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1. When the interpreter receives a query it starts searching for solutions Any output produced by the query during its execution is immediately displayed When the query finally succeeds the interpreter displays the variable bindings When there were no variables in the query the interpreter displays Yes Hello World Yes 2 The interpreter now checks whether the query left some choice points When no choice points are left the interpreter immediately returns to the Prolog prompt Let s now turn to our second query The second query will contain variables so that we will see how variable bindings will work Bo Ne Ike oe aT When the execution of the query succeeds for the first time the interpreter will show the vari able bindings Again the interpreter will check whether some choice points are left Since in the case of this query some choice points are left the interpreter will wait for further instruc tions from the end user The end user can choose upon the following options EOF Exit the current session Redo the query and possibly display more solutions Don t redo the query no more solutions will be displayed Display this help text lt Goal gt Execute the lt Goal gt and prompt command again If the end user chooses a goal this goal will be executed and the end user will be prompted again The side effect of the goal can control the i
2. B pizzat o X 9 5 6 7 1 0 8 2 No February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 12 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 2 4 Rabbits Example Jekejeke Prolog allows the grouping of predicates to modules The given example shows mutual recursion among modules We are going to work on a problem of mathematical biol ogy A certain man put a pair of rabbits in between walls How many pairs of rabbits can be produced from that pair in a year if it is supposed that every month each pair begets a new pair which from the second month on becomes productive We will model the problem by two predicates adults 2 and babies 2 Each predicate has a first argument for mount count starting with zero and second argument for the corresponding size of the population counted in rabbit pairs The dynamics of the two populations is de picted below In each month the number of adults grows by the number of babies On the other hand in each month there are new babies in the number of adults Growth Reproduction BB BS We will place the predicate adults 2 in a module named cage and the predicate babies 2 ina module named nest In Jekejeke Prolog a module resides in a Prolog text The Prolog text has to start with the module 2 directive This directive states the name of the module and the exported predicates The declaration reads as follows for the cage module module cage adu
3. Examples abolish foo 1 Yes 2 abolish infix gt Yes The predicate abolish 1 allows a predicate turning it non existent again The same predicate can be also used to remove operators by using indicators prefix 1 postfix 1 and infix 1 The predicate will attempt to remove own user clauses of the predicate and only remove it if no system or foreign user clauses remain If still some of the aforementioned clauses remain the predicate stays existent and non empty The following dynamic database predicates are provided dynamic P ISO 7 4 2 1 The predicate sets the predicate P to dynamic thread_local P The predicate sets the predicate P to thread local group_local P The predicate sets the predicate P to group local clause H B ISO 8 8 1 The predicate succeeds with the user clauses that match H B The head predicate must be dynamic or thread local retract C ISO 8 9 3 The predicate succeeds and removes with the user clauses that match C The head predicate must be dynamic or thread local retractall H Corr 2 8 9 5 The predicate succeeds and removes the user clauses that match the head H The head predicate must be dynamic or thread local February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 71 of 134 Jan Burse Language Runtime XLOG Technologies GmbH asserta C ISO 8 9 1 The predicate inserts the clause C at the top The head predicate must be dynamic o
4. abs 1 X abs 1 X Error Argument should be a number found 1 abs 2 The following arithmetic operations are recognized in evaluations X ISO 9 1 7 If X is a number then returns the sign inversion of X X TC2 9 1 3 If X is a number then returns X unchanged abs X ISO 9 1 7 If X is a number then returns the absolute value of X sign X ISO 9 1 4 If X is a number then returns the sign of X float X ISO 9 17 If X is a number then returns the conversion of X to a float decimal X If X is a number then returns the conversion of X to a decimal float32 X If X is a number then returns the conversion of X to a float32 X Y ISO 9 1 7 If X and Y are both numbers then the function returns the addition of X and Y X Y ISO 9 1 7 If X and Y are both numbers then the function returns the subtraction of X by Y X Y ISO 9 1 7 If X and Y are both numbers then the function returns the multiplication of X and Y X Y ISO 9 1 7 If X and Y are both numbers then the function returns the division of X and Y X Y TC2 9 3 10 If X and Y are both integers then the function returns X raised to the power of Y February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 78 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Rounding Operations We supply a number of binary and unary operations that deal with rounding We find different rounding modes and we also
5. TC2 8 3 10 The predicate succeeds when X is a ground term i e contains no variables February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 87 of 134 Jan Burse Language Runtime XLOG Technologies GmbH sys_get_variable_names L The predicate succeeds in L with the current variable names from the top level query excluding non variables and duplicates acyclic_term X TC2 8 3 11 The predicate succeeds when X is an acyclic term i e contains no cycles February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 88 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Lexical Comparison Lexical comparison allows comparing terms without an attempt to instantiate the terms These predicates are therefore meta logical The predicates 2 and 2 perform an equality test The predicates lt 2 lt 2 gt 2 and gt 2 use a linear ordering based on a lexical comparison The lexical comparison first looks on the basic type of the in volved terms The ordering of the basic types is as follows variable lt decimal lt float lt integer lt reference lt atom lt compound Variables are ordered according to their internal instantiation numbering Integers floats and decimals are arithmetically ordered But there is no mixing of integers floats and decimals Atoms are ordered according to their internal character representation For compounds first the arity is compared then the functor is com
6. Yi moCtle a YY moct y Uy Ia Example g corcicm nelo 0 OlEHelalone mn nello imrerprecer a fo is a foreign predicate directive Not all declared classes or parameter types have to be fully qualified The below class names can be directly used without specifying the package name All formal parameters not of class Term cause a range check and or conversion of the actual argument A formal pa rameter of type BigDecimal or BigInteger causes a widening whereas a formal parameter of type Integer Float or Long causes a range check The supported primitive datatypes are handled analogously The Java method constructor or field might also have one of the above classes or primitive types as a return type By return ing anon null object the Java method constructor or field can indicate success and the inter preter will unify the object with the last argument of the corresponding predicate By returning a null the Java method or field can indicate a failure A Java method might also have a boolean or a void return type The return type boolean can indicate success or failure without returning an object The return type void always indicates success without returning an object For non static methods or fields an additional argument for the receiving object is added to the front of the foreign predicate A formal parameter of type Interpreter is needed for foreign predicate that change variable bindings A formal parame
7. atom_length X Y ISO 8 16 1 The predicate succeeds when Y is the length of the atom X atom_concat X Y Z ISO 8 16 2 The predicate succeeds whenever the atom Z is the concatenation of the atom X and the atom Y sub_atom X Y Z U sub_atom X Y Z T U ISO 8 16 3 The predicate succeeds whenever the atom U is the sub atom of the atom X starting at position Y with length Z and ending T characters before atom_chars X Y ISO 8 16 4 If X is a variable and Y is a character list then the predicate succeeds when X unifies with the corresponding atom Otherwise if X is an atom then the predicate succeeds when Y unifies with the corresponding character list atom_codes X Y ISO 8 16 5 If X is a variable and Y is a code list then the predicate succeeds when X unifies with the corresponding atom Otherwise if X is an atom then the predicate succeeds when Y unifies with the corresponding code list char_code X Y ISO 8 16 6 If X is a variable and if Y is a code then the predicate succeeds when X unifies with the corresponding character Otherwise if X is a character then the predicate suc ceeds when Y unifies with the corresponding code number_chars X Y ISO 8 16 7 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 91 of 134 Jan Burse Language Runtime XLOG Technologies GmbH If X is a variable and Y is a character list then the predicate succeeds when X unifies with the corresponding number Othe
8. oss ea The interpreter will move between these goals via backtracking until a solution is found The interpreter can also be used to return multiple solutions Since modern Prolog systems and modern machines do more than 2 mega logical inferences per second many small problems can be solved in time We also apply this method to our letter puzzle So that we don t look too stupid we will enumerate intelligently Simply enumerating all possi ble digit combinations would lead to 108 possibilities What we will do we will only enumer ate permutations of the available digits which will lead to 8 possibilities We do make use of the oneof 3 predicate which non deterministically picks an element from a list The generator for the permutations then reads as follows assign List List assign Nig asserena Ih BS CinSone ih X IN aeea IRD The above predicate is then used to assign digits to the letters More details about the gener ation phase can be found in the appendix The test phase is now simply a code phrasing of the problem statement We will look for a solution where M and S are non zero And we look for a solution where the addition holds These conditions read as follows nis oll Be pee aI SGO 1000 S 100 H 1O N 1000 M 100 0 10 R OOO Oc Mae eel O OO Ome r MOON i MOs K FU ll ll We can now run the Jekejeke Prolog interpreter to find the sole solution
9. 1150 fx static 1105 xfy 1100 xfy 1050 xfy gt 1050 xfy gt 900 fy 700 xfx gt 700 xfx 700 xfx 700 xfx e 700 xfx lt 700 xfx 700 xfx lt 700 xfx lt 700 xfx 700 xfx lt 700 xfx 700 xfx 700 xfx gt 700 xfx is 700 xfx gt 700 xfx gt 600 xfy 600 xfy 500 yfx 500 yfx A 500 yfx 500 yfx V 400 yfx i 400 yfx 400 yfx xor February 23 2019 Language Runtime runtime quali runtime quali runtime quali arithmetic compare arithmetic compare arithmetic compare arithmetic compare arithmetic compare arithmetic compare arithmetic eval Module runtime logic runtime dynamic bootload load bootload module runtime meta runtime meta runtime dynamic bootload load bootload load bootload module reflect pred runtime logic runtime logic runtime logic runtime logic runtime logic structure lexical structure univ structure univ arithmetic compare arithmetic compare structure lexical arithmetic compare structure lexical structure univ structure lexical arithmetic compare structure lexical structure lexical arithmetic eval arithmetic compare arithmetic compare runtime quali runtime quali arithmetic elem arithmetic bits arithmetic elem arithmetic bits arithmetic elem arithmetic round arithmetic bits jekejeke_lang_run_2019 02 _01_e docx XLOG Technologies GmbH Page 131 of 134 Jan Burse 400 yfx 400 yfx 400 yfx 400 yfx 400 yfx
10. float32 X The predicate succeeds when X is a float32 float64 X The predicate succeeds when X is a float64 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 86 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Term Variables The test predicate ground 1 checks whether the given term is ground This means that no un instantiated variable occurs in the term The predicate term_variables 2 allows collecting the un instantiated variables that occur in a term The predicate will thus return an empty list if the term was ground Finally the predicate sys_term_singletons 2 collects the un instanti ated variables that only occur once They are a subset of all the variables that occur in the term Examples P SiS Goel KOTELOA Y 2 1X K p X Y ROMS VSMC Odile Gato alles KSN p o I PN Further there are predicates to deal with existential quantifiers The existential quantifier is represented by the 2 operator In a goal X1 Xn K we call K the kernel of the goal and the variables K subtracted by the variables of Xj Xn the global variables of the goal The predicates sys_goal_kernel 2 and sys_goal_globals 2 cater for the determination of the ker nel and the global variables of a goal An alternative to using the VAR lt number gt construct is dynamically creating a variable names map This has the advantage that the construct itself can be written out The predi cate sys _numbe
11. module class Method module subclass Method gt reexport class Methods The Jekejeke Prolog 2 is already polymorphic The reexport 1 directive will make all the methods of the parent class of a subclass visible in the subclass itself This allows for the ad ditional benefit of code sharing in a parent class of a subclass if the code is common for mul tiple subclasses We will implement a class basset with a different barking module basset barking 2 reexport dog override barking 2 barking _ woof In the above Prolog text the directive override 1 is an extension by Jekejeke Prolog and is necessary to suppress the warning that a re exported predicate is overridden However this exactly what we want to do in the present example implement a different barking We can send the bark command to a basset dog basset lafayette bark lafayette says woof Nels Classes defined as above retain all the advantages of the Jekejeke Prolog module system They can be automatically reloaded by the make O command Further it is possible to debug classes as if they were ordinary Prolog texts Since methods are Pythonesk predicates it carries over to set spy points and break points without restrictions February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 18 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 3 Prolog Conversations The Jekejeke P
12. 0 24 e References added stream section and clause expansion section updated Jan Burse November 13 2011 0 25 e Body conversion higher order and fruits example section introduced Jan Burse February 16 2012 0 26 e Message fixes conversations integrated and few enhancements February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 4 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Jan Burse June 4 2012 0 27 e Taxonomy example introduced and few enhancements Jan Burse July 16 2012 0 28 e Money example introduced and few enhancements Jan Burse August 22 2012 0 29 e Flag example introduced and few enhancements Jan Burse September 06 2012 0 30 e Aggregate predicates introduced and few enhancements Jan Burse October 30 2012 0 31 e Index section call site transfer section and few enhancements introduced Jan Burse January 12 2013 0 32 e Random functions introduced and stability analysis removed Jan Burse May 07 2013 0 33 e Newsys_notrace flag hierarchy and new lambda operator introduced Jan Burse June 05 2013 0 34 e Surrogate pairs introduced and quote flags made settable Jan Burse July 23 2013 0 35 e Pseudo modules introduced Jan Burse December 02 2013 0 36 e Pseudo module visibility for foreign predicates introduced Jan Burse February 03 2014 0 37 e New decimal compression build system and file options introduced Jan Burse Marc
13. 1 Language Reference Jekejeke Prolog 0 8 1 XLOG Technologies GmbH Switzerland February 227 2010 Trademarks Jekejeke is a registered trademark of XLOG Technologies GmbH February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 2 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Table of Contents Te WAMRO GUC ION E O EE sole seaeed cheater den E EEE 7 2 Prolog EXAIMPleS okrea E a E E E E a ce deluees Dedede tenons R EE 8 2 1 Animals Example SOS 6 eee Se ia i lan ik Cols ok es Se ee a oad eA id Si eae 9 2 2 Primes Example sO lyase vs ceca ec as eee cee ce at aS 10 2 3 Money Example ISO arrn a e AE EEEE E AE N 12 2 4 Rabbits EXample ie reenen A EE AE deel AEE EN 13 2 5 Parallel Example aae a aq e EE E AERE EE 15 260 P nd Example n E E EE a AEE E E EEA 17 DB Prol g Conversation da eae ek tech ra aac dea a aAA EE aa ARAE as deen Sea 19 SA e STONE EP rasia eaaa hatin Coon head raa ca ge dee Mad sada rE aaae E NEEE 20 3 2 Error Handig tas ode eh dtesectinaa ated beget Roar A E E AE E ameter 22 3 3 So rce CONSUME AG sse ee ana a aE a e A EE E E ceva R a 24 3 4 Interrupt Handling soeeennneeeeeeeeennntnenesseeennrrnnrrssrrtrnrrnnrtssrrerrtnnrtsseerrerrnnnesserrnn nnne 25 3 5 Compatibility Matrix 2 c 2 c 2c2 cee cdeceedsscce ne secceeeessseacernedeeseenssanseenestnenenasensqesegoneeensdanseess 25 Be Prolog Syntax eine a Na teste i a Sass he cle aeae aa aae hee eau A Sea naehelataautent 26 Al To
14. 200 fy 200 fy 200 fy 200 xfy 200 xfx 100 yf February 23 2019 Language Runtime arithmetic bits arithmetic round arithmetic bits arithmetic round arithmetic round arithmetic elem arithmetic bits arithmetic elem arithmetic elem arithmetic trigo arithmetic eval jekejeke_lang_run_2019 02 _01_e docx XLOG Technologies GmbH Page 132 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Pictures Es konnten keine Eintrage fur ein Abbildungsverzeichnis gefunden werden Tables Table 1 Compatibility Matrix for Interactions cccceeeeeeeeeeeeeeeee teeter eeeeeeenaaeeeeeeeeeeeeeeeaaees 25 Table 2 Compatibility Matrix for the Token Syntax ccccccccccceccecceeeeeeeeeeeeeeeeceeeeeeeeeeeeeeeeess 36 Table 3 Compatibility Matrix for the Term Syntax ccccceeeceeeeeteeeee eee eeeeeeneeeeeeeeeeeteneeaaees 41 Table 4 Compatibility Matrix for the Text SYNtax ccccccccccccccccecceeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeseneess 44 Table 5 Compatibility Matrix for the Kernel Theory cccccccceccccccccceeeeeceeeeeeeeeeeeeeeeeeeeeeeess 63 Table 6 Compatibility Matrix for the Runtime Theory cccccccceccccececeeeeeeeeeeeeeeeeeeeeeeeeeeeess 74 Table 7 Compatibility Matrix for the Arithmetic TN OFy cccececeeeeeeeeeeeeenteeeeeeeeeeeeeeeaaees 84 Table 8 Compatibility Matrix for the Structure Theory cccccccccccecccceceeeeeeeeeeeeeeeeeeeeeeeeetess 93 Table 9 Operator MOOS y 5
15. 4 Ay Ash cen Z S O 5 D o L Age Ah thy EAN The idea is now a predicate perfect 2 which puts everything together This predicate will first determine the half of the number then collect the divisors and finally compute the sum and check whether it equals the given number Our predicate should answer yes for 28 and for non perfect numbers it should answer no FONE OX B Ye aS NG 2 reeL kA bcewee n ey Zt X ran A Olean sum ligt in X perfect 27 No perfect 28 Yes The first four perfect numbers were the only ones known to early Greek mathematics the mathematician Nicomachus had noted 8128 as early as 100 AD The above predicate is a brute force solution and does not use much number theory It can already find the perfect numbers between 1 and 10 000 in a reasonable time February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 15 of 134 Jan Burse Language Runtime XLOG Technologies GmbH between 1 10000 X perfect X x R 2 a X 496 XS olo p No time between 1 10000 X perfect X fail true ope 4 O6 oimS CCm Enreadeepue Oe ms Current O2 0L 19 lhssis25 time between 1 20000 X perfect X fail true Up 11 818 ms GC 94 ms Thread Cpu 11 672 ms Guise mite O02 OnlW MEO mGA Yes One way to speed up the search is to use more CPU power We will now explain how Jeke jeke Prolog can help in running a sear
16. Oeil 234 72 arIo Y Ocllooa 2 If an integral value is between 2431 and 231 1 then the Java Integer is used instead of the Java BigInteger Similarly if a decimal value has scale 0 and a mantissa between 2 63 and 263 1 then the Java Long is used instead of the Java BigDecimal The decimal scale is re stricted to 31 bits The float mantissa is bounded and approximated to the precision The small respectively large float binary scale is restricted to 8 bits respectively 11 bits A negative zero is mapped to a positive zero A NaN or infinity irrespective of its sign is considered outside of the do main and leads to an error Example user feal ite Onesleculin OF N ime eo Ice OX YO 8 gt 2eSO Tal aley Mik ieereiwomel sl wi MW Bee Mew aD P X ALS ieeieiv aealelll 41 M Bal The predicate is 2 can be used to evaluate a term consisting of evaluable functions and num ber constants Thanks to bridging an evaluable function can also be defined by ordinary Prolog clauses for the corresponding predicate The evaluable function will only deliver the first result of the corresponding predicate The following built in predicate is provided for arithmetic domains X is Y ISO 8 6 1 The predicate succeeds when X unifies with the evaluation of Y X V1 5 Yn Z The predicate succeeds when Z unifies with the element of term with the subscripts Yi Yn for 1 lt n lt 7 The term X ne
17. RSTO le eS ete NT 18 remove Is P Nis The first rule states that nothing needs to be removed from the empty list The second rule removes the first element of a list if it is a multiple of the given number and then continues recursively Otherwise the third rule will keep the first element and continue recursively We can test it also for m 16 and sift two times February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 10 of 134 Jan Burse Language Runtime XLOG Technologies GmbH integers 2 16 X remove X 2 Y remove Y 3 2Z X 2 Sp 4 Y Sg Sp 7 B Sp Fo 2 o Sp Oe Up By Be IO Ll 12 13 14 Ts 16 7 Yo Al I3 LSI iby L3 We now need a predicate that does the iteration of the crossing out and the collection of the prime numbers until we have reached the stopping condition Again we will have input and output argument positions of the predicate To check the stopping we use the arithmetic mul tiplication function Sabre i LS Hiie TE Ls ts TS Mion la Saline a Telp miela E Bs ss remove Is I New sift New High Ps The first rule expresses our stopping condition When we have reached p p gt m we will return all the remaining numbers The second rule will keep the first element does one crossing out and continues recursively We can test it for m 16 Q aboneerefenass Ap LO y Sie 047 1k 4 5 eS S Che Se Ge Ue Sin PSs INO lik
18. The predicate succeeds whenever A succeeds The goal argument A is converted before calling February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 54 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The following predicate properties for body conversion are provided sys_body The property indicates that the meta predicate is traversed by body conversion The property can be changed for user predicates sys_rule The property indicates that the meta predicate is traversed by rule conversion The property can be changed for user predicates The following Prolog flags for body conversion are provided sys_body_conversion The legal values are on and off The flag indicates whether the body conversion is en abled for the knowledge base The default value is on The value can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 55 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Control Predicates The backtracking control flow can be modified by the cut 0 The cut will remove the choice points from the head to the cut including a head choice point Common programming pat terns involving the cut are provided in the forms of the predicate once 1 and 1 Both predicates will remove any backtracking from the goal argument The interpreter has the capability to interrupt its normal flow by exception handling An inter ruption happens when an exception is thrown or when a signa
