgram the most appropriate derivation to consult when trying to resolve parsing conflicts which may have resulted from the injection of these chain rules See Section BOTTOMUP in Syntactic Analysis 8 Products and Parameters Reference 2 5 kwd Recognize Specified Literals as Identifiers file gla kwd Specifications that force literals whose lexical structure is defined by file gla to be handled specially by the generated scanner Normally each literal found in the context free grammar is recognized explicitly by the scanner as the specified character sequence This is in contrast to identifiers denotations and comments whose lexical structures are defined by regular expressions The literals are defined by their appear
27. rseseefesbeesppeele T ENEA 19 EXPLO O copadas da Syd wp dd emendet 9 explanation of reports 0000 11 external modifications informing Eli 19 F feedback innen ee ae 19 EOS a anes a ae 4 formatted File nun en anna 17 F nnelWeb ue ns ea De Id PWG erik E cone ne een deb ed Gnd seit 3 P WHOM ROO cae tonne ete boat ee 17 TWIEX PP nn rein df G o E 14 GDB ace esos dU ED ee ON 14 A s ese kant 12 generated files 0 e eee 12 generation parser 0 cee eee isar 12 generic modules naming instances 10 generic modules user constructed 8 GNU debugger lr ce ace demure ome 14 H header fil6 uius gs c aA TERRE 3 help nica sk RRERRR RR ERR IA APRI 11 hypertexti ins nedueeeenI PEE en RE did I identifier outp t user 4 La ir r d eR aia 4 a Cy Co u dar rra ci 4 INCONSISTENCIES cides eis ceed ee dee en diese 11 TOPE cu e rt ner qe please 19 INSt os ccc A REN PER Ree Lees Rea Ss 8 1nBtanc6e e I as 10 instantiatiOn c m e aeaa asi 8 interactive ppc ave ve Ep EE 11 14 intermediate products s esse s 19 internal code e oro E dar 16 intrinsic UA 16 invoking type gnrc scripts sss 8 K keywords varas dan 8 p C 8 22 L last modification eld e as 19 letters case Of 4 E 24 ete l nes staaten 8 Library routine Itm ies epe IRR 3 LogLewel eee 4 ad 19 Toner CABO Lesen ana 4 M
28. s some times useful to try the other generator when one produces a message you don t understand Remember however that PGS accepts a wider class of grammars Thus COLA may report errors for a grammar and PGS may not One of the two parser generators is selected as the default at the time the Eli system is generated The default parser generator will be used if the parser parameter is absent A request specifying parser only will cause the non default parser generator to be used Specifying parser pgs will cause PGS to be used while specifying parser cola will cause COLA to be used The default parser generator can be changed by changing the shell scripts parserOut sh bnfOut sh and infoOut sh in directory elipkg parser Sometimes it is desirable to not have a generated parser For example the user may be building a tree for attribution using hand written code or code produced by an application external to Eli Specifying parser none will cause Eli not to generate a parser 1 8 nomain Omitting the main program nomain Normally Eli generates a main program that invokes the generated components in an appropriate order Sometimes the user wants to have more control by providing their own main program In this situation nomain should be specified to omit the standard Eli main program Chapter 2 Generating Specifications 7 2 Generating Specifications Sometimes a common problem can be solved by a collect
29. source text coordinates ss 16 Status ciere hib em eh ic dl SUtQOUt u ne crab 13 STOPAFTERBADPAR SE osos aa 4 E A A tesa eet ee eels 19 TOXINT O23 os bik on oe nee 17 TIPO Miri I7 bype gurce Files euere 8 U Upper CASE cua riada Ub nd 4 W WAL Ing eure 11 warning message ci nat 11 WAR Ni 1 Abedin inte he e A EU ei 17
30. tems may be specified The following items are pre defined STOPAFTERBADPARSE Generate a processor that will terminate after parsing if syntax errors are de tected see Section Improving Error Recovery in the Generated Parser in Syntactic Analysis 1 6 ignore Do Not Verify include Files ignore path Eli normally verifies the presence of files requested by include directives in any file that it processes The ignore parameter tells Eli not to verify the presence of such files if their full names begin with path If a derivation does not specify any ignore parameters ignore usr include is assumed This assumption is not made if any ignore parameters are given explicitly 1 7 parser Choose the parser generator parser parser pgs parser cola parser none Chapter 1 Processor Generation 5 Eli incorporates two parser generators PGS and COLA Both produce parsers from LALR 1 grammars and the parsers they produce recover automatically from syntactic errors A PGS generated parser does not reduce by chain productions This means that it accepts some grammars that are not LALR 1 and the generated parser is faster than a COLA generated parser for languages with many precedence levels in expressions Parsers generated by COLA include more information in error messages about expected tokens than those generated by PGS do The error reports provided by the two parser generators differ somewhat and it i
31. ule file gnrc inst A specification consisting of one or more files is generated from file gnrc This product is normally used to instantiate the common problem solutions that have been stored in the library see Section Module Instantiation in Specification Module Library elipkg Name AlgScope gnrc inst Here the path elipkg Name accesses the portion of the library devoted to problems arising in the context of name analysis see Section Name Analysis Library in Specification Module Library Name Analysis Type gnrc files can be supplied by a user They are simply shell scripts that carry out whatever actions are needed to instantiate a generic specification Thus a user of Eli can construct generic specifications appropriate to a specific domain and use them exactly like library specifications Scripts appearing as type gnrc files are invoked with up to three parameters The first parameter is the sed 1 program the second parameter is the string specified by instance and the third parameter is the string specified by referto When the script is invoked Chapter 2 Generating Specifications 9 its full path name is used Therefore the script can determine the directory in which it is stored and access specific files in that directory Here is an example of a type gnrc file elipkg Name AlgScope gnrc bin sh Id pp tnf v 2 14 2008 06 12 21 15 29 profw Exp Copyright 1994 AG Kastens University Of Paderborn
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