19. 134 Jan Burse Language Runtime XLOG Technologies GmbH Prolog Texts Prolog texts have the syntax of a consult text see section 4 3 When consulted the contained facts and rules are asserted The encountered head predicates of the facts and rules are de clared static by default Further any directives in the theory text are executed in the order they appear These directives might additionally declare foreign predicates Upon consulting again a source the related declared predicates are first abolished The consult performs various style checks The facts and rules are checked for singleton var iables Singleton variables need to be input in the form of anonymous variables _ The facts and rules for the same head predicate need to form one block The directive discontiguous 1 allows exempting a predicate from this style check The special file name user can be used to consult from the standard input Normally the facts and rules for the same head predicate come from one source only The directive multifile 1 allows exempting a predicate from this style check Multi file predicates behave differently during re consult If a declared predicate spans multiple sources only the clauses belonging to the re consulted source are retracted The defined predicate will only be abolished when it does not belong to any source anymore The following theory files predicates are provided ensure_loaded R ISO 7 4 2 8 The predicate ensures that the
20. 2 discontiguous 1 div 3 dynamic 1 e 1 ensure_loaded 1 exit O exp 2 float 1 float 2 float32 1 float32 2 float64 1 floor 2 foreign 3 Language Runtime XLOG Technologies GmbH bootload path bootload path arithmetic trigo structure vars structure univ arithmetic trigo runtime dynamic runtime dynamic arithmetic trigo arithmetic trigo structure type structure atom structure atom structure atom structure atom structure atom reflect foreign reflect pred structure type runtime distributed runtime distributed reflect foreign runtime session runtime logic structure type arithmetic round reflect foreign structure atom runtime dynamic runtime session structure lexical structure type bootload load arithmetic trigo reflect oper reflect oper reflect pred bootload engine reflect source reflect source structure type arithmetic elem bootload load arithmetic round runtime dynamic arithmetic trigo bootload load runtime session arithmetic trigo structure type arithmetic elem structure type arithmetic elem structure type arithmetic round reflect foreign February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 127 of 134 Jan Burse foreign_const 3 foreign_constructor 3 foreign_fun 3 foreign_getter 3 foreign_setter 3 halt 0 halt 1 horde 1 horde 2 include 1 instance_of 2 integer 1 integer 2 integer16 1 integer16_and_not_integer8 1 integer32 1 integer32_and_not_integer16 1 int
21. Jan Burse Language Runtime XLOG Technologies GmbH Interpreter State Some interpreter state can be queried and updated The predicate current_prolog_flag 2 al lows accessing an interpreter attribute The predicate set_prolog_flag 2 allows updating an interpreter attribute The predicates halt 0 1 allow exiting the current process The predicates begin _module 1 and end_module 0 can be to open respectively close a local module For a consulted file the predicate begin_module 1 will also do first a clear of the local module and the predicate end_module 0 will do a style check of the local module The following interpreter state predicates are provided current_prolog_flag F V ISO 8 17 2 The predicate succeeds for the value V of the flag F set_prolog_flag F V ISO 8 17 1 The predicate sets the flag F to the value V halt ISO 8 17 3 halt N ISO 8 17 4 The predicate without arguments terminates the interpreter with exit value zero The unary predicate terminates the interpreter with exit value N welcome version The predicate displays a version banner begin_module N The predicate begins a new typein module N end_module The predicate ends the current typein module February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 106 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Capability Plug Ins Capabilities bundle a set of predicate definitions Capabilities are also able to bundle special bu
22. M E The function evaluates the expression E by qualifying the function name of E by the module name M The evaluation is performed in the same call site as the colon nota tion R E The function evaluates the expression E by qualifying the function name of E by the module name of R and prepending R itself The evaluation is performed in the same call site as the colon notation February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 68 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Logical Predicates When a goal belonging to a defined predicate is invoked a new frame is created When the interpreter encounters a cut it will remove the choice points inside the frame To instruct the interpreter that cuts can nevertheless propagate a defined predicate can be marked as cut transparent via the predicate property sys_nobarrier 1 Examples B 16 elf Of Joye ksaj ip P X a Ip MS is X Gl Some of the predefined logical predicates are cut transparent in all arguments This includes the predicates 2 and 2 Others are only cut transparent in a few arguments This in cludes the predicates gt 2 and gt 2 and also the special forms in connection with the predicate 2 Others such as call 1 once 1 and 1 are not cut transparent at all The following logical predicates are provided A B ISO 7 8 6 The predicate succeeds whenever A or B succeeds Both goal arguments A an
23. New miscellaneous definitions section and new indexes section Jan Burse May 16 2016 0 54 e Some predicates moved from Jekejeke Minlog to here Jan Burse June 23 2016 0 55 e Different error message for undefined in bridging Jan Burse August 05 2016 0 56 e New module distributed Jan Burse September 25 2016 0 57 e New evaluable expression meta specifier Jan Burse December 17 2016 0 58 e Some improvements in the decimals Jan Burse April 23 2017 0 59 e Some improvements in the residues Jan Burse July 18 2017 0 60 e Some improvements in the atoms Jan Burse October 11 2017 0 61 e New variable names handling Jan Burse February 01 2018 0 62 e New help utilities introduced Jan Burse May 10 2018 0 63 e Simplification and changes from hierarchical knowledge bases Jan Burse July 05 2018 0 64 e Tagged structures and zero argument syntax introduced Jan Burse September 28 2018 0 65 e Improved module reflection Jan Burse November 19 2018 0 66 e Better nursery for load balancing Jan Burse January 04 2019 0 67 e Some improvements in the atoms and pseudo strings Jan Burse February 01 2019 0 68 e The tty flags have been removed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 6 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 1 Introduction This document gives a reference of the Jekejeke Prolog programming lan
24. Runtime XLOG Technologies GmbH sys_source_name N The property indicates that the source has the module package and name N The property is single valued and can be missing The property can be changed for user sources sys_timing T The property indicates the time spent for consult ensure loaded or unload in milliseconds The property cannot be changed sys_link S M The property indicates that this source is linked to the source S with visibility and export mode M The mode M can take the values use_module reexport sys_auto_load sys _load_resource and sys_parent_module The property is multi value and can be missing The property cannot be changed package P The property indicates that this source has prefix P and that the name of the source has also this prefix The prefix P can be a compound with functor library 1 or foreign 1 The argument of the compound should be a package The property is single valued and can be missing The property can be changed use_package P The property indicates that this source has prefix P but it doesn t put forward a prefix for the source name The prefix P can be a compound with functor library 1 or foreign 1 The argument of the compound should be a package The property is multi value and can be missing The property can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 116 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility Matrix The fol
25. The quaternary predicate allows specifying a locale C February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 89 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Building Unification Term building allows the access and construction of arbitrary terms Since some of the predi cates require arguments to be instantiated these predicates are not logically complete Nev ertheless most of the predicates are flexible enough so that they can be called in both direc tions Namely they can be called with the modes and whereby indicates an instantiated argument For performance reasons the interpreter performs unification without occurs check This can result in cyclic structures which are not logically sound in the usual Herbrand model interpre tation The cyclic structures might result in infinitely looping programs or in a looping during term output For programs that need a logically sound unification a special predicate is pro vided which does only instantiate variables when the check fails The following term building and unification predicates are provided X Y ISO 8 5 3 If X is atomic then the predicate succeeds when Y unifies with X If X is the com pound F Ai An then the predicate succeeds when Y unifies with F Aj An If Y is C and C is atomic then the predicate succeeds when X unifies with C If Y is F Ai An and F is an atom then the predicate succeeds when X
26. X gt gt Y ISO 9 4 1 If X and Y are both integers then the function returns X shifted by Y places right February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 81 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Trigonometric Operations The trigonometric operations are defined for integers floats and decimals If the argument is an integer it is widened to a float before computing the operation On the other hand if the ar gument is a decimal it is narrowed to a float before computing the operation Widening from decimal to float might fail with an exception since the unbounded decimals have a greater range than floats If the argument of a trigonometric operation is outside of its domain then an undefined evalu ation error is thrown Further when the mathematical result exceeds the range of the float then a float overflow evaluation error is thrown The throwing of an exception is preferred over returning a float with the meaning of not a number NaN negative infinite Inf or posi tive infinite Inf The following trigonometric operations are recognized in evaluations sin X ISO 9 3 2 Returns the float representation of the sine of X argument must be in radians cos X ISO 9 3 3 Returns the float representation of the cosine of X argument must be in radians tan X TC2 9 3 14 Returns the float representation of the tangent of X argument must be in radians asin X TC2 9 3 11 Returns t
27. Yy OCE Chic ma MOM a AT wmi Coce mo Til ae Glaiepatic Mex Ciee Mex Cheie Mex Ceto hex code gt Weal nex Chigit 1 hex igite j ANE hex digit SSS OREA AWA Boe MIS Ip Wem og bh ats Examples Welo VAioli kine lakine 2 very long code list UN Srna U uD83D uDE02 oe is a double quoted string is a back quoted string ol is a double quoted string is a single quoted string is a double quoted string oe ol foe Strings can contain escape sequences that start with the backslash After the backslash escape codes control symbol or a meta code can follow The escapes codes allow octal codes uni codes and hexadecimal codes Surrogate pairs are automatically combined into a single code point The octal code is simply a sequence of octal digits terminated by the backslash The uni codes start with the Unicode indicator u and require exactly four hexadecimal digits The hexadecimal code starts with a hexadecimal indicator x followed by a sequence of hexa decimal digits terminated by the backslash There are control symbols for the alert a the backspace b the carriage return r the form feed f the horizontal tab t the new line n and the vertical tab v Among the meta codes we find the backslash single quote the double quote and the back quote When escaped they simply denote them Strings are
28. a module context operator ISO 4 Defines level of expression inside parenthesis as 1201 ISO 5 Special list operator syntax comes as block operator SWI7 6 The block operator uses a different term building SWI7 7 Special set operator syntax comes as block operator SWI7 8 The block operator uses a different term building SWI7 9 Without space to the it s a native dictionary SWI7 10 The zero argument uses a different term building SWI7 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 41 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 4 3 Text Syntax This syntax describes the grammar that forms Prolog texts and queries from term se quences We find the following topics e Consult Syntax Consulted Prolog texts consist of directives and clauses e Session Syntax The end user interacts with the Prolog interpreter via a session e Compatibility Matrix SO DEC10 compatibility issues of this syntax February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 42 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Consult Syntax A theory text is a set of lines usually read in from a file Each line is first converted by the term syntax and then interpreted according to the text syntax The main purpose of a theory text is to provide an ordered collection of premises Among the premises we find facts and rules Rules consist of a head and of a body separated by the implicat
29. are variable atom integer float and compound The Jekejeke Prolog system adds to these data types the data types reference and decimal Examples z callable p X Y Yes P eul aloe iL No We find elementary test predicates such as var 1 atom 1 integer 1 float 1 and compound 1 For the Jekejeke Prolog specific data types we find the test predicates reference 1 decimal 1 float82 1 and float64 1 We find also test predicates that group different data types together such as nonvar 1 atomic 1 number 1 and callable 1 The following type testing predicates are provided integer X ISO 8 3 3 The predicate succeeds when X is an integer float X ISO 8 3 4 The predicate succeeds when X is a float atom X ISO 8 3 2 The predicate succeeds when X is an atom compound X ISO 8 3 6 The predicate succeeds when X is a compound reference X The predicate succeeds when X is a reference decimal X The predicate succeeds when X is a decimal number X ISO 8 3 8 The predicate succeeds when X is a number i e an integer a float or a decimal callable X TC2 8 3 9 The predicate succeeds when X is callable i e an atom or a compound atomic X ISO 8 3 5 The predicate succeeds when X is a constant i e an atom a number or a reference var X ISO 8 3 1 The predicate succeeds when X is a variable nonvar X ISO 8 3 7 The predicate succeeds when X is not a variable i e atomic or compound
30. can be missing The property can be changed sys_private S The property indicates that the predicate or evaluable function has been marked private in source context S The property is multi valued and can be missing override S The property indicates that the predicate has been marked override in source context S The property is multi valued and can be missing The property can be changed The following operator properties for the module system are provided visible V The property indicates that the syntax operator has visibility V The argument V can have the values public and private The property is single valued and can be missing The property can be changed override The property indicates that the override warning for this operator is suppressed The property is single valued and can be missing The property can be changed The following source properties for the module system are provided sys_source_preload The property indicates that the source is preload The property is single valued and can be missing The property can be changed for user sources sys_source_visible V The property indicates that the source has default visibility V for their members The argument V can have the values public and private The property is single valued and can be missing The property can be changed for user sources February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 115 of 134 Jan Burse Language
31. class C foreign_fun l C M Succeeds with registering the predicate indicator as a foreign evaluable function that calls the method M of the class C foreign_const l C M Succeeds with registering the predicate indicator as a foreign evaluable function that gets the field M of the class C February 23 2019 jekejeke_lang_run_2019_02_01_e docx Page 103 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility Matrix The following compatibility issues persist for the system theory Table 12 Compatibility Matrix for the System Theory Nr Description System 1 N A N A February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 104 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 5 6 Bootload Package This theory is concerned with extending the Prolog system One way to extend the Prolog system is by adding foreign predicates Another way to extend the Prolog system is by add ing a capability Interpreter State Some interpreter state can be queried and updated Capability Plug Ins Capabilities bundle a set of predicates Prolog Texts Knowledge bases can be consulted from text sources Path Resolution Paths can be resolved against the class paths or active libraries Module System Predicates can be protected from external access Compatibility Matrix ISO DEC10 compatibility issues of the administration theory February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 105 of 134
32. comparison The type of the return value depends on the order of the arguments of these evaluable functions min max integer x integer gt integer meone Meose sell erc x Gloar gt selloaic min max decimal x decimal gt decimal epsilon float The constant epsilon allows querying the smallest float number that when added to one will still result in a float number different from one without any rounding The following built in predicates are provided for arithmetic comparison The built ins arith metically evaluate their arguments before performing their tests X Y ISO 8 7 1 Succeeds when X arithmetically equals Y otherwise fails X Y ISO 8 7 1 Succeeds when X does not arithmetically equal Y otherwise fails X lt Y ISO 8 7 1 Succeeds when X is arithmetically less than Y otherwise fails X lt Y ISO 8 7 1 Succeeds when X is arithmetically less or equal to Y otherwise fails X gt Y ISO 8 7 1 Succeeds when X is arithmetically greater than Y otherwise fails X gt Y ISO 8 7 1 Succeeds when X is arithmetically greater or equal to Y otherwise fails The following evaluable functions are provided for arithmetic comparison min X Y TC2 9 3 9 If X and Y are both numbers then the function returns the minimum of X and Y max X Y TC2 9 3 8 If X and Y are both numbers then the function returns the maximum of X and Y epsilon N208 9 7 3 Returns the ulp of one February 23
33. evaluation_error lt msg gt java lang RuntimeException system_error lt msg gt java lang Error As is java lang Exception representation_error lt msg gt Otherwise Prolog variables and Prolog compounds New java lang Error are always passed as the Java classes TermVar and TermCompound A formal parameter or result by the Java class Object does not wrap February 23 2019 jekejeke_lang run_2019 02 01 e docx Page 102 of 134 Jan Burse Language Runtime XLOG Technologies GmbH atomics and these are passed unwrapped On the other hand a formal parameter or result by the Java class Term does wrap atomics and these are passed wrapped The distinction is important for atoms since atoms also carry call site information which can only be preserved by representing them through the Java class TermAtomic The following foreign predicate predicates are provided foreign I C M Succeeds with registering the predicate indicator as a foreign predicate that calls the method M of the class C foreign_constructor l C M Succeeds with registering the predicate indicator as a foreign predicate that calls the constructor M of the class C foreign_getter l C M Succeeds with registering the predicate indicator as a foreign predicate that gets the field M of the class C foreign_setter I C M Succeeds with registering the predicate indicator as a foreign predicate that sets the field M of the
34. find different forms of division The result type of the evaluable function integer 1 is always an integer On the other hand the result type of the evaluable functions truncate 1 floor 1 ceiling 1 and round 1 is the same as the argument type integer truncate towards zero floor towards lower infinity ceiling towards upper infinity round towards nearest neighbour or then away from zero Examples ic LOO gt SS floor 3 14 gt 4 floor 0d3 1415 gt 4 The division is based on a hypothetical operation This operation is approximate for float arguments and exact for integer and decimal arguments The result type of the evaluable functions 2 and div 2 is always an integer On the other hand the result type of the eval uable functions rem 2 and mod 2 is the same as the argument types X Y integer X F Y X div Y integer floor X F Y Xrem Y X X Y Y X mod Y X X div Y Y Examples S A 2 gt 2 5 0 7 2s gt 2 0e 0O f7 2 gt 2 B ff 2 gt 2 5 div 2 gt 3 5 ice 2 gt 1 550 sein 2 0 gt 1 0 0d5 00 rem 2 gt 0d1 00 So ree mee gt 1 5 moc 2 gt 1 If the arguments of the binary operations have different types the same widening as already defined for the basic operations is applied This means the widening is done towards the big ger domain of the two arguments The following rounding operations are recognize
35. in A with the atom for the block B Otherwise the predicate succeeds in B with the atom for the block B term_atom T A term_atom T A O The predicate succeeds when A is the serialization of the term T The ternary predicate accepts read respectively write options O The following Prolog flags for string predicates are provided max_code The legal value is an integer The value gives the maximum value of a character code Default value is Ox1O0FFFF The value cannot be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 92 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility Matrix The following compatibility issues persist for the structure theory Table 8 Compatibility Matrix for the Structure Theory Nr Description System 1 Does not have the predicates float and number DEC10 2 Does not have the predicate compound DEC10 3 Has predicate name DEC10 4 Does not have predicates atom_codes and number_codes DEC10 5 Does not have predicate unify_with_occurs_check DEC10 6 Does not have predicate copy_term DEC10 7 Has length predicate DEC10 8 Has no predicate findall 3 DEC10 9 Has mention of null atom in lexical comparison ISO 10 Has mention of collating sequence in lexical comparison ISO 11 Does not have max_code flag ISO 12 Allows blanks at the beginning of numbers ISO 13 Has classification and case conversion built ins UNID 14 Has nor
36. oy lt acseccssatnecvy cccsvaxocatncsnsccereaedcaaneevscaauesescaencavsccatesneedenesniceaueseecaaneens 97 Table 10 Parameter Type Mapping ccccceeecessccceceeeeeeeeeeeeaaeeeeeeeeeeeesenaaeaeeeeeeeeeeenesaaaaes 102 Table 11 Exception Type MappinG sicitesticcsetesai ches otic me painel yetwcneebneeaesetieeub aed eevee sees 102 Table 12 Compatibility Matrix for the System TheOFy ccceseeeeeeeeeeeeeeeenneeeeeeeeeeteeeenaaees 104 Table 13 Compatibility Matrix for the Administration Theory ccccccccccccccceeeeceeeeeeeeeeeees 117 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 133 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Acronyms DEC10 1 ISO 2 3 UNID 4 TC2 6 References 1 2 3 4 5 6 7 8 9 10 Bowen D L et al 1982 DECsystem 10 PROLOG USER S MANUAL Department of Artificial Intelligence University of Edinburgh 10 November 1982 http www cs cmu edu afs cs project ai repository ai lang prolog doc intro prolog doc ISO 1995 Prolog Part 1 General Core International Standard ISO IEC 13211 1 First Edition 1995 06 01 Richard O Keefe 2011 An Elementary Prolog Library Draft 8 November 19 2010 http www complang tuwien ac at ulrich iso prolog pllib 2010 11 19 htm Pereira F C N and Warren D H D 1980 Definite Clause Grammars for Language Analysis A Survey of the Formalism and a Comparison with Augmented Trans
37. range Examples 2009 is a number and also an integer OXER is a number and also an integer Ola is a number and also an integer SeA is a number and also a float 0da 199798 is a number and also a decimal OrA276B3 is a reference KeS N 6 is not a number float fraction missing When the number word starts with a decimal indicator Od then it is converted into a deci mal constant The conversion might fail when the number word does not conform to the deci mal syntax or when the number is outside the representation range The optional fraction and optional exponent influences the scale of the decimal number When the number word contains the period then it is converted into a float constant oth erwise it is converted into an integer constant The conversion might fail when the number word does not conform to the integer or float syntax or when the number is outside of the representation range February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 30 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Examples 2000 000 OATI PEE 3 14159 26535 89793 0b1 0 is a number and also an integer is a number and also an integer is a number and also a float is not a number two underscores in a row AP oP o o2 It is also allowed that the mantissa the fraction or the exponent contain one or many under scores This also holds if there is a radix small float or deci
38. relative source path R is loaded If the current time is after the expiration of the source then it will connect to the source If the source was not modified since its last modified then it will consult the source consult R First retract the old facts and rules of the relative source path R Then assert the new facts and rules from the relative source path R During assert also process the direc tives from the relative source path R Before assert the scope is temporarily changed to the relative source path R unload_file R Detach the source identified by the relative source path R Si weny Sml The predicate processes the path specifications Si Sm The following path specifi cations are recognized R Ensure load the relative path R R Detach the relative path R R Consult the relative path R make The predicate ensures that all used sources are loaded rebuild The predicate consults all used sources include R ISO 7 4 2 7 Doesn t retract the old facts and rules of the relative source path R Asserts the new facts and rules from the relative source path R Processes the directives from the relative source path R Doesn t change the scope to the relative source path R discontiguous l ISO 7 4 2 3 The predicate sets the predicate indicator to discontinuous multifile I ISO 7 4 2 2 The predicate sets the predicate indicator to multi file February 23 2019 jekejeke_lang_run_2019 02 _01_e docx
39. structure univ reflect pred bootload engine runtime distributed runtime distributed arithmetic elem arithmetic trigo reflect source arithmetic trigo reflect pred structure atom structure atom bootload toolkit bootload path bootload module bootload module bootload toolkit runtime quali bootload toolkit bootload toolkit bootload toolkit bootload toolkit bootload path bootload load reflect source bootload load reflect foreign reflect pred bootload load bootload module runtime meta runtime dynamic bootload toolkit runtime quali structure vars structure vars structure vars bootload toolkit bootload toolkit bootload module reflect pred reflect oper bootload path structure vars bootload load bootload toolkit bootload load bootload load Page 129 of 134 Jan Burse Language Runtime XLOG Technologies GmbH sys_show_syntax 1 bootload load sys_show_vars 0 runtime session sys_syntax_property_chk 3 bootload load sys_term_singletons 2 structure vars sys_univ 2 runtime quali sys_var 1 runtime quali tan 2 arithmetic trigo term_variables 2 structure vars term_variables 3 structure vars thread_local 1 runtime dynamic truncate 2 arithmetic round unify_with_occurs_check 2 structure univ unload_file 1 bootload load use_file_extension 1 bootload module use_module 1 bootload module use_package 1 bootload module version 0O runtime session welcome 0 runtime session xor 3 arithmetic bits Package Local Predicates
40. sys_index Xo Xj Xn when the operator sys_index is defined as postfix The postfix empty set Xo and single ton set Xo Xi expressions are parsed as dictionary terms sys_struct Xo respectively sys_struct Xo X1 when the operator sys_struct is defined as postfix Examples ol AXE 2d is an array index term poime ly Vezi 6 is an dictionary term aie Sitea is a zero argument term role A further special syntax allows zero argument terms For this purpose the compound syntax has been extended to accept an empty argument list Further the expression syntax has as well be accepted to accept a unit atom An empty argument list is not mapped to a zero argu ment compound but to a unit atom postfix expression When writing out a term canonically operator definitions are ignored an expressions are writ ten as compound During non canonical write expressions are written back as expressions Further parenthesis are put where the mix of operator level demands it Finally escaped op erators are put in parenthesis when necessary February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 40 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility The following compatibility issues persist on the term syntax level Table 3 Compatibility Matrix for the Term Syntax Nr Description System 1 Has div operator div DEC10 2 Modulo mod has different level DEC10 3 Has
41. the operator multiple times in the same expression without paren thesis The following operator icons are supported Table 9 Operator Modes Icon Type Associativity fx prefix No fy prefix Yes xt postfix No yf postfix Yes xfx infix No yfx infix Left xfy infix Right Example PS Srk OPNA O OEE ar 6 append nil X X ISENE Gre Ap R Se yeyojorsincl M0 ap Po ID z JCO V6 GROE o XES NN Y at bt 4 cttnil X attnil Y bt 4 ct 4 nil In the example above we have defined an infix operator 2 with right associativity Jeke jeke Prolog provides further properties of individual operators The access of the properties is based on an operator indicator which is one of the terms prefix O postfix O or infix O where O is the operator name The user operator indicators can be enumerated via the pred icate current_oper 1 The operator properties can be accessed and modified via the predi cates oper_property 2 set_oper_property 2 and reset_oper_property 2 oper gt Moresieae mene AA Moostcigse menie We wame ao inven WU name gt module name atom A first set of operator properties deals with the visibility of the operator These are the proper ties system O full_name 1 and private O Pretty printing is done by controlling the indentation of operators and the spaces around an operator Pretty printing is only in effect for terms aka clauses and goals Ar
42. trigo reflect pred bootload module runtime session bootload module bootload load bootload module Page 128 of 134 Jan Burse reference 1 rem 3 repeat 0 reset_atom_property 3 reset_oper_property 2 retract 1 retractall 1 round 2 set_arg 4 set_atom_property 3 set_prolog_flag 2 setup_balance 1 setup_balance 2 sign 2 sin 2 source_property 2 sqrt 2 static 1 sub_atom 4 sub_atom 5 sys_activate_capability 2 sys_add_path 1 sys_add_resource 1 sys_auto_load 1 sys_calc_install_id 2 sys_callable 1 sys_capability_property 2 sys_check_license 1 sys_check_licenses 0 sys_current_capability 1 sys_current_path 1 sys_current_provable 1 sys_current_source_site 2 sys_current_syntax 1 sys_declaration_indicator 2 sys_declaration_indicator 2 sys_declaration_indicator 2 sys_declaration_indicator 2 sys_declaration_indicator 2 sys_declaration_indicator 2 sys_finit_capability 1 sys_functor 3 sys_get_variable_names 1 sys_goal_globals 2 sys_goal_kernel 2 sys_init_capability 1 sys_init_capability 2 sys_load_resource 1 sys_make_indicator 3 sysS_make_oper 3 sys_module_site 2 sys _number_variables 4 sys_provable_property_chk 3 sys_reg_license_text 2 sys_show_base 1 sys_show_provable_source 2 February 23 2019 Language Runtime jekejeke_lang_run_2019 02 _01_e docx XLOG Technologies GmbH structure type arithmetic round runtime logic reflect pred reflect oper runtime dynamic runtime dynamic arithmetic round
43. unifies with F Ai An functor X N A ISO 8 5 1 If X is atomic then the predicate succeeds when N unifies with X and A unifies with 0 If X is the compound F Ai An then the predicate succeeds when N unifies with F and A unifies with n If N is atomic and A is 0 then the predicate succeeds when Y unifies with N If Nis an atom A is an integer n21 and Ai An are fresh arguments then the predicate succeeds when Y unifies with N Aij An arg K X Y ISO 8 5 2 If K is a positive integer in the range of an arity and X is a callable f Aj An then the predicate succeeds when 1 lt k lt n and Ax unifies with Y set_arg K X Y Z If K is a positive integer in the range of an arity and X is a callable f Aj An then the predicate succeeds when 1 lt k lt n and Z unifies with f A1 Ax 1 Y Akt An X Y ISO 8 2 1 The predicate succeeds when X and Y unify no occurs check is performed unify_with_occurs_check X Y ISO 8 2 2 The predicate succeeds when X and Y unify occurs check is performed X Y ISO 8 2 3 The predicate succeeds when X and Y do not unify no occurs check is performed The following Prolog flags for term building and unification are provided max_arity ISO 7 11 2 3 The legal value is an integer The value gives the maximum number of arguments in a compound Default value is 2147483647 The value cannot be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx P
44. 2 3 and absolute_resource_name 1 provide file name resolving The predicate absolute_file_name 2 works bi directionally For a given already re solved path it will make a best effort attempt to reconstruct either a compound form foreign 1 library 1 or verbatim 1 or a relative path The following path resolution predicates are provided sys_add_path R The predicate succeeds in adding the relative path R to the current class loader sys_current_path A The predicate succeeds in A with the currently added absolute paths A along the class loaders February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 112 of 134 Jan Burse Language Runtime XLOG Technologies GmbH sys_add_file_extension E The predicate succeeds in adding the file extension database entry E to the current knowledge base The following database entries are recognized text lt name suffix gt lt mime type gt Library file binary lt name suffix gt lt mime type gt Foreign file resource lt name suffix gt lt mime type gt Resource file sys_remove_file_extension E The predicate succeeds in removing file extension database entry with the name suf fix E from the current knowledge base sys_current_file_extension E The predicate succeeds in E with the currently added file extension database entries along the knowledge bases absolute_file_name R A absolute_file_name R A O The binary predicate succeeds when the read path R resolv
45. 2019 jekejeke_lang_run_2019 02 _01_e docx Page 83 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility Matrix The following compatibility issues persist for the arithmetic theory Table 7 Compatibility Matrix for the Arithmetic Theory Nr Description System 1 Has only integer operations DEC10 2 Has 18 bit masking short hands DEC10 3 Has ASCII value operator DEC10 4 Does not have decimals ISO 5 Does not require widening ISO 6 Does not require narrowing ISO February 23 2019 jekejeke_lang_run_2019_02_01_e docx Page 84 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 5 4 Structure Package This theory is concerned with the underlying term model of the Prolog interpreter We find the following topics Type Testing Testing the type of terms Term Variables Determining the variables of terms Lexical Comparison Lexically comparing terms Building Unification Constructing and deconstructing terms String Predicates Some predicates that deal with chars and codes Compatibility Matrix ISO DEC10 compatibility issues of the structure theory February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 85 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Type Testing Type testing allows checking terms for their type without an attempt to instantiate These predicates are therefore meta logical The basic data types of the ISO Prolog core standard
46. For the money example there are the following sources e money p The Prolog text to solve the letter puzzle Prolog Text money Prolog code for the backtracking example Puzzle originally published July 1924 issue of Strand Magazine by Henry Dudeney Copyright 2012 XLOG Technologies GmbH Switzerland Jekejeke Prolog 0 9 4 a fast and small prolog interpreter F F F HF F SS oneof List Elem List omeo DKS kp YO o Gneo DX Ye AWS s oneone 4 Wy o assign List List assaem I Jo asstat AN Ih g Onei 8 IN BSSaubeiit I gt Q puzzle List Puzle OA g EEN assign X M 0 s 0 OO ORS LOORI e LOAN F OOO MAES 1000 LOR NEO OOM 100070 m LOON i LOE q i K FU February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 120 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 6 4 Rabbits Example For the rabbits example there are the following sources e cage p The Prolog text for the cage e nest p The Prolog text for the nest Prolog Text cage Prolog code for the module mutual recursion example Growth of an idealized rabbit population according to Liber Abaci from 1202 by Leonardo of Pisa known as Fibonacci Copyright 2014 XLOG Technologies GmbH Switzerland Jekejeke Prolog 1 0 1 a fast and small prolog interpreter Meo eo Se RS ye eo ee Be eS ae Ss module cage adu
47. Gb alah ale Sakae abel Ne ere ein sly tae A ESN It is now simple to put the last pieces together We can define a predicate primes which gen erate the initial list and then sift through it primes High R integers 2 High L Sale Ij Tella IR We are now done with our implementation and can invoke the predicate for bigger upper bounds than only m 16 primes 16 X Noe Bie o The Aik bse primes 100 X 2 3 5 7 dil 1s 27 1S 2s 29 Si S37 Al 423 47 53 59 Gil Gi Tiy Wr T9 SS 89 97 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 11 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 2 3 Money Example ISO The Jekejeke Prolog programming language provides the usual backtracking The given ex ample shows the solving of a small letter puzzle The problem consists of finding distinct dig its for the letters below so that they fit the below addition S N D an Ml 0 IR 1g Mt O AN ty 36 pa Many puzzles are formulated in a similar fashion i e to find an exemplar from a collection that satisfies a certain condition This leads to the programming pattern of generate and test The pattern consists of defining goals Gi Gn that enumerate the exemplars of the collec tion and of defining goals T1 Tm that verify the condition The problem is then solved by the following query Gi 3 oe Gio Bil
48. Is a non data input abc Is neither a data nor a non data input oe Is neither a data nor a non data input We might find a non data line at the end of a Prolog text Omitting the terminating period from a data line is considered an error Similarly adding a terminating period to a non data line is as well considered an error Block comments are only detected when they are not pre ceded by a graphic character February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 32 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Unicode Extension The ISO core standard allows extending the set of character codes beyond what is defined in its documentation Jekejeke Prolog supports the Unicode character set as its processor ex tension The particular Unicode version that is supported depends on the underlying Java vir tual machine The following definitions replace the corresponding definitions in the previous sections We indicate a replaced non terminal by appending a single quote The Unicode character types are denoted by all upper case What concerns fillers we did neither touch the line comments the block comments nor the end of line character But we extended the class of layout characters slightly Including the FORMAT Unicode character type caters for covering the byte order mark BOM xFEFF Further including the CONTROL Unicode character type caters for covering ASCII control characters We have exclu
49. JVM known to the interpreter The predicate thread_statistics 3 returns some key figures concerning the given thread whereas the predicate threads O displays the key figures for all known threads on the standard output Example threads TE Alive Clauses 21 Yes 0 25 Yes Lp 256 SOG The JVM will notify the Prolog interpreter about low memory On the Android platform this is a suicide notice since foreground heap compaction is not yet available and it is therefore recommended to exit the Prolog interpreter On both the Swing and the Android platforms the thread statistics are then used to decide which thread will be aborted The following stats predicates are provided statistics The predicate displays the current statistics key value pairs statistics K V The predicate succeeds for the values V of the keys K The following keys are re turned by the predicate max The maximum memory in bytes used The currently used memory in bytes free The currently allocated but unused memory in bytes uptime The time since start up in milliseconds gctime The time spent for garbage collection in milliseconds time The time spent by this Jekejeke Prolog thread wall The current time in milliseconds time A The predicate succeeds whenever the goal A succeeds The predicate will measure the time for the execution of the goal A irrespective of whether the goal A succeeds or fails Redoing the goal A is measured when the
50. Jekejeke Runtime Reference Version 1 3 5 February 01 2019 XLOG Technologies GmbH Jan Burse Language Runtime XLOG Technologies GmbH Jekejeke Prolog Runtime Library 1 3 5 Language Reference Author XLOG Technologies GmbH Jan Burse Freischutzgasse 14 8004 Zurich Switzerland Date February 01 2019 Version 0 68 Warranty amp Liability To the extent permitted by applicable law and unless explicitly otherwise agreed upon XLOG Technologies GmbH makes no warranties regarding the provided information XLOG Tech nologies GmbH assumes no liability that any problems might be solved with the information provided by XLOG Technologies GmbH Rights amp License All industrial property rights regarding the information copyright and patent rights in particu lar are the sole property of XLOG Technologies GmbH If the company was not the origina tor of some excerpts XLOG Technologies GmbH has at least obtained the right to repro duce change and translate the information Reproduction is restricted to the whole unaltered document Reproduction of the information is only allowed for non commercial uses Small excerpts can be used if properly cited Cita tions must at least include the document title the product family the product version the company the date and the page Example Defined predicates with arity gt 0 both static and dynamic are indexed on the functor of their first argument 1 p 17
51. PUNCTUATION OTHE RE PUNCTUATION except W 7 i A wow P AEN U MATH SYMBOL except CURRENCY SYMBOL MODIFIER SYMBOL except OTHER SYMBOL except xFFFD Examples lt gt 22 amp S s The name lt gt 2 amp S 2 tax gt ihe number 27 che mame SS and the mame Stax ESA S e mans Y JE alk Y HE E 2 mie nemas VEY a ane V When writing out Prolog terms spaces are automatically put around operators Also names are quoted when necessary Additionally the character codes inside quoted names are auto matically escaped The current rule is that all characters belonging to the layout character class except for the space itself are escaped Escaping produces a control character an octal code or a hex code Hex coding is used for character codes above or equal 512 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 35 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility Matrix The following compatibility issues persist on the token level Table 2 Compatibility Matrix for the Token Syntax Nr Description System 1 Negative numbers are recognized as tokens DEC10 1 2 Integer numbers are bounded DEC10 3 Has as synonym for the braces DEC10 4 Has as synonym for the vertical bar in lists DEC10 5 Has as synony
52. Page 109 of 134 Jan Burse Language Runtime XLOG Technologies GmbH listing The predicate lists the user clauses of the user syntax operators evaluable functions and predicates Only non automatic evaluable functions and predicates are listed listing I The predicate lists the user clauses of the user syntax operators evaluable functions and predicates that match the pattern Only non automatic evaluable functions and predicates are listed The following Prolog flags for theory files are provided sys_last_pred The value is a predicate indicator or null The value indicates the head predicate of the recently consulted clause The value can be changed sys_timeout The value is a positive 64 bit integer The value determines the wait before source locks timeout during loading The value is measured in milliseconds The value can be changed verbose The value can be one of the atoms off summary details or on The value indicates the verbosity level for the loading and unloading of files The summary level shows a count of the loaded and unloaded files The details level shows each loaded or un loaded file names The on level shows both details followed by summary The following predicate properties for theory files are provided sys_usage S The property indicates that the defined predicate has definitions in the source context S The property is multi valued or can be missing The property cannot directly be changed dis
53. Predicate Module sys_load_file 2 bootload load sys_register_file 1 bootload load Non Private Meta Predicates Predicate Exp Body Rule Module 0 gt 0 yes yes no runtime logic 0 0 yes yes no runtime logic 0 gt 0 yes yes no runtime logic 2 0 yes no no runtime quali 0 0 yes yes no runtime logic 0 yes no no runtime logic asserta 1 yes no no runtime dynamic assertz 1 yes no no runtime dynamic balance 0 yes no no runtime distributed balance 0 yes no no runtime distributed call 0 yes no no runtime logic clause 1 0 no no no runtime dynamic horde 0 yes no no runtime distributed horde 0 yes no no runtime distributed once 0 yes no no runtime logic retract 1 no no no runtime dynamic retractall 1 no no no runtime dynamic setup_balance 0 yes no no runtime distributed setup_balance 0 yes no no runtime distributed Non Private Closure Predicates Predicate Module February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 130 of 134 Jan Burse S IN Pan aT A i o o gt He SS Bees ao E pa lt lt 1 gra VV Iii tw A bt ee ey py Oe a a eS e sk kkk ke oho te W Y YY s lt gt H D Non Private Syntax Operators Level Mode Operator 1200 fx 1150 fx thread_local 1150 fy override 1150 fy public 1150 fx meta_predicate 1150 fx meta_function 1150 fx dynamic 1150 fy discontiguous 1150 fy multifile 1150 fy private
54. Runtime XLOG Technologies GmbH Bitwise Operations We provide bitwise operations defined on integers They are not defined for floats or deci mals The bitwise operations work for negative and positive integers including zero They also work for unbounded integers The bit pattern that corresponds to an integer can be viewed as infinitely extending to the left for positive integers and zero by 0 s and for negative integers by 1 s The bitwise operations then work on the corresponding binary digits Examples i E lOO a e OIC 11 2 sos 9 gk Oia i 11 f 2 gt jae i 11 gt gt 2 gt 3 LO GI eee e a 1010100 Sin iQ OO The displacements n in the shift operations are restricted to the range 2147483648 lt n lt 2147483647 When the displacement is outside this range an exception is thrown A nega tive displacement shifts in the opposite direction The following bitwise operations are recognized in evaluations X ISO 9 4 5 If X is an integer then returns the bitwise complement of X X A Y ISO 9 4 3 lf X and Y are both integers then the function returns the bitwise X and Y X VY ISO 9 4 4 If X and Y are both integers then the function returns the bitwise X or Y xor X Y TC2 9 4 6 If X and Y are both integers then the function returns the bitwise exclusive X or Y X lt lt Y ISO 9 4 2 If X and Y are both integers then the function returns X shifted by Y places left
55. Syxrscabicaeie2 WJA meta _specifier3 mera _specifier2 gt integer WSs 7 mera SPECTET WE meta_specifier3 eege Example f mere Precil eare Comins gt 2 o A positive integer n indicates a goal and a negative integer n indicates a clause If the integer n respectively n 1 if n lt 0 is different from zero then the argument is a goal closure respec tively clause closure The question mark indicates that the argument is neither a goal nor a clause The 1 wrapper indicates that the argument is also an object message It should be noted that Jekejeke Prolog executes meta predicates even when meta predicate directives are not present The meta predicate directives are needed for pretty printing and term expansion Closures are not supported during term expansion Term expansion for clauses can be switched on off by the sys_clause_expand flag and it is on by default The hash tag indicates that the argument is an evaluable expression Space newline and indent insertion will be suppressed during pretty printing Evaluable functions don t need spe cial meta predicate declarations Meta predicate declarations are assumed so that the whole evaluable expression is cross referenced The following meta predicate predicates are provided meta_predicate M The predicate sets the corresponding functor to meta predicate declaration M meta_function M The predicate sets the correspond
56. _lang_run_2019 02 _01_e docx See the body conversion section See the body conversion section See the predicate definitions section See the logical predicates section See the predicate definitions section See the predicate definitions section See the predicate definitions section See the prolog texts section See the prolog texts section See the prolog texts section See the prolog texts section See the module system section See the module system section See the module system section See the meta predicates section See the meta predicates section See the meta predicates section See the meta predicates section See the dynamic database section See the dynamic database section See the dynamic database section See the dynamic database section See the dynamic database section See the dynamic database section See the special predicates section See the special predicates section Page 47 of 134 Jan Burse Source Properties Language Runtime XLOG Technologies GmbH Source properties can be accessed via the system predicates source_property 2 set_source_property 2 and reset_source_property 2 The following source properties are supported by the Jekejeke Prolog runtime library sys_notrace sys_capability last_modified version_tag See the source files section expiration See the source files section date See the source files section max_age See the source files section short_name See th
57. a Prolog text The Prolog text will consists of facts about a particular animal and rules about animals in general After reading the Prolog text by the Prolog system it will be possi ble to pose a query to the Prolog system and guess the type of an animal The Prolog text starts with the facts To guess another animal these facts have to be changed and the Prolog text has to be re read by the Prolog system A Prolog fact consists of a predicate name followed by a number of arguments For our example we will only make use of predicates with a single argument that is an atom but in general predicate can have more arguments and their argument types can differ from an atom motion walk ECES The Prolog text then continues with the rules This order is not mandatory for a Prolog text since rules can have references to predicates either occurring before or after the rule itself A Prolog rule makes use of the turnstile operator 2 This operator will separate the head of the rule from the body of the rule The body itself will make use of the comma operator 2 This operator will separate the goals in the body of the rule class mamal motion walk skin fur HECHE animal rodent class mamal diet plant ERCE The Prolog text is found in the support zip under the file name animals p The Prolog text can be read in for the first time or re read a second time by the consult command The con sult comma
58. ach picked number will be a prime number The process stops when no more prime numbers are left Of course we can also already stop crossing out a little bit earlier namely when we find a prime number p such that p p gt m 3 5 7 9 11 13 15 5 7 11 13 From the above sieve we can read off that 2 3 5 7 11 and 13 are the only prime numbers between 2 and 16 We will now go on and implement this sieve in Prolog We use Prolog lists to represent the sieve The list will only contain the uncrossed numbers The first predicate that we need is the predicate that builds the initial list integers Low High Low Rest Low lt High Mis Low 1 integers M High Rest integers _ II The first rule first checks whether we are still inside the lower and upper bound If yes we re turn the lower bound as the first list element and recursively call the predicate with an in creased lower bound Otherwise we return an empty list We can test it for m 16 integers 2 16 X x 2 Se e Be Gr Te Be SG 10 Ti 12 13 14 15 16 As a next step we need a predicate that is able to cross out multiples of a given number This predicate will input the sieve before crossing out multiples and the output the sieve after crossing out the sieve To check multiplicity we use the arithmetic remainder function remove _ PeEMoOWve IE LSi RP INS S Tirem 2 SoS oO I remove Is P Nis
59. ack trace is determined and a corre sponding InterpreterException is thrown A couple of Java exceptions are recognized and wrapped into Prolog errors before throwing The family of interrupt exceptions is mapped to the signal currently stored in the interpreter and the signal is cleared Table 11 Exception Type Mapping Java Class Jekejeke Prolog Error jekpro tools call InteroreterException As is jekpro tools call InterpreterMessage As is plus stack trace jekpro tools term RuntimeWrap Mapping of the lt cause gt java net SocketTimeoutException resource_error socket_timeout java io InterruptedlOException lt signal gt java nio channels FileLockinterruptionException lt signal gt java nio channels ClosedByInterruptException lt signal gt java io UnsupportedEncodingException existence_error encoding lt msg gt java net MalformedURLException syntax_error malformed_url java util zip ZipException resource_error corrupt_archive java nio charset CharacterCodingException syntax_error malformed_path java io FileNotFoundException existence_error source_sink lt msg gt java net UnknownHostException existence_error host lt msg gt java net SocketException existence_error port lt msg gt java io IOException resource_error io_exception java lang InterruptedException lt signal gt java lang ArithmeticException
60. age 90 of 134 Jan Burse Language Runtime XLOG Technologies GmbH String Predicates Characters and codes are not genuine data types in Jekejeke Prolog Characters are simply atoms of code length one and codes are integer values in the range 0 to Ox10FFFF Atoms are internally represented as sequences of 16 bit words Codes in the range above 16 bit are represented as surrogate pairs It is permitted to have single standing surrogates in an atom It is also permitted to have surrogates in escape sequences Examples char code xDBFF xDFFF X XA Ro Char Cocks lt 7 LIAL o KE RANO EN char code xl0FFFF X X ALLL Besides the ISO core standard inspired atom related predicates we also provide Prolog com mons inspired atom related predicates The predicate atom_split 3 allows concatenating and splitting atom lists to and from atoms The predicate atom_number 2 allows converting be tween atoms and numbers Examples Z arom syle Os V Vp apog el s 26 fl I R atom sjollakic a o Cp 4 vy Xo X a b c The arguments of the below string predicates do not work with 16 bit word units The argu ments are measured in code units This results in a certain performance penalty For exam ple the length of an atom is not anymore a one shot operation but instead the whole atom has to be scanned to compute the length Similar conversions apply to offsets The following string predicates are provided
61. and the period can also be used as an infix or postfix operator without quoting them Whether a certain atom or operator can be used fur ther depends on the built in op 3 which might refuse certain definitions Examples 8 is a prefix expression corresponds to 5 5 6 6 is an infix expression corresponds to 5 6 5 days is a postfix expression corresponds to days 5 assertz p q is a compound mode 6 is a compound The parenthesis serves to circumvent the level rule of the operators Arguments from compounds and lists have the level 999 To use higher level operators as arguments we therefore have to put them in parenthesis The operator detection itself can be escaped when the operator directly precedes a stop character February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 39 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Special Syntax We provide some syntax extensions in the spirit of SWI Prolog 7 10 To allow a richer syn tax we additionally allow closed lists singleton sets and unit atoms as operators thus provid ing additional parameters when forming a term The resulting special syntax provides con venience for array subscripts tagged structures and zero arguments operator eCo PA Saroume nts SA Pate eeu GEA Ew A a Nee wow wom a A postfix list Xo X1 Xn expression is parsed as an array index term
62. and the rest The rest cannot be used as a name or a variable in a Prolog text The accepted word syntax depends on the character set extension By default Jekejeke Prolog provides a Unicode character set extension which is documented in a later section name gt celica exosoi M N MIN wri w W wow T L T L L lower alpha digit Egraphte Eoropie ECEPTE er strige variable gt upperscore alpha digit there Toyevere Examples ol A word but not a name and not a variable The name The name o2 ol foobar The name foobar Veneto Satin z MiS meme Yare Sihat X12 3 he variable IXIA Col T a Pas wyweheseloike Vool T Words that start with an upper case letter or with the underscore _ are considered as vari ables Back quoted strings also belong to the category of variables they allow for arbitrary character sequences used as variables Words that start with a lower case letter or a graphic character are considered as names Finally single quoted strings also belong to the category of names similarly they allow for arbitrary character sequences used as names February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 29 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Number Syntax When the number word starts with a radix indicator then after the radix indicator an integer number in the corresp
63. are provided sys_alias A The syntax operator property indicates that the operator should be replaced by A dur ing parsing The property is single valued or can be missing The property can be changed sys_portray P The syntax operator property indicates that the operator should be replaced by P dur ing un parsing The property is single valued or can be missing The property can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 98 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Source Files The Prolog system maintains a table of consulted source files in each knowledge base The entries in this table have a longer life cycle than the entries in the stream alias table When a named stream is closed the alias is removed from the alias table and thus the stream properties are not anymore accessible via the alias On the other hand when a source file is closed after consult the entry in the source file table is not removed For a verbose consult ensure loaded or unload the source also keeps a property with the timing of the operation The timing is suspended when a source consults or ensure loads another source so that the property only shows the time spent in the given source Further a source records the other sources that this source has been consulted or ensure loaded This way a graph of the sources and their dependency is built Each source has an individual lock This lock serializes the pred
64. at are usually defined for the interpreter e Arithmetic Package The modules concerned with the numbers of the interpreter e Structure Package The modules concerned with the term model of the interpreter e Reflect Package The modules concerned with accessing the interpreter e Bootload Package The modules concerned with extending the interpreter February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 50 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 5 1 Kernel Package This theory groups the minimal set of predicates that need to be predefined by the interpreter itself e Special Predicates The interface of special built ins is currently not published e Body Conversion Naked goals in bodies and rules are automatically wrapped e Control Predicates The core predicates of the interpreter e Optimization Techniques Optimization techniques speed up predicate execution e Clause Indexing Clause indexing also speeds up predicate execution e Module Statistics This module provides some execution statistics e Compatibility Matrix ISO DEC10 compatibility issues of the kernel theory February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 51 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Special Predicates It is possible to register predicates and evaluable functions as special built ins via the built in special 3 A predicate indicator the service class and the service number has to be sp
65. at pass as the first argument the receiver object The directive virtual 1 can be used to set the virtual property of a predicate The following special predicate predicates are provided special C K Succeeds with registering the predicate indicator as a special builtin that calls an instance of the service class C with function index K virtual P The predicate sets the predicate P to virtual February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 52 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The following predicate properties for special predicates are provided virtual The property indicates that the predicate has the virtual property The property can be missing The property can be modified for clause defined predicates The property cannot be modified for special or foreign predicates sys_arithmetic The service class implements the predicate via the internal evaluable functions API The property can be missing The property cannot be modified February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 53 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Body Conversion Body conversion converts a goal of the form X where X is a variable into a goal of the form call X And goals which are not of the form X where X is a callable are rejected by this con version Body conversion is in effect when clauses are asserted either dynamically or stati cally The effect can b
66. ay gt package atom MuU array Behse atom package gt package atom atom The name of a predicate is qualified when it starts with a module name separated by the co lon operator Unqualified predicate names are extended by the module name of the Prolog text if the Prolog text has been elevated to a module or by the module names of correspond ing public or package local predicates found in dependent modules Examples Callele alk 2 basic lists member 2 ol is a predicate indicator is a predicate indicator is a predicate indicator ol foe A non dynamic predicate without clauses can be declared via the directive static 1 The con text of a clause is determined from the predicate name atom of the clause head The predicate current_predicate 1 succeeds for a predicate that is visible in the current con text The different visibility parameters are documented in the module system section Prop erties of a predicate can be accessed and modified by the predicates predicate_property 2 set_predicate_property 2 and reset_predicate_property 3 The following predicate definition predicates are provided static P The predicate sets the predicate P to static current_predicate P ISO 8 8 2 The predicate succeeds for the visible predicates P predicate_property P Q The predicate succeeds for the properties Q of the predicate P set_predicate_property P Q The predicate ass
67. c clause indexing But addition ally the system considers constraints such as bindings in the body of each clause Currently we do not incorporate bindings into our index The Ciao Prolog system 8 section 88 allows declaring multi argument indexes In the declaration one can specify the key type It is possi ble to index argument either on the functor or on the full term Currently we do not support indexes based on full terms The following Prolog flags for the clause indexing are provided sys_clause_index Legal values are on and off The flag indicates whether clause indexing is enabled for the knowledge base Default value is on Value can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 60 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Module Statistics This module provides some execution statistics The predicate statistics 2 returns some key figures of the memory management and the runtime system whereas the predicate statis tics O displays the key figures on the standard output The measurement of the time perfor mance of a goal is facilitated by the predicate time 1 Example 2o GEVEG LES Max Memory 512 753 664 Bytes Used Memory 68 568 872 Bytes Free Memory 444 184 792 Bytes Uptime SrA MERS GC Time LA MEIS Thread Cpu Time 1O00 Mais Current Time O2 Lai is Ise 20 3 Oe Since Jekejeke Prolog is a multi threaded interpreter we also provide statistics for the threads in
68. ch on multiple CPUs Usually setting up a parallel solu tion involves using the modules thread pipe and group The predicate balance 1 2 from the module distributed abstracts away all these details The predicate balance 1 implements a non deterministic distributed generate and test The predicate balance 2 allows additionally specifying the number of desired threads Using a modern microprocessor with a modern operating system multiple threads will run truly paral lel on multiple cores The only bottleneck being the shared memory time balance between 1 10000 X perfect X fail true Up 1 5687 me CC 14 me Thread Cou 0 me Currane 02 01 19 15 4045 Yes time balance between 1 20000 X perfect X fail true Up 6 800 ms GC 57 ms Thread Cpu 0 ms Current 02 01 19 15 45 34 Yes In the above query we used the predicate balance 1 without specifying the number of de sired threads The predicate will then use the number of logical CPUs of the main board When using the predicate balance 1 also some new overhead will be inducted by the setup and teardown of the threads and the communication between threads Parallel Search Speedup 60 0 40 0 20 0 non Android Android 0 0 Figure Measurements on a Lenovo Ideapad and on a Huawei Media Pad The predicate balance 1 is both available on the non Android and Android platform On both platforms the modules thread and group wer
69. changed short_name S The property indicates that the source has the short name S The property cannot be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 100 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Foreign Predicates Foreign predicates can be defined by Java methods constructors and fields Foreign predi cates will have retrieved the actual goal arguments by the interpreter and automatically passed to the associated Java method constructor or field More details about foreign predi cates can be found in the Jekejeke Prolog Programming Interface documentation Foreign predicates can be registered by one of the directives foreign 3 foreign_constructor 3 foreign_setter 3 and foreign_getter 3 Foreign evaluable functions can be registered by one of the directives foreign_function 3 or foreign_constant 3 The directives take as arguments a predicate specification a declaring class specification and a method constructor or field specification We can describe the arguments via the following syntax ChinceSC iminie F WEOE shavchioencers YW V OCS WV oel tS 7 rorem ConeTr tcron X stiavchiceicore 7 unoxchbils t i giemerurge w Wir seeakepar sste alinchieenceie 7 mevle 47 aron 7 rorem Gerren alinshheerceene 7 mechs 17 07 aron ya l Arora UNY aslinchiceteoie Hw moctla 7 giemeartre Wye Wiroiesikein Comsic E aliachiceicere Ww miele Ww aromi Aig Sakepiencwhes gt arom
70. contiguous S The property indicates that the predicate has been marked discontinuous in the source context S The property is multi valued and can be missing multifile The property indicates that predicate is multi file sys_multifile S The property indicates that the predicate has been marked multi file in source context S The property is multi valued and can be missing The property can be changed The following syntax operator properties for theory files are provided sys_usage S The syntax operator property indicates that the defined operator has definitions in the source context S The property is single valued or can be missing The property cannot directly be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 110 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The following theory files operators are provided H B The construct defines a Prolog rule with head H and body B February 23 2019 jekejeke_lang_run_2019_02_01_e docx Page 111 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Path Resolution A relative path that is not wrapped into a compound is resolved against the current base in write or append mode The current base is the Prolog flag base_url Otherwise in read mode if the call site is not user it is resolved against the path of the call site itself In both cases the suffixes of the sys_add_file_extension 1 command are used Example absol
71. d B are cut transparent A gt B ISO 7 8 7 The predicate succeeds when A succeeds and then whenever B succeeds Only the goal argument B is cut transparent A gt B The predicate succeeds whenever A and B succeed Only the goal argument B is cut transparent A gt B C ISO 7 8 8 The predicate succeeds when A succeeds and then whenever B succeeds or else whenever C succeeds Only the goal arguments B and C are cut transparent A gt B C The predicate succeeds whenever A and B succeed or else if B didn t succeed whenever C succeeds Only the goal arguments B and C are cut transparent repeat ISO 8 15 3 The predicate succeeds repeatedly The following predicate properties for logical predicates are provided sys_nobarrier The property indicates that the predicate is defined and cut transparent The property can be changed for defined user predicates February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 69 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Work Distribution This module provides meta predicates to distribute work over multiple threads The simplest meta predicate horde 1 2 collects the results of the spawned threads and leaves the work distribution to the spawned threads itself The other predicates distribute work items among the spawned threads but do this only on a local scale Example balance between 1 10 X Y is X X xX 1 Va Se La YG a Shy Wa
72. d in evaluations integer X If X is a number the returns the integer of X truncate X ISO 9 1 7 If X is a number then returns the rounding of X towards zero floor X ISO 9 1 7 If X is a number then returns the rounding of X towards negative infinity ceiling X ISO 9 1 7 If X is a number then returns the rounding of X towards positive infinity round X ISO 9 1 7 If X is a number then returns the rounding of X towards the nearest integer If the ab solute fraction of the number is 0 5 then returns the rounding away from zero February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 79 of 134 Jan Burse Language Runtime XLOG Technologies GmbH X Y ISO 9 1 7 If X and Y are both numbers then the function returns the truncated division of X by Y X rem Y ISO 9 1 7 If X and Y are both numbers then the function returns the remainder of X by Y X div Y TC2 9 1 3 If X and Y are both numbers then the function returns the floored division of X by Y X mod Y ISO 9 1 7 If X and Y are both numbers then the function returns the modulus of X by Y The following Prolog flags for rounding operations are provided integer_rounding_function ISO 7 11 1 4 Legal values are down ISO and toward_zero ISO The flag indicates how the 2 and rem 2 are performed Default value is toward_zero The value cannot be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 80 of 134 Jan Burse Language
73. d postfix operator issues error ISO 19 Not defined that abolish 1 could remove built ins ISO 20 Does not have a static directive ISO 21 Does not have a thread local predicates ISO 22 Does not have absolute_file_name 2 3 predicates ISO February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 74 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 5 3 Arithmetic Package This theory is concerned with the integers and floats of the Prolog interpreter We find the fol lowing topics Arithmetic Domains The used number representation Elementary Operations The available elementary operations Rounding Operations The available rounding operations Bitwise Operations The available bitwise operations Trigonometric Operations The available trigonometric operations Arithmetic Comparisons The available number comparisons Compatibility Matrix SO DEC10 compatibility issues of the arithmetic theory February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 75 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Arithmetic Domains The Jekejeke Prolog interpreter accepts numbers and internally represents them as integers floats or decimals The implementation represents floats and decimals as pairs of a mantissa and a scale For floats the scale is binary for decimals the scale is decimal float mantissa 2sce decimal mantissa 10 Examples LO 100 0m 2 OCO OL O chee 2 OCZS
74. ded the non joiner x200C and the joiner x200D hints from layout so that they can be later used in lower layout gt SPACE SEPARATOR LINE SEPARATOR PARAGRAPH SEPARATOR CONTROL FORMAT except x200C x200D Examples lt BOM gt a UNS mene UBS The definition of strings has received a slight change We introduced a new character class invalid This character class includes the character types UNASSIGNED PRIVATE_USE and SURROGATE We do also consider the replacement character xFFFD as an invalid Unicode character This character usually indicates an invalid byte sequence which could not be converted back to a Unicode sequence during stream read invalid gt UNASSIGNED PRIVATE USE SURROGATE xXFFFD Examples xFFFD The name xFFFD an invalid character xD800 The name xD800 a low surrogate When reading a term the string definition applies in its original form to the tokenization phase During parsing strings undergo an additional validation step where strings with invalid characters are sorted out If needed invalid characters can nevertheless be included in a string by using the backslash to escape the code Escaping can also be used to include single standing surrogates in strings With respect to the delimiters we added all Unicode punctuation character types that corre s
75. definite clause grammars where it then directly denotes a se quence of character terminals Instead of a double quoted string also other strings can be used as a short hand there are Prolog flags that control the default behaviour and there are Prolog options that control the behaviour of the read and write predicates February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 38 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Expression Syntax The expressions that can be formed depend on the operators and their levels that have been defined as follows The system can distinguish prefix infix and postfix operators The argu ments of an operator have to be on a lower or equal level than the operator itself so that parsing is successful The exact operator type further determines the acceptability and asso ciativity of the operator expression M gt term 1200 M 0 WwW a W op1 M x term M 1 op1l M fy term M term M 1 op2 M xfx term M 1 term M 1 op2 M xfy term M term M op2 M yfx term M 1 term M 1 op2 M XE term M op2 M yf op1 M I ae ee OM A Ginem C EO o op2 M I gt ORS aeons 1 Cuirent CSM O Po Names either quoted or unquoted can be used as operators Since the empty set and the empty list do belong to the category of atoms they can be used as an operator as well Ad ditionally the comma the vertical bar
76. dicate properties for the optimization techniques are provided sys_nobody The property indicates that the clauses of the predicate should not have body variable elimination optimization in place The value can be changed sys_nostack The property indicates that the clauses of the predicate should not have stack frame elimination optimization in place The value can be changed sys_nohead The property indicates that the clauses of the predicate should not have head variable elimination optimization in place The value can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 59 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Clause Indexing The Jekejeke Prolog system is capable of dynamically creating indexes for multiple argument positions and that might span multiple arguments Naively scanning the full clause set of a defined predicate would be inefficient Therefore when a defined predicates is invoked an analysis of the arguments of the calling goal is performed 1 First Argument Indexing When the defined predicate is called with a non variable first argument then the functor of this argument is used in a hash table lookup to find a smaller set of clauses for scanning 2 Non First Argument Indexing If the first argument is a variable then the calling goal is searched for another argument which is non variable and the functor of this argu ment is then picked for a hash table lookup 3 Multi Ar
77. e implemented via the platform Java thread and thread groups On the other hand the module pipe uses some custom Queues imple mented with the platform Java monitors February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 16 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 2 6 Pound Example In this example we demonstrate object oriented programming Object oriented programming has to be distinguished from object oriented modelling In object oriented programming the classes of objects are directly represented as program text We will make use of the ISO module standard and represent classes as Prolog module texts The anatomy of an instance object will be such that it will be simply a Prolog term The func tor of the Prolog term will indicate the class of the instance object and the arguments will be the actual parameters of the instance object The methods of the class will be stored in a Prolog module text with the same name as the class of the object Class Class i Parameter Parameters To invoke methods on instance objects Jekejeke Prolog then provides the operator 2 This operator is bootstrapped from ordinary module operator 2 It will first determine the class of the instance object then add the instance object as a new first argument to the mes sage and finally invoke the message in the determined class Term module class Method Method 4 A We now conside
78. e logic arithmetic elem arithmetic elem runtime logic arithmetic elem arithmetic elem runtime logic bootload load arithmetic elem arithmetic round arithmetic bits runtime quali runtime quali runtime quali runtime quali runtime logic arithmetic compare arithmetic bits structure univ structure univ arithmetic compare arithmetic compare structure lexical arithmetic compare arithmetic compare arithmetic compare arithmetic bits structure lexical structure lexical structure lexical structure lexical bootload load arithmetic eval arithmetic eval arithmetic eval arithmetic eval arithmetic eval arithmetic eval arithmetic eval arithmetic bits runtime logic arithmetic bits structure univ structure lexical arithmetic elem runtime dynamic runtime session arithmetic elem bootload path jekejeke_lang_run_2019 02 _01_e docx XLOG Technologies GmbH Page 126 of 134 Jan Burse absolute_file_ name 3 absolute _resource_name 2 acos 2 acyclic_term 1 arg 3 asin 2 asserta 1 assertz 1 atan 2 atan2 3 atom 1 atom_chars 2 atom_codes 2 atom_concat 3 atom_length 2 atom_list_concat 3 atom_or_instance_of 2 atom_property 2 atomic 1 balance 1 balance 2 boolean 1 break O call 1 callable 1 ceiling 2 char16 1 char_code 2 clause 2 close 0 compare 3 compound 1 consult 1 cos 2 current_op 3 current_oper 1 current_predicate 1 current_prolog_flag 2 current_resource 1 current_source 1 decimal 1 decimal
79. e seen by the following example In the static rule for the predicate p 0 the variable X will be wrapped via a call 1 Example user D q X X SID P IsLsiealine pin q X CELY o Body conversion is also in effect when goals are executed either directly or deferred via meta arguments The body conversion can be switched off via the flag sys_body_convert The flag only affects the body conversion for the Prolog session queries for the Prolog text clauses and for the Prolog text directives The dynamic clause assertions and the deferred meta arguments are not affected by the flag these places will still do body conversion The body conversion is table driven The meta predicate declarations and determine how ar guments are traversed The predicate properties sys_body 0 and sys_rule O will indicate that the meta predicates should be traversed during body conversion respectively rule conver sion To facilitate the declaration the predicate sys_neutral_predicate 1 allows defining dic tionary entries that are not yet completely defined The following body conversion predicates are provided A The predicate cannot be executed and exists only to configure the body conversion table A B The predicate cannot be executed and exists only to configure the body conversion table A B ISO 7 8 5 The predicate succeeds whenever A and B succeed Both goal arguments A and B are cut transparent call A ISO 7 8 3
80. e source files section sys_source_preload See the module system section sys_source_visible See the module system section sys_source_name See the module system section sys_timing See the module system section sys_link See the module system section package See the module system section use_package February 23 2019 See the predicate definitions section See the source files section See the source files section See the module system section jekejeke_lang_run_2019 02 _01_e docx Page 48 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Operator Properties Operator properties can be accessed via the system predicates oper_property 2 set_oper_property 2 and reset_oper_property 2 The following predicate properties are sup ported by the Jekejeke Prolog runtime library sys_usage See the prolog texts section visible See the module system section override See the module system section sys_alias See the syntax_operators section sys_portray See the syntax_operators section February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 49 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 5 Runtime Packages The Jekejeke Prolog programming language comes with a standard set of predefined predi cates Predicates can be grouped into theories and we present them as such e Kernel Package The modules that need to be predefined by the interpreter itself e Runtime Package The modules th
81. e succeeds whenever A succeeds When an exception is thrown during the execution of A this exception is non reserved and this exception unifies with E then the predicate succeeds whenever B succeeds Otherwise the exception is re thrown sys_trap A E B The predicate succeeds whenever A succeeds When an exception is thrown during the execution of A and this exception unifies with E then the predicate succeeds whenever B succeeds Otherwise the exception is re thrown February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 56 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The following predicate properties for control predicates are provided sys_notrace The property indicates that the predicate does not appear in an exception context The property can be changed for user predicates The following source properties for control predicates are provided sys_notrace The property indicates that a call from the given definition scope does not appear in an exception context The property can be changed for user sources February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 57 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Optimization Techniques When a defined predicate is invoked the interpreter tries to find a matching clause and then invokes the body of the clause Normally the interpreter creates a choice point The choice point is used during backtracking to search for further matching claus
82. eams allow the transmission of the null character NUL O The null character does not indicate the end of a character stream or string The encoding of a resource might use character sequences such as carriage return CR r carriage return line feed CRLF r n or line feed LF n to indicate the end of a line These are made visible by a single line feed LF n through the character streams February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 27 of 134 Jan Burse Language Runtime XLOG Technologies GmbH String Syntax Strings are tokens that are started and ended by a quote character Between the quote char acter practically arbitrary characters can be used Line comments and block comments are not recognized inside strings Among the layout characters only the space can be part of a string When we want to include the quote character in a string we simply repeat it twice The single quote the double quote and the back quote can start and end a string See Simla oS VI g wu NAY esecome VW srr ehaz j YUN str Cotole gt WADE WWW WX Y esecome S W etr Gwar y JAVE str back E ues PANY S C COn S ea E E Sigamehan gt char except layout esccont gt control meta escape eol control eee hg sree age E N e I r hel eur au meta See NONE Df PS N esa TT aE escape gt OCU Cole ua Coce hex code GEE CCE gt OGE Chigit oet cigie
83. ecified While registering the Prolog interpreter will automatically create an instance of the service class with the given service number parameter Syntax dirseceiver gt UspecialaG srncdicatom ea emocduilie wa Smtec cia Mayas Example 2 Speciali foo 1 VEOoAPRI 7 is a special predicate directive An evaluable function f n is identified by the predicate property sys_arithmetic O and a predi cate indicator f n 1 To ease the end user the Prolog system automatically implements for each predicate bridging to an evaluable function and for each evaluable function tunnelling to a predicate Bridging predicate as evaluable function SC ALS JOG a op ya B Mi 3S Wi ap Gn IS ap ety cap Bap 29 6 Ye pe is OC pigg Jes throw error evaluation error partial function Tunnelling evaluable function as predicate ig Mite OO Yn X a oS aks 16 Naty 0 6p Ga 6 During bridging the arguments are evaluated and then the corresponding predicate is called with an additional last argument for the result If the corresponding predicate succeeds its choice points are removed If the predicate fails or if the result is not a value then an error is issued The bridging is further controlled by the virtual property of a predicate If a predicate has this property the first argument Y gets special treatment During bridging this argument will not be evaluated This is useful for predicates th
84. ed not be homogenously shaped and the in dexes start with one The following Prolog flags for arithmetic domains are provided bounded ISO 7 11 1 1 Legal values are true ISO and false ISO The flag indicates whether the integer do main is bounded Default value is false Currently the value cannot be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 76 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Elementary Operations When the arguments of the binary elementary operations do not have the same types then widening is applied to them before performing the operation Widening is done towards the bigger domain of the two arguments Widening from integer to float32 or float might fail with an exception since the unbounded integers have a greater range than float32 or floats The ordering of the domains is as follows integer lt float32 lt float lt decimal The binary decimal operations return the preferred scale as defined in the java class BigDec imal They thus differ from the usual float32 or float operations in that they work with unlim ited precision There is no division for decimals defined here the division will convert to float and perform a float division The signature of the available binary and unary elementary operations is listed here fy a integer x integer gt integer We number x number gt float 7 float32 x float32 gt float32 7 float x float g
85. eeds for a new callable B which is a clone of the callable A with the context property Q The following source properties for source files are provided sys_capability P The property indicates that the source has the parent capability P The property can not be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 99 of 134 Jan Burse Language Runtime XLOG Technologies GmbH last_modified L The property indicates that the source was last modified at date L The date is given in milliseconds since January 1 1970 GMT An undefined date is indicated by the value 0 The property cannot be changed version_tag V The property indicates that the source has the version tag V The version tag is an atom which starts and ends with double quotes An undefined version tag is indi cated by the empty string The property cannot be changed expiration E The property indicates that the source will expire at the date E The date is given in milliseconds since January 1 1970 GMT An undefined date is indicated by the value 0 The property cannot be changed date E The property indicates that the source was requested at the date E The date is given in milliseconds since January 1 1970 GMT An undefined date is indicated by the value 0 The property cannot be changed max_age E The property indicates that the max age of the source in seconds An undefined max age is indicated by the value 1 The property cannot be
86. eger64 1 integer64_and_not_integer32 1 integer64_or_float 1 integer64_or_float32 1 integer8 1 integer_and_not_integer64 1 is 2 last_atom_concat 3 last_sub_atom 4 last_sub_atom 5 listing O listing 1 locale_compare 3 locale_compare 4 log 2 make 0 max 3 meta_function 1 meta_predicate 1 min 3 mod 3 module 2 multifile 1 number 1 number_chars 2 number_codes 2 numbervars 3 once 1 op 3 oper_property 2 override 1 package 1 pi 1 predicate_property 2 private 1 prolog O public 1 rebuild O reexport 1 February 23 2019 Language Runtime jekejeke_lang_run_2019 02 _01_e docx XLOG Technologies GmbH reflect foreign reflect foreign reflect foreign reflect foreign reflect foreign bootload engine bootload engine runtime distributed runtime distributed bootload load reflect foreign structure type arithmetic round reflect foreign reflect foreign reflect foreign reflect foreign reflect foreign reflect foreign reflect foreign reflect foreign reflect foreign reflect foreign arithmetic eval structure atom structure atom structure atom bootload load bootload load structure lexical structure lexical arithmetic trigo bootload load arithmetic compare runtime meta runtime meta arithmetic compare arithmetic round bootload module bootload load structure type structure atom structure atom structure vars runtime logic reflect oper reflect oper bootload module bootload module arithmetic
87. ely read in from the end user The interpreter prompts each line by the query operator Each line is first converted by the term syntax and then interpreted according to the session syntax The main purpose of a session text is to answer queries against a logic program session a 4 oineiey Yoav He query gt WES lovely Examples P MM sbi al Ae Silc is a query BS XA OK i EPL bg YW alia 26 4 is a query foe The interpreter will display the bindings of the query variable names upon success of a goal If there are no interesting query variable name bindings the interpreter will display Yes The interpreter will display No upon failure of a goal When the interpreter detects choice points it will request the end user for redo The end user can do so by entering and hitting return The end user can also terminate the search by directly hitting return Upon failure of a goal if there are no choice points or if the end user terminates the search the interpreter returns to its prompt The interpreter also returns to its prompt when the goal throws an exception Before returning to the prompt the interpreter will first display the mes sage and the stack trace of the exception By entering queries that consult theory texts or up date database predicates the knowledgebase will be modified and thus further invocations of queries will return different solutions Compatibility The followi
88. es Choice point elimi nation optimization refers to the ability of the interpreter to eliminate choice points when it seems Clear that no further clauses will match From the ISO standard it is indicated to implement the cut via its own choice point So that upon back tracking the cut choice point will remove all previous choice points in the scope of the current clause and then fail Choice point elimination also refers to the early elimination of choice points by the cut The cut then does then not need to create a choice point on its own and it can deterministically succeed The omission of choice points is also possible for system and custom built ins A system built in has full control of the interpreter environment and can voluntarily eliminate choice points Inside the Prolog API there exists a protocol so that custom built ins in the form of Java foreign predicates can also omit choice points The Java method has simply not to set the retry flag upon succeeding and the invocation choice point will be discontinued Finally we have implemented optimization techniques that are based on an appropriate gen eration of an intermediate form for each clause These techniques can attack the parent stack frame the body or the head e Stack frame elimination The conditions for the application of this optimization are as follows The call has to be made from the last goal of a clause And the call has to lead into a matching clause and it has been de
89. es to an absolute path and this absolute path unifies with S The ternary predicate additionally recognizes the following path option access M M is the access read write or append The binary predicate can also be used in a backward manner absolute_resource_name R A The binary predicate succeeds when the read path R resolves to an absolute re source path A The following Prolog flags for path resolution are provided base_url The legal value is an atom The value is the base URL of the current knowledge base A missing base URL is indicated by the atom The value can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 113 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Module System A Prolog text member can be either public package local or private Private members can only be seen from within the same Prolog text Package local members will be seen from Prolog texts that share the same package name And public members are visible every where The default visibility for a member is package local inside Prolog texts elevated to modules and public for ordinary Prolog texts Examples B insimMoesie Oc lle Za Ship o X A eg X oa X 3 ee memesie Aes lt p iL 3 Error Undefined private or package local predicate member2 3 Normal Prolog texts can be turned into modules via the predicate module 2 For a nameless module the name user can be used A further convenie
90. f words Atomic elements are now atoms numbers negative numbers and references The names the empty sets and the empty lists are now found among the atoms Among the structured terms we will have compounds lists and expressions term N SSS ye ole atomic compound IRESE expression M M lt N atomic gt atom number number reference atom gt name Ww W Ww W Cree Examples X is a variable and thus a term foobar is a name and thus a term So LAS is a number and thus a term 3 is a negative number and thus a term 3 is an expression corresponds to 3 The grammatical production rules for terms can be viewed as stratified into levels This is used later for parsing operator expressions The levels range from 0 to 1200 Reading a term usually starts with level 1200 To disambiguate from operator expressions a negative number is only recognized when the minus directly precedes the first digit of the number February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 37 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compound Syntax The simplest form of structuring terms is the compound The compound consists of a name followed by one or many arguments The principal name is called the functor and the number of arguments is called the arity To disambiguate from operator expressions a compound is only recognized when the name directly precedes the left parent
91. feather animal rodent class mamal diet plant animal cat class mamal diet meat animal salmon class fish diet meat animal eagle class bird diet meat February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 118 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 6 2 Primes Example ISO For the primes example there are the following sources e primes p The Prolog text Prolog Text primes Prolog code for the arithmetic and list example x Copyright 2010 XLOG Technologies GmbH Switzerland x Jekejeke Prolog 0 8 3 a fast and small prolog interpreter yf Generate a list of integers between Low and High w integers Low High Low Rest Ow lt ikea Ly Mi sis hyo ap il integers M High Rest alimeeroeies i y 9 Il x Remove all multiples of the given prime from a list s Remove iy 7 remove I I I rem P remove Is P Nis remove I Is remove Is P Nis Detect primes and remove multiples ag Sabre ll Tsip birey PE Ls g i 1 gt nion 1 sireli LS Rikeia E Pel s remove Is I New sift New High Ps First create the numbers and then sift yf primes High R integers 2 High L Sas eLO IR February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 119 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 6 3 Money Example ISO
92. g Eee The meta predicates balance 2 3 and setup_balance 3 4 allow work distribution of a gen erate and test The meta predicates might change the order of the result set If the meta predicates are cancelled by a cut such as in a surrounding 1 or once 1 they will automati cally cancel each spawned thread The meta predicates balance 2 3 and setup_balance 3 4 assume a side effect free interac tion between the generate and test The only channels are the variables in the intersection of the generate and test and the instantiations are copied Currently the copying doesn t support attribute variables The setup in the meta predicates setup_balance 3 4 is executed once per spawned thread The setup is executed before the test and attribute variables can communicate between the setup and the test The setup can for example be used to build a CLP FD model and the model will be available in the test for labelling The following work distribution predicates are provided horde T horde T N The predicate succeeds whenever T succeeds The predicate spawns threads over the available processors running copies of T The binary predicate allows specifying the number N of requested threads balance G T balance G T N The predicate succeeds whenever G T succeeds The predicate distributes the work generated by G over the available processors running copies of T The ternary predi cate allows specifying the number N of
93. ge Runtime XLOG Technologies GmbH The Prolog text can handle execution errors via the constructs catch 3 When an execution error is fully handled that is when the execution error is not re thrown and no other execution error occurs then the Prolog query answer loop will not display any execution error and the query execution will continue as defined by the handler The Prolog text cannot handle sys tem errors since the construct catch 3 is not able to handle them System errors have a special handling When a system error of type user abort percolates to the query answer loop the interpreter will return to the Prolog prompt In case of a sys tem error of type user exit the interpreter will leave this query answer loop For all other sys tem errors the interpreter will leave all query answer loops In all cases the display of the ex ecution error message or its context is suppressed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 23 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 3 3 Source Consulting Source consulting does not stop upon the first syntax or execution error The end user can instruct the interpreter to consult a Prolog file This is easily done by issuing a query with the consult 1 predicate The predicate receives a path The clauses in the corresponding file are asserted and the directives are executed PE COMS Uke Mex CDE TONDU When a syntax error or an execution er
94. goal A has left some choice points February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 61 of 134 Jan Burse Language Runtime XLOG Technologies GmbH thread_statistics T K V The predicate succeeds for the values V of the keys K concerning the thread T The following keys are returned by the predicate sys_thread_local_clauses The number of thread local clauses threads The predicate displays the current threads statistics key value pairs February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 62 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility Matrix The following compatibility issues persist for the kernel theory Table 5 Compatibility Matrix for the Kernel Theory Nr Description System 1 Does not have predicate once DEC10 2 Has predicate unknown to control undefined predicates DEC10 3 Does not have predicates catch and throw DEC10 4 Has public directive and incore predicate DEC10 5 Has interpreter and compiled code for same predicate DEC10 6 Has mode declarations DEC10 7 Cannot compile gt 2 predicate DEC10 8 Says folding of 2 with cut not work no sys_nobarrier DEC10 9 Says cut has no declarative reading outdated view DEC10 10 No subtlety of sys_call 1 in gt 2 and 1 found DEC10 11 Leaves last call optimization open ISO 12 Leaves multi argument indexing open ISO 13 Leaves memory management open ISO Februa
95. guage The lan guage is motivated by mathematical logic but it is not fully declarative since it has still proce dural elements which destroy a simple semantic Here and there we will compare our defini tions with the Edinburgh Prolog standard 1 and the ISO Prolog standard 2 Prolog Examples We show some examples of the use of the Jekejeke Prolog pro gramming language Readers who might be interested in getting a quick grip of the Jekejeke Prolog programming language and who have already a basic knowledge of Prolog might stick to this section only Prolog Conversations The Jekejeke Prolog runtime library provides character ter minal based interactions Among the interactions we find query answering and source consulting Prolog Syntax In this section we show what syntax the Jekejeke Prolog interpreter accepts and how the syntax relates to the mathematical concepts The syntax covers multiple levels consisting of tokens terms and texts The syntax is dynamically exten sible by operator definitions Prolog Theories The Jekejeke Prolog programming language comes with a stand ard set of predefined predicates Predicates can be grouped into theories and we pre sent them as such Appendix Example Listing The full source code of Prolog examples is given February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 7 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 2 Prolog Examples We show some examples of the use
96. gument Indexing The hash table does not only point to clause sets but also to further hash tables so that recursively after a found non variable argument further non variable arguments can be searched in the calling goal When clauses are consulted or asserted no indexes are maintained by default Only after a defined predicate has been first invoked and the arguments have been analysed indexes are created The index that is created is thus dependent on the call history of the predicate Dy namic clause indexing is both available for static dynamic and thread local predicates In general the resulting indexing structure need not be the same for different hash entries When clauses are retracted and a clause set reaches zero size then the corresponding hash entry is removed The hash table automatically resizes to smaller sizes if necessary When the hash table points to a trivial clause set of size one then search continues for an alterna tive indexing argument to further restrict the clause set When building the index we also consider constraints in the body of a clause What we can currently detect are constraints of the form var X where X is a variable If an argument of an indexed clause is a variable it takes a different route into the index depending whether it is guarded by such a constraint or not When calling the predicate non variable arguments can take the non guarded route The YAP Prolog system 7 section 6 does a similar dynami
97. guments are printed in minimizing the number of spaces Pretty printing is inferred from the meta predicate declaration and the operator level February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 97 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The following syntax operator predicates are provided op L M N ISO 8 14 3 op L M N Nn ISO 8 14 3 For L lt gt 0 the predicate re defines the operator N with mode M and level L For L O the predicate undefines the operator N with mode M sys_neutral_oper l If no syntax operator has yet been defined for the syntax operator indicator defines a corresponding neutral syntax operator current_op L M O ISO 8 14 4 The predicate succeeds for every defined operator O with mode M and level L current_oper l The predicate succeeds for each user operator I oper_property l P The predicate succeeds for each property P of each user operator I The following op erator properties are supported full_name l is the qualified operator indicator nspl The operator has no space left pretty printing nspr The operator has no space right pretty printing level L The operator precende is L mode M The operator icon is M set_oper_property I P The predicate assigns the property P to the operator I reset_oper_property I P The predicate de assigns the property P from the operator I The following syntax operator properties
98. h 23 2014 0 38 e Module system introduced Jan Burse June 04 2014 0 39 e Syntax operator properties and module re export introduced Jan Burse July 14 2014 0 40 e Non essential modules and examples moved to frequent document Jan Burse August 05 2014 0 41 e Some fixes and new predicates for forward chaining Jan Burse August 22 2014 0 42 e Better printing and better foreign predicates Jan Burse February 22 2015 0 43 e Ubiquitous possibly qualified predicate indicator Jan Burse May 08 2015 0 44 e Some predicates for the new locale module and message lists removed Jan Burse May 28 2015 0 45 e Document title page introduced Jan Burse July 11 2015 0 46 e New solution REPL documented Jan Burse August 05 2015 0 47 e DCG references removed and total rework of clause retract assert zoo Jan Burse September 02 2015 0 48 e Improved foreign function interface and evaluable function handling Jan Burse October 20 2015 0 49 e Improved resource bundle handling Jan Burse December 25 2015 0 50 e New anonymous import directive Jan Burse February 15 2016 0 51 e Reference type evaluation and 2 associativity February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 5 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Jan Burse March 06 2016 0 52 e The throw 1 predicate does now context filling Jan Burse April 12 2016 0 53 e
99. he float representation of the arcus sine of X the result is in radians acos X TC2 9 3 12 Returns the float representation of the arcus cosine of X the result is in radians atan X ISO 9 3 4 Returns the float representation of the arcus tangent of X the result is in radians X Y ISO 9 3 1 Returns the float representation of X raised to the power of Y exp X ISO 9 3 5 Returns the float representation of Euler s number e raised to the power of X log X ISO 9 3 6 Returns the float representation of the natural logarithm of X sqrt X ISO 9 3 7 Returns the float representation of the square root of X pi TC2 9 3 15 Returns the float representation of Tr e Returns the float representation of Euler s number e atan2 X Y TC2 9 3 13 Returns the float representation of the arc tangent of X and Y the result is in radians February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 82 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Arithmetic Comparisons The arithmetic comparisons are more flexible than the lexical comparisons They are defined for integers floats and decimals For decimals comparison across scales is supported The same widening as already defined for the basic operations applies as well Examples lt 2 LO lt 250 0d1 00 lt 2 i Oei L00 We also provide evaluable functions min 2 and max 2 These functions are based on the aforementioned arithmetic
100. he module we want to work with into the top level This is also done by the use_module 1 directive We will import the cage module since we are interested in adult population The Jekejeke Prolog interpreter will show on the console the time and size of the loading of the module The Jekejeke Prolog interpreter will also show the loading of the di rectly or indirectly dependent modules B USS MOCNI H Cages o g nest p consulted 19 lines in 4 ms cage p consulted 18 lines in 8 ms ves We can now determine the adult population after a year P EOE Z a X X 233 The example shows that the Jekejeke Prolog interpreter will not loop when loading recursive module imports Technically the interpreter performs a traversal of a possibly cyclic import graph The example also shows that no special forward declarations are necessary to exe cuted predicates from recursive module imports Technically the interpreter lazily binds predi cates to atoms via small local caches at runtime The example can as well be run with the help of the graphical user interface of the Jekejeke Prolog interpreter on the Swing or on the Android platform The Load File respectively Load menu item can be used to find the file for the use_module 1 directive When a con sult or ensure loaded is called from within a Prolog text the directive will resolve a relative file name based on the location of the current Prolog text This exp
101. hesis compound gt WY emm LAO Wm arcom Vu aro UMS E Siw n atom LAI Y Le enrotmEente gt weran 99S T Ve Terho Ta Examples f a is a compound o a a b is a b is the empty set corresponds to is a compound corresponds to a is a compound corresponds to a b an expression corresponds to a b Ae ol o2 ee n By means of the braces a form of set notation can be invoked The empty set notation is just a short hand for the name The set notation that surrounds a term is a compound of arity one with the functor Since the empty set and the empty list do belong to the cat egory of atoms they can be used as a functor as well List Syntax A further form of structuring terms is the list A list is a short hand for multiple compounds of arity two with the functor A closed list will end in the name The vertical bar is used to denote open lists ending in the given term LES ite gt UY eeens ip jesse Ss jf Bieweakiave 2 lt Examples ol i is the empty list corresponds to Fala by 3 als a list coimcesoomcls to oa A97 MID X a ea a die el liswr Woumsasjoomels ico On 4 ABC a ie el Mase CGorresponds icO leS GG GTI The double quoted string is a short hand for a list of character codes The notation is espe cially useful in connection with
102. icate lookup the operator lookup the consult and the purge of sources by multiple threads If multiple threads access sources that depend on each other this locking might cause a deadlock since we do not the release the lock between a source and its imports Deadlocks are detected by a timeout which can be controlled by the sys_timeout Prolog flag The source dependency graph is allowed to have cycles During consult or ensure loaded a thread only processes each source once so that there is no danger of duplicate imports or an infinite import loop The dependency graph is also used by a mark and sweep algorithm to unload unused sources The user and system source does play an important role here it determines the root for the marking of the sources The following source file predicates are provided current_source S The predicate succeeds for the user absolute source paths S source_property S P The predicate succeeds for the properties P of the source path S set_source_property S P The predicate assigns the property P to the source path S reset_source_property S P The predicate de assigns the property P from the source path S sys_current_resource P Succeeds for every member P of the list of error resources current_module M The predicate succeeds for the modules M sys_context_property C Q The predicate succeeds for the context property Q of the callable C sys_set_context_property B Q A The predicate succ
103. igns the property Q to the predicate P reset_predicate_property P Q The predicate de assigns the property Q from the predicate P February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 95 of 134 Jan Burse Language Runtime XLOG Technologies GmbH sys_neutral_predicate I If no predicate has yet been defined for the predicate indicator defines a corre sponding neutral predicate sys_make_indicator F A I The predicate succeeds when is the indicator for the possibly quantified name F and the arity A The following predicate properties for predicate definitions are provided built_in The property indicates that the predicate is a built in The property cannot be changed static The property indicates that the predicate is static The property cannot be changed full_name N The property indicates that the predicate has the flattened name N The property can not be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 96 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Syntax Operators A knowledge base keeps a list of zero one or more syntax operators The syntax operators define how Prolog terms are read and written The interpreter provides the classical access to operators by the predicate op 3 and current_op 3 These predicates take respectively de liver an operator level an operator mode and an operator name If an operator has associa tivity it is possible to use
104. ilt ins and various properties Further capabilities define a product description The pro gramming interface of capabilities is currently not in the public domain But capabilities itself might be placed on the market by parties that will have access to this programming interface Capabilities that need activation can only be added with a valid activation Activations can be performed over the internet via the predicate sys_activate_capability 2 If internet access is not available an install ID can be retrieved via sys_calc_install_id 2 This install ID can be sent to the supplier by E mail surface mail phone etc who will in turn return a license text This license text can then be deposited via the predicate sys_reg_license_text 2 A capability can then be added via the predicate sys_init_capability 1 Capabilities can also be removed at any time via the predicate sys_fini_capability 1 It is recommended to remove unused capabilities since a capability migh have spawn a thread which is shutdown by the removal The currently tracked capabilities can be retrieved via the predicate sys_current_capability 1 The license for a capability might expire or be tempered with To validate it the predicate sys_check_license 1 can be called Calling the predicate only makes sense if the application cannot wait for when the system automatically validates the license The predicate sys_check_licenses 0 allows updating the knowledge base status The predicate a
105. ing functor to meta function declaration M February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 65 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The following predicate properties for meta predicates are provided meta_predicate M The property indicates that the functor has meta predicate declaration M The prop erty is single valued sys_meta_predicate S The property indicates that the predicate has been declared meta predicate in source context S The property is multi valued and can be missing The property can be changed meta_function M The property indicates that the functor has meta function declaration M The property is single valued sys_meta_function S The property indicates that the predicate has been declared meta function in source context S The property is multi valued and can be missing The following Prolog flags for meta predicates are provided sys_clause_expand The legal values are on and off The flag indicates whether the clause conversion is enabled for the knowledge base The default value is off The value can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 66 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Qualified Names For qualified names a notation based on the colon operator can be used when invoking predicates or evaluable functions The module name itself can be structured by means of the slash 2 operator and the
106. ion operator Facts consist only of a head Facts can be considered to be rules where the body corre sponds to then atom true which can then be omitted theory gt sentence sentence gt pare I VAS semcenee Wiat part gt clause directive clause gt nee Maw boei agaci head gt callable directive ame Well OOC body gt Goel wu loochky If WiexeuSs goal gt callable variable callable gt atom compound Examples La 1 I alist Gl IEICE LA Gl UE Le Gl CrS Cri Yvos ai OS A B an o S OOOO Ty Abia g ol ol Besides facts and rules a theory text can also include directives Directives are detected by a degenerated implication operator which is used prefix position Whenever a directive is encountered in a theory text the interpreter is invoked to solve the goal against the current state of the interpreter Solutions to directives are not printed and directives are only solved once The most typical directive is the operator definition directive But the application of di rectives is not limited to operator definitions To avoid common typing errors a number of sanity checks are performed on facts and rules Among these checks we find the singleton variable check This check assures that anony mous variables _ are used for variables that occur only once in a fact or rule We also find the discontinued predicate check and the m
107. ir P image_icon l big_image_icon l help_docs H shop_url U sys_notrace B D is the localized family description D is the localized product description D is the localized language description D is the localized platform description B is the need for activation true or false S is the activation status D is the localized license description T is the expiration date P is the path of the bundle storage is the image icon is the big image icon H is the list of localized document titles and their URLs U is the URL of the license provider B is the no trace flag true or false The properties act_status 1 license_descr 1 and expiration_data 1 are only available when the capability has been successful enlisted The expiration_date 1 is given in milliseconds since January 1 1970 GMT An undefined expiration_date 1 is returned as the value 0 sys_check_license C The predicate updates the license status of the capability C Throws an exception if license status is not OK sys_check_licenses The predicate updates the knowledge base status Throws an exception if the knowledge base status is not OK The following Prolog flags for capability plug ins are provided sys_act_status The value is a license error type The value indicates the activation status of the predefined and enlisted capabilities The value cannot be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 108 of
108. ise lt Mig R B SUMS eG aE R LS Xr re aca single CPU time between 1 20000 X perfect X fail true 66 multi CPU use module library runtime distributed o J ole time balance between 1 20000 X perfect X fail true February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 122 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 6 6 Pound Example For the perfect example there are the following sources e basset p The Prolog text for the basset class e dog p The Prolog text for the dog class Prolog Text basset Prolog code for the object oriented programming example Copyright 2019 XLOG Technologies GmbH Switzerland Jekejeke Prolog 1 3 5 a fast and small prolog interpreter a g f SyS aCe aTa ODECE o package library example06 module basset barking 2 reexport dog override barking 2 parkingo I VOORE ol use package library example06 oe basset lafayette bark lafayette says woof Yes o o Prolog Text dog Prolog code for the object oriented programming example Copyright 2019 XLOG Technologies GmbH Switzerland Jekejeke Prolog 1 3 5 a fast and small prolog interpreter y 8 gt SyS cde PETO IIET o package library example06 SS eNO GUslkes COC al bark Poar kino bark Self arg 1 Self Name Self barking Barking w
109. ition Networks North Holland Publishing Company Artificial Intelligence 13 231 278 http cgi di uoa gr takis pereira warren pdf ISO 2012 Prolog Part 1 General Core International Standard ISO IEC 13211 1 Technical Corrigendum 2 2012 02 15 Costa V S Rocha R and Damas L 2011 The YAP Prolog System Theory and Practice of Logic Programming 2011 http arxiv org abs 1 102 3896 Bueno F et al 2006 The Ciao Prolog System Reference Manual 2006 http www ciaohome org Legacy ciao pdf Covington M A Bagnara R O Keefe R A Wielemaker J and Price S 2011 Coding guidelines for Prolog 2011 http arxiv org abs 091 1 2899 Wielemaker J 2014 SWI Prolog Version 7 Extensions Jan Wielemaker Web and media Group VU University Amsterdam The Netherlands 2014 http www swi prolog org download publications swi7 pdf February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 134 of 134
110. ken SYNtaX erener pena eet ehh aan ees 27 ra ia VMTN SVM E Y Ee EEE age RS ae lage tec as cee aca eg eee a 37 Ard WEXUCOVIMOX canna ea dada ans eo an es ae miner eee 42 4 4 Miscellaneous Definitions x vetectacveeseosretecencteatyansetestecsteperaeneesaucetaor ented ena tee 45 5 R ntime Package S cise a re alten teh ndasad altered ated gs a E ea ae ata a a aa ea 50 Bal Kernel Package rreseranen deee E EAT REER E REAR 51 52 o untm e Fa KAGO 5 tall e a ae eats Aa e ee a Da ad ee cate i 64 5 3 Arithmetic Pack ge serenus eeta e e E E AE E E NEE EAAS 75 54 Str ct re Packages renerne ree AE A EE T AEE E ATE ETE 85 5 5 Reflect Pagkage ciun nanena eea eae e a ae o E e rE oc aoe eE 94 5 6 Bootload Package icici tetesdarteetaapehithou a E R E R 105 6 Appendix Example Listings sssseeseseeeennrrnreesseeentrrnnttsstrttttrnnttrstrnnnnnnnteseennnnnnn nenene 118 6 1 Animals Example ISO n n a a a a 118 6 2 Primes Example ISO nnper a A EE E 119 6 3 Money Example ISO isc ccscseckccies ccseesesaten cee saceenestgekcqindsceuenaeida cana peeneeensdexqedsdeheeebees 120 64 Rabbits Example nirs cest ote dsadcieheuceteat eiehonennad tcaredi teheaean dude dad eekautens nadeteheeecies 121 Acknowledgement S er etea ae bea aeea a a ae A E e Ea aA A at Aaa EEE Na Eaa a 125 WHOS XOS ETE ETE 126 PUBIC maeta l0 In E EEE E E EE E ee E E 126 Package Local Predicates ccccccecccceeeeeeeeeeeeeeeeeeeeeeeaaaaaaaaeeeeeeeeeaaaaaaaaeeeeeeeeee
111. l is raised An exception can be an arbitrary Prolog term Some exception terms are recognized by the interpreter so as to display a user friendly stack trace In particular we recognize error Message Context The exception is an error warning Message Context The exception is a warning cause Primary Secondary The exception is a composite of a primary exception and a secondary exception The predicate throw 1 can be used to throw an exception If the context is a variable the predicate will automatically instantiate the variable with the current stack trace The predicate catch 1 can be used to catch a thrown exception The predicate will not catch reserved ex ceptions Currently system errors are the only reserved exceptions The following control predicates are provided fail ISO 7 8 2 false TC2 8 15 5 The predicate fails true ISO 7 8 1 otherwise The predicate succeeds once l ISO 7 8 4 The predicate removes pending choice points between the first non cut transparent parent goal invocation and this goal and then succeeds once once A ISO 8 15 2 The predicate succeeds once if A succeeds Otherwise the predicate fails A ISO 8 15 1 When A succeeds then the predicate fails Otherwise the predicate succeeds throw E ISO 7 8 9 The predicate fills the stack trace if necessary and then raises the exception E sys_raise E The predicate raises the exception E catch A E B ISO 7 8 9 The predicat
112. lains how the module cage finds the module nest as long as they reside in the same directory February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 14 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 2 5 Parallel Example In this example we demonstrate how Jekejeke Prolog can be used for parallel search We will determine the perfect numbers between 1 and 10 000 Perfect numbers were already mentioned in Euclid s Elements and also considered by Euler A perfect number is such that the proper divisors sum up the number itself Here is how to decide 28 i 28 2 28 4 287 7 28 14 as 4b Dap A ge PP ae A eS DEE A Prolog code to check for perfect numbers needs to be able to compute the sum of a set of numbers Since Prolog does only have lists and not sets we use a list without duplicates to represent a set Summing a list can be coded as a simple recursive predicate sum_list 2 di rectly as follows s m asic lp s sum Lise Yl R g Sam SA RS B Sum tise llyg An Ty ANN 3 The above predicate could be rewritten into a predicate with an accumulator which would then be tail recursive To find the list of divisors we use the built in predicates between 3 and findall 3 The largest proper divisor can only be the size of half of the number so that we only need to search up to half of the number use _ module library advanced arith 2 naceu z osieyvecua il
113. lowing compatibility issues persist for the administration theory Table 13 Compatibility Matrix for the Administration Theory Nr Description System 1 Modes suggest multiple implementation methods DEC10 2 No API documentation therefore language binding unclear _DEC10 3 Templates suggest multiple implementation methods ISO 4 Template allows out and in out besides in parameters ISO 5 No API documentation therefore language binding unclear ISO February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 117 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 6 Appendix Example Listings The below examples can be also browsed on GitHub http github com jburse jekejeke samples tree master jekrun reference The full source code of the Prolog texts for the language examples is given The following source code has been included Animals Example ISO Primes Example ISO Money Example ISO Rabbits Example Perfect Example Pound Example 6 1 Animals Example ISO For the animals example there are the following sources e animals p The Prolog text Prolog Text animals Prolog code for the logic example Copyright 2012 XLOG Technologies GmbH Switzerland x Jekejeke Prolog 0 9 4 a fast and small prolog interpreter ef motion walk Skam EUA o diet meat class mamal motion walk skin fur class fish motion swim skin scale class bird motion fly skin
114. lts 2 As anext step the Prolog text is allowed to import other modules This is done with the use_module 1 directive The directive has to mention the file name of the module that has to be imported We will place the module cage in a file cage p and the module nest in a file nest p The directive for the import of the module nest into the module cage thus reads as follows Importing a module makes the public predicates visible P USES Moce messes s The first rule for the adults 2 predicate reads as follows It states that for the first month there is one adult pair in the cage acwles 0 I g 2 Without visibility a module predicate has to be accessed by qualifying the module name via the colon 2 operator So for example to access the babies 2 predicate inside the module nest we would need to call nest babies M Z When the module nest has been imported it is enough to write babies M Z We can take advantage of the visibility when formulating our second rule for the predicate adults 2 It states that the population of the adults grows by the number of babies ZI lbunes IN 20 8 IN S Ml sks Ned aduit SIMRO loveless IMI 74 p 2 als YEPZA February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 13 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The Prolog text of the other module nest can be found in the appendix As a next step we can import t
115. lts 2 use module nest aces 0 I s T adults N X iN M sts Neil SrelbLicg IMI SO oaos M Zp X LS Y As Prolog Text nest Prolog code for the module mutual recursion example Growth of an idealized rabbit population according to Liber Abaci from 1202 by Leonardo of Pisa known eis ADONI CCAR Copyright 2014 XLOG Technologies GmbH Switzerland Jekejeke Prolog 1 0 1 a fast and small prolog interpreter 3y module nest babies 2 use module cage lle Oj s Us paloma su Ny X N gt Or Mores Nai adults M X February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 121 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 6 5 Prefect Example For the perfect example there are the following sources e perfect p The Prolog text for the prefect number search Prolog Text perfect Prolog coce ror the parallel gearch examol Perfect numbers were deemed to have important numerological properties by the ancients and wer xtensively studied by the Greeks including Euclid http mathworld wolfram com PerfectNumber html Copyright 2019 XLOG Technologies GmbH Switzerland x Jekejeke Prolog 1 3 5 a fast and small prolog interpreter ef use module library advanced arith perfect X Vis K Z findall Z between 1 Y Z X rem Z 0 L ein Maisie ip Z 2 Suit ase ly OO stm d
116. m for semicolon in goals DEC10 6 Floating point numbers are absent DEC10 7 Integer numbers can be given in a base between 2 and9 DEC10 8 Has no lower case option ISO 2 9 Has mention of collation ISO 10 Does not have decimal syntax ISO 11 Does not have reference syntax ISO 12 Has prefix 0 for an integer that is a character code ISO 13 Has char conversion ISO 14 Has additional characters in delimiter class UNID 4 15 Has additional characters as quotes UNID February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 36 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 4 2 Term Syntax This syntax describes the grammar that forms terms from token sequences The syntax fol lows mainly the ISO core Prolog standard 6 We also incorporate some syntax extensions as known from SWI Prolog 7 10 We find the following topics e Simple Syntax At the beginning there are variables and atomics e Compound Syntax Compounds consist of a functor and arguments e List Syntax Lists are a short hand for special compounds and constants e Expression Syntax Expressions are a short hand for operator based compounds e Special Syntax Convenience for array index and dictionary terms e Compatibility Matrix SO DEC10 compatibility issues of this syntax Simple Syntax At the very beginning of terms we have the unstructured variables and atomic elements The variables have already been defined as a kind o
117. mal indicator The syntax does not express the following additional constraints It is not allowed that a number contains two underscores in a row It is not allowed that a number contains an underscore at the end of the mantissa the fraction or the exponent When the number word starts with a character indicator 0 then it is decoded as a charac ter constant The value of a character constant is the integer character code of the character that immediately follows the character indicator Character escaping as found in strings is also allowed after the character indicator February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 31 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Line Syntax The detection of lines depends on the detection of tokens and fillers A data line is a se quence of at least one token interspersed with fillers and terminated by a terminating period A terminating period is a period that is not preceded by a graphic character and that is fol lowed by a blank a line comment or that is at the end of the text Data lines are usually first detected before the term recognition process starts This allows the interpreter to detect in complete terms or superfluous tokens data gt token token filler layout linecomment non data gt filler eof token os Ler ereiavave agterecl 9 Examples abc ABC z ls El Cite MoTo By eens Is a data input P Good IOs e
118. malization and boundary built ins UNID February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 93 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 5 5 Reflect Package This theory is concerned with accessing the Prolog system The activity inside the Prolog system is distributed over multiple threads A primary thread can interrupt a secondary thread via signals Predicates can be marked as thread local Predicate Definitions Predicates can be user defined Syntax Operators Syntax operators can be user defined Source Files The Prolog system maintains of table of source files Foreign Predicates Predicates can be defined by Java methods Compatibility Matrix SO DEC10 compatibility issues of the system theory February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 94 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Predicate Definitions A knowledge base consists of zero one or more predicates Each predicate is either a built in or a defined predicate Built ins are implemented via Java methods whereas defined predi cates are implemented via associated clauses A defined predicate can have zero one or more associated clauses Each defined predicate is either static dynamic or thread local A predicate is identified by a predicate indicator imdaiiecato rni S ime xchbiley 3 stieyebleeiceue aye OMe Mumma Chester module gt package atom ee array Wee reference atom arr
119. me to N setting the source to package and setting the members L to public use_module R The predicate imports the read path R with making its predicates and syntax opera tors visible February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 114 of 134 Jan Burse Language Runtime XLOG Technologies GmbH reexport R The predicate imports the read path R with making its predicates and syntax operators visible The predicates and syntax operators along the reexport chain become also visible sys_auto_load R The predicate imports the read path R without making its predicates and syntax operators visible sys_load_resource R The predicate imports the read path R trying resolve it to a resource bundle instead of a Prolog text sys_add_resource R Add the read path R to the list of error resources private P The predicate sets the member P to private public P The predicate sets the member P to public override I The predicate sets the predicate indicator to override The following predicate properties for the module system are provided visible V The property indicates that the predicate or evaluable function has visibility V The argument V can have the values public and private The property is single valued and can be missing sys_public S The property indicates that the predicate or evaluable function has been marked public in source context S The property is multi valued and
120. mponent per knowledge base The type de pends on the current platform and toolkit The value can be changed sys_break_level The legal value is an integer The value indicates the number of currently entered breaks The value cannot be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 73 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Compatibility Matrix The following compatibility issues persist for the runtime theory Table 6 Compatibility Matrix for the Runtime Theory Nr Description System 1 Does not have the predicate dynamic DEC10 2 Has minus sign for reconsult in files list consult DEC10 3 Has save and restore predicate for the interpreter state DEC10 4 Has logging of a session DEC10 5 Has current_atom and current_functor predicate DEC10 6 The abolish predicate has two arguments name arity DEC10 7 Has reinitialise predicate DEC10 8 Uses the predicate C for terminals DEC10 9 Uses clause expansion for grammar rules DEC10 10 Mentions a predicate expand_term 2 DEC10 11 Does not have discontinuous directive DEC10 12 Does not have multi file directive DEC10 13 The predicate consult is left undefined ISO 14 The concept of a session is left undefined ISO 15 Database predicates do not have options ISO 16 Leaves clause indexing open ISO 17 _ Disallows redefining the operator ISO 18 Simultaneous infix an
121. nce is the predicate use_module 1 which does an ensure loaded of the given file specification Instead of the predicate use_module 1 also the predicate reexport 1 can be used The later predicate will make the corresponding imported members visible to qualified invocations and client imports Examples absolute file name library basic lists Y source property Y package X X library jekpro frequent basic absolute file name library basic lists Y SOURGCCPEOpe rey SVS SCUTECE mame xe 5 x Iiisics The path resolution uses prefixes from the current source and the system sources along the knowledge bases The prefixes for the current source can be set via the predicates pack age 1 and use_package 1 The prefixes for the system sources can be set via the predicate set_source_property 2 The prefixes can be queried via the source_property 2 predicate The following module system predicates are provided package E The predicate adds the prefix P to the list of prefixes of the current source Currently library 1 and foreign 1 prefixes are supported The prefix is also used as a prefix to the module 2 directive use_package P The predicate adds the prefix P to the list of prefixes of the current source Currently library 1 and foreign 1 prefixes are supported The prefix is not used as a prefix to the module 2 directive module N L The predicate is a convenience for a combination of setting the module na
122. nd can be issued from the Prolog top level by enclosing the file name in square brackets If you don t have your file name in the class path you can fully qualify the file name and consult it this way Otherwise it is enough to use the file name only 2 anaman pE Yes Upon successful consult the Prolog system will respond with a Yes The Prolog system is now ready to respond to a query We can now ask the Prolog system to guess the animal The Prolog system will search through the Prolog rules and facts and try to find a variable binding so that the query is satisfied J anne O o X Cec F No Typing the semicolon instruct the Prolog system searching for an additional solution which would not be found in the present case February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 9 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 2 2 Primes Example ISO Arithmetic and lists are also part of the Jekejeke Prolog programming language The given example computes the prime numbers up to a given upper bound by the Sieve of Eratosthe nes The graphical intuition behind it is as follows The sieve starts with listing the integer numbers starting from 2 up to some upper bound m Here is an example for m 16 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 During an iteration we pick the first uncrossed number and cross out the multiples of it E
123. nenaaaaes 130 Non Private Meta Predicates itc 5 nveet ates Gael tie er teehee teed et teat ett Gs 130 Non Private Closure Predicates iaciccrcnst esau hove tat tenvadie chore tase aired eevee Ranvieeh eee eed 130 Non Private Syntax OPSralor Ss canis cauiahesedonata tems chad tabaci hau ahealhees RamabenntadaubaemaraG 131 lA VITARE PE AET E EA FAA eee eu eet ene E a eetae 133 REEI E E E E A A Se eeiek edo ata eA Sennen 133 AGKOMYINS oes iyes etal esse e e EE Hee eek ee ie ee R RE E E 134 PREFS UCIIC OS oe cig ceases lca ate a a a bieutiieds Riel eih deat cade ety a des utente detente 134 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 3 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Change history Jan Burse November 07 2009 0 1 e Initial Version Jan Burse November 21 2009 0 2 e Added sections text syntax and structure theory Jan Burse February 229 2010 0 3 e Added sections consult theory and control theory Jan Burse March 05 2010 0 4 e Fixed some compatibility issues Jan Burse Mai 14 2010 0 5 e Enhancement of control theory Jan Burse Mai 18 2010 0 6 e Better exception handling and more compatibility issues fixed Jan Burse June 02 2010 0 7 e Better exception handling and more compatibility issues fixed Jan Burse July 02 2010 0 8 e Code styling grammar rules arithmetic operations and Prolog flags Jan Burse September 02 2010 0 9 e Bitwise opera
124. ng compatibility issues persist on the line level Table 4 Compatibility Matrix for the Text Syntax Nr ___ Description System 1 Has no singleton variable check DEC10 2 Has no discontinued predicate check DEC10 3 Has no multi file predicate check DEC10 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 44 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 4 4 Miscellaneous Definitions The interpreter also needs to keep track of flags and properties definitions The following flags and properties are provided by the Jekejeke Prolog runtime library e Prolog Flags The predefined Prolog flags e Predicate Properties The predefined predicate properties e Source Properties The predefined source properties e Operator Properties The predefined operator properties February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 45 of 134 Jan Burse Prolog Flags Language Runtime XLOG Technologies GmbH Prolog flags can be accessed via the system predicates current_prolog_flag 2 and set_prolog_flag 2 The following Prolog flags are supported by the Jekejeke Prolog runtime library February 23 2019 sys_attached_to sys_belongs to sys_break_level sys_choice_point sys_body_variable sys_stack_frame sys_head_variable sys_clause_index sys_last_pred sys_ timeout verbose sys_body_convert sys_clause_expand bounded integer_rounding_function max_arity max_code ba
125. ning dieresis UML x308 Among the non decimal digits number types we find roman numbers and fractions We did not imple ment any composing or decomposing conversion of character sequences to other character sequences As a result convertible character sequences are not recognized as identical Uppersconrei WPAN NC NSIsh Is AIEHR TITLECASE LETTER CONNECTOR PUNCTUATION lower gt LOWERCASE LETTER MODIFIER LETTER OTHER_LETTER NON SPACING MARK ENCLOSING MARK COMBINING SPACING MARK ETTER NUMBER OTHER NUMBER Pron OCA at e seo OD gt Examples ERN The variable _ A Starts with dashed low line ep The variable Mep Starts with digraph dzhe Dzep The variable Dzep different from first variable a lt UML gt The name a The name a different from first name VII The name VIl Roman seven 15 The name Fraction 1 3 We added the non decimal digit numbers to the lower letter class since we cannot offer some sensible number conversion for them Therefore although they resemble numbers they will only be detected as names When preceded by a decimal digit they need to be quoted On the other hand the Unicode decimal digit number character type has a good support We can use digits in various scripts and they are converted into numbers To avoid the conversion one has to
126. not allowed to include an end of line Instead the escape sequences for the line feed n should be used A backslash followed by an end of line is used to continue a string on the next line Strings are also not allowed to include layout characters These have to be escaped as well February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 28 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Word Syntax Words are tokens that are not enclosed by some characters Character classes determine the border from one word to another We have defined the classes of delimiters alphabetical characters decimal digits and graphic characters Delimiters are characters that form a word by their own Alphabetical characters and digits glue together to form words Similarly graphic characters form a word when arranged in sequence word gt delimiter ehoas t ailing Ghieplic p lt cfieaioleske f Caseyolasne jj number reference delimiter gt W CH ee Ww wa W a a Hs W ae Wea UP A W ALES alpha gt upperscore lower upperscore aU eee a eats lower Se UE hoe ae NAS Glej Sa IW aA RO graphic gt WN Ww wen wu nyo W Q WwW Up 1 pe l i wow Wk rf UN MW Woe aa WoW CESS Numbers and references share in common that they start with a digit Their syntax is docu mented in more detail in the next section Words are further classified into names variables
127. ntax error description DEC10 2 Directives are not viewed as arbitrary goals ISO 3 The initialize directive allows arbitrary goals ISO 4 Consulting is not part of the standard ISO February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 25 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 4 Prolog Syntax In this section we show what syntax the Jekejeke Prolog interpreter accepts and how the syntax is interpreted relates to the mathematical concepts The syntax covers multiple levels consisting of tokens terms and texts The syntax is dynamically extensible by operator defi nitions Each level can be characterized as follows e Token Level The smallest unit above characters are tokens The interpreter recog nizes a number of different tokens e Term Level The tokens of a line are then assembled into terms The operator defini tions control the assemblage of terms with infix or prefix operators e Text Level On the text level we find the terms that are either used in a user session or that are consulted from a file e Miscellaneous Definitions The interpreter keeps track of flags and properties February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 26 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 4 1 Token Syntax This syntax describes the grammar that forms tokens from character sequences The syntax follows mainly the ISO core Prolog standard 6 The Unicode extensions is based on
128. nterpreter state or the goal can be used to query the interpreter state Besides that the end user can also use session predicates such as abort 0 break O etc or predicates he has defined on his own This is what happens when the end user chooses the semicolon February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 20 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The interpreter internally works with unnamed variables Query variables are mapped to these unnamed variables When displaying an answer the interpreter maps the unnamed variables back to the query variables Anonymous variables which are an underscore only _ are not shown to the end user February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 21 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 3 2 Error Handling Syntactically incorrect queries are ignored by the Prolog query answer loop The end user might issue queries that are not syntactically correct Here is an example ey ae The interpreter detects syntax errors and reports them to the end user The query text except for the initial comments is repeated and the error position is indicated Also the syntax error message is displayed Error Term missing a Queries with syntax errors are not executed and the interpreter returns to its prompt It can further happen that a query causes an unhandled execution error du
129. of the Jekejeke Prolog programming language Readers who might be interested in getting a quick grip Jekejeke Prolog programming language and who have already a basic knowledge of Prolog might stick to this section only Animals Example ISO The Jekejeke Prolog programming language provides the usual logical operators The given example shows a small expert system Primes Example ISO Arithmetic and lists are also part of the Jekejeke Prolog pro gramming language The given example computes the prime numbers up to a given upper bound by the Sieve of Eratosthenes Money Example ISO The Jekejeke Prolog programming language provides the usual backtracking The given example shows the solving of a small letter puzzle Rabbits Example Jekejeke Prolog allows the grouping of predicates to modules The given example shows mutual recursion among modules Parallel Example Jekejeke Prolog provides easy to use parallel generate and test As an example we determine perfect numbers Pound Example Jekejeke Prolog allows object oriented programming based on ISO modules including inheritance of methods by sub classes February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 8 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 2 1 Animals Example ISO The Jekejeke Prolog programming language provides the usual logical operators The given example shows a small expert system The knowledge of the expert systems is represented as
130. onding radix is expected There is the binary radix indicator Ob the octal radix indicator Oo and the hex radix indicator Ox Currently only integers can be provided with a non decimal radix Floats and decimals do not currently have this feature number gt integer float decimal reference gt VOCH Mex Cge Mex Cueit Yo integer gt Ol doim Chee d louie ehete Yo OO OGre Cheie d OCU Chiechie a BOA mex Chepe f ae Cheie ea veal eee Buen ANN Sseeioe YY Glew clas mantissa float gt mantissa fraction exponent vort I mantissa lie reaction L exponam Io decimal gt VOW menrrissea rracciom exponsme Ils mantissa gt gt Chote chigaic YY dh fraction gt 7 cligalic i clakgaic YY dc exponent gt Ye Win Va wee i eien f cligatc loubia _Glalieatic ee OS caer MELE When the number word starts with a reference indicator Or then it is considered a refer ence References can only be written to an output stream but they cannot be read in from an input stream If an attempt is made to read a reference from an input stream then a syntax error is thrown When the number word starts with a small float indicator Of then it is converted into a small float constant The conversion might fail when the number word does not conform to the small float syntax or when the number is outside of the representation
131. onsole does not abolish its previously consulted predicates It can thus be used to add more and more predicates to the knowledge base Predicates have to be manually reset by means of the system predicate abolish 1 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 24 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 3 4 Interrupt Handling The native console allows manually interrupting the interpreter loop either during read or dur ing execution The interrupt key C on Mac Linux and Windows will cause the invocation of an interrupt handler which will affect the interpreter For the runtime library we decided to assign the exit function to the interrupt key When the interrupt key is pressed the interrupt handler will signal a system error of type user exit When not otherwise trapped this will cause an exit of the current session gt Jekejeke Prolog Runtime Library 1 0 7 c 1985 2015 XLOG Technologies GmbH Switzerland repeat fail AG gt In the above example the interpreter hangs in an infinite computation from the repeat fail query The interrupt key allows terminating this infinite computation 3 5 Compatibility Matrix We compare our approach with the former DEC10 standard and the current ISO core stand ard The following compatibility issues persist for the interactions Table 1 Compatibility Matrix for Interactions Nr Description System 1 Does not have sy
132. our own research We find the following topics e Filler Syntax Fillers are for layout and comments e String Syntax Strings use quotes to enclose characters e Word Syntax Words are based on character classes e Number Syntax Numbers are used to denote integers and floats e Line Syntax Lines are sequence of tokens terminated by a period e Unicode Extension Jekejeke Prolog supports the Unicode character set e Compatibility Matrix SO DEC10 compatibility issues of this syntax Filler Syntax In the following presentation we only assume an ASCII encoding The token syntax here is thus defined based on the 7 bit characters from ASCII There is a separate section that shows how the token syntax is extended to Unicode The tokens can be interspersed with layout characters and comments There are two kinds of comments namely line comments and block comments A line comment starts with and ends with an end of line A block comments starts with and continues until the closing filler gt Jlehyouc linecomment blockcomment layout met WAKO NURS es eth IME linecomment UY e ehan Soll eol gt n blockcomment a Wy oleae fey Examples hanoi Solves the towers of hanoi problem is a line comment hanoi Solves the towers of hanoi problem o is a block comment Besides the space character all ASCII control characters count as layout characters The un derlying str
133. pared and finally the arguments from left to right The predicate compare 3 returns lt or gt Examples f i lt 2 0 No LOOM caiacy O mulapme 7 O ee O gt Reference types can always be used in equality tests Whether a reference type can be com pared depends on whether it implements the Java Comparable interface The predicates locale_compare 3 4 allow a locale comparison In locale comparison the atoms and functors are ordered according to a locale specific Java collator Locale comparison for reference types is not yet supported The following built in predicates are provided X Y ISO 8 4 1 The predicate succeeds when X is lexically equal to Y X Y ISO 8 4 1 The predicate succeeds when X is not lexically equal to Y X lt Y ISO 8 4 1 The predicate succeeds when X is lexically before Y X lt Y ISO 8 4 1 The predicate succeeds when X is lexically before or equal to Y X gt Y ISO 8 4 1 The predicate succeeds when X is lexically after Y X gt Y ISO 8 4 1 The predicate succeeds when X is lexically after or equal to Y compare O X Y TC2 8 4 2 The predicate succeeds when O unifies with the result of comparing X to Y The re sult is one of the following atoms lt or gt locale_compare O X Y locale_compare C O X Y The predicate succeeds when O unifies with the result of locale comparing X to Y The result is one of the following atoms lt or gt
134. pond to parenthesis or quotes As a result these characters do not glue with other charac ters Further important Prolog punctuations characters such as and are detected individually The delimiter class also contains our invalid character class An invalid charac ters delimiter is allowed during tokenization but sorted out during parsing GlSlibmabeeic gt SWART PUNCTUSETON February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 33 of 134 Jan Burse Language Runtime XLOG Technologies GmbH END PUNCTUATION INITIAL QUOTE PUNCTUATION FINAL QUOTE PUNCTUATION wow en t wow UETAN invalid Examples gt The name followed by the name We will use the Unicode connecting punctuation character type to detect the underscore The underscore detects the start of variables We also added the Unicode uppercase character types and the Unicode title character types to the corresponding character class This leaves fully intact the detection of ASCII variables But it broadens what will be detected as Unicode variables For example dashed low lines and certain digraphs now indicate also variables We filled the remaining class of lower letters with all remaining Unicode letter character types all Unicode mark character types and all non decimal digit number types Among the mark character types we find for example the combi
135. put the digits in quotes chigit mo IDO IUMVAL IDG IER INUIMIS INR February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 34 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Examples Ue The name 2 The number 2 and the name 2 o2 Wae mame Vin diailo ale vase 3 The number 0 oe We have now covered almost all Prolog text character classes What remains is the graphic character class We assign to this character class all the Unicode character types that we did not yet assign The dollar sign is still covered by the Unicode currency symbol character type Similarly it can be verified that all other ASCII graphic character classes are still cov ered Also using Unicode character types broadens this character class For example the euro currency symbol is now also included as a graphic character Since graphic characters only glue with them selves and don t glue with delimiters alphabeti cal characters and decimal digits they can be still written directly adjacent to numbers and non graphic names Math symbols are now also part of the graphic character class so care has to be taken when using these symbols adjacently with each other or in front of a period When in doubt best is to use spaces between these symbols Useful math symbols are for example the right arrow x2192 or the bottom L x22A5 graphic gt DASH
136. r thread local assertz C ISO 8 9 2 The predicate inserts the clause C at the bottom The head predicate must be dy namic or thread local abolish P ISO 8 9 4 The predicate removes the predicate evaluable function or syntax operator The following predicate properties for dynamic databases are provided dynamic The property indicates that the defined predicate is shared dynamic The property cannot be set sys_dynamic S The property indicates that the predicate has been marked dynamic in source context S The property is multi valued and can be missing thread_local The property indicates that the clauses are local to the interpreter The property can not be set sys_thread_local S The property indicates that the predicate has been marked thread local in source con text S The property is multi valued and can be missing group_local The property indicates that the clauses are local to the knowledge base The property cannot be set sys_group_local S The property indicates that the predicate has been marked group local in source con text S The property is multi valued and can be missing February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 72 of 134 Jan Burse Language Runtime XLOG Technologies GmbH User Session The query answer loop of the Prolog interpreter repeatedly prompts a query and answers it by showing the variable bindings The query answer loop can be entered recursively by the predica
137. r a dog pound We assume that there is a class dog that determines the be haviour of dogs through its methods Further we assume that a dog instance has a name di rectly found in the first parameter The method bark 1 is a dog command The method bark ing 2 is used to retrieve the barking sound of a dog module dog bark 1 barking 2 lowes Seltik arg 1 Self Name Self barking Barking write Name write says Witt ex Barsketr ep es awit ou Ge sat ME loysliolealigves 7 seiblicae Both methods are implemented so that they adhere to the convention of the Jekejeke Prolog operator 2 Namely they have a first argument for the instance object itself This conven tion was adopted from Python which features the same manner of defining methods We can now send the bark command to different dogs 2 CoG suisas s soeka SUS Says DULE Yes B doglar olem s sloani SHewOlhelay SaYAS TewUGEI Mes February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 17 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Before consulting the above Prolog text make sure to have the path set via sys_add_path 1 Further place a package directive use_package 1 into the Prolog text and before top level queries so that short class names can be used We now consider programming of sub clas ses The ISO module standard reexport 1 directive serves as an inheritance indicator Text Text
138. r double colon 2 notation A qualified functor may only contains the colon 2 notation The predicate sys_get_module 2 can be used to retrieve the class reference or module name of a receiver The following qualified names predicates are provided M C The predicate calls the callable C by qualifying the predicate name of C by the mod ule name M The call is performed in the same call site as the colon notation R C The predicate calls the callable C by qualifying the predicate name of C by the mod ule name of R and prepending R itself The call is performed in the same call site as the colon notation sys_callable T February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 67 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Check whether T is a fully qualified callable sys_var T Check whether T is a half qualified or not a qualified callable sys_functor T F A The predicate unifies F with the possibly quantified functor of T and unifies A with the arity of T sys_univ T F L The predicate unifies F with the possibly qualified functor of T and unifies L with the arguments of T sys_get_module O M The predicate succeeds in M with the class reference or module name of O sys_replace_site Q S P The predicate succeeds for a new callable B which is a clone of the callable A with all the site properties of the callable Q The following qualified names evaluable functions are provided
139. r_variables 4 helps in creating a variable names map The resulting variable names map can be used with the predicates write_term 2 3 The variable names map from the current top level query can be retrieved via the predicate sys_get_variable_names 1 The predicate will skip non variable and duplicate entries In the case of duplicates the entry with a lower dereferencing count is preferred The result is in tended to be used with the predicates write_term 2 3 The following term variable predicates are provided term_variables X L TC2 8 5 5 term_variables X L R The predicate succeeds when L unifies with the variables of X The variant with a third argument produces a difference list sys_term_singletons X L The predicate succeeds when L unifies with the variables of X that occur only once sys_goal_kernel G K The predicate succeeds when K unifies with the kernel of the goal G sys_goal_globals G L The predicate succeeds when L unifies with the global variables of the goal G numbervars X N M The predicate instantiates the un instantiated variables of the term X with compounds of the form VAR lt index gt The lt index gt starts with N The predicate succeeds when M unifies with the next available lt index gt sys_number_variables V N S M The predicate succeeds with variable names M resulting from giving names to the variables in V respecting the variable names N and the unnamed singletons S ground X
140. requested threads setup_balance S G T setup_balance S G T N The predicate succeeds whenever S G T succeeds The predicate distributes the work generated by G over the available processors running copies of S T The ter nary predicate allows specifying the number N of requested threads submit C N The predicate succeeds in running a copy of the goal C in a new thread and unifies N with its new name cancel N The predicate succeeds in stopping the thread with the name N February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 70 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Dynamic Database Static dynamic and thread local predicates can be consulted Dynamic and thread local predicates on the other hand can be also accessed and modified by the predicates here in The predicate clause 2 matches clauses the predicate retract 1 matches and removes clauses and the predicates asserta 1 and assertz 1 add a clause Examples 2 assertz p a Yes B jon s X a clause p X Y X a YS Ceis The predicates clause 2 retract 1 and retractall 1 can only match clauses that are visible from the head predicate that is used in the search The predicates asserta 1 and assertz 1 cannot redefine a predicate Instead it must be marked multi file The clauses of a dynamic predicate are seen by all threads A thread local predicate on the other hand has its own set of clauses for each thread
141. ring its execution The Prolog query answer loop aborts the query upon unhandled execution errors Here is an ex ample R APOOleUes When an unhandled execution error happens the interpreter will stop searching and report it to the end user The execution error message and its context will be display For affected goal originating in the query the contexts will simply consist of the predicate identification Error Undefined predicate foobar 0 foOObare 10 2 When the affected goal originates from a source file a more elaborated context is displayed In particular the context will also show the file name of the absolute source path together with a line number where the affected goal can be found The context will also show the stack trace from the affected goal back to the top level B til Error Undefined predicate foobar 0 rooe 0 alin Vesncejoiestoimsio ee 5 ES A 0 shin Exertion o ic 3 tA O im excagrc on 9 aw Al cl 7 O The stack frame elimination optimization will remove stack frames from the call chain As a result the stack trace will be shortened In the extreme only the affected goal together with the query answer loop goal will remain in the call chain B Bly Error Undefined predicate foobar 0 hoOObar f O Tm excepcion eats i2 sil 7 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 22 of 134 Jan Burse Langua
142. rite Name write says write Barking write nl lose eauiave EEUE use package library example06 o 2 JOG susi s loek Susi says PUTE es ol foe K February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 123 of 134 Jan Burse Language Runtime XLOG Technologies GmbH z COG larr ralan s socn Smrolkehiks ayo E EURE Yes ol ol February 23 2019 jekejeke_lang_run_2019 02 01_e docx Page 124 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Acknowledgements We are grateful to Bart Demoen KU Leuven for participation in discussion on ISO compati bility and body conversion of Jekejeke Prolog 0 9 1 We would like to thank Ulrich Neumerkel Technische Universitat Wien for testing the syntax and the console of Jekejeke Prolog 0 9 1 and handing us around 50 findings Further thanks go to Jos De Roo Agfa Healthcare for providing us a critical test case for the indexing and for meta arguments of Jekejeke Prolog 0 9 7 February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 125 of 134 Jan Burse Public Predicates Predicate 13 kk 3 gt 2 2 3 2 2 3 gt 2 2 13 113 0 3 4 V 5 6 7 8 1 9 2 1 V 3 2 2 13 abolish 1 abort 0 abs 2 absolute_file_ name 2 February 23 2019 Language Runtime Indexes Module arithmetic elem arithmetic trigo runtim
143. rolog runtime library provides character terminal based interactions Among the interactions we find query answering and source consulting e Solution REPL We explain the Prolog query answer loop which consists of a query answering session between the Prolog system and the end user e Error Handling The Prolog query answer loop aborts the query upon syntax errors or unhandled execution errors e Source Consulting Source consulting does not stop upon the first syntax or execu tion error e Interrupt Handling The console allows manually interrupting the interpreter loop ei ther during read or during execution e Compatibility Matrix We compare our approach with the former DEC10 standard and the current ISO core standard February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 19 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 3 1 Solution REPL We explain the Prolog query answer loop which consists of a query answering session be tween the Prolog system and the end user The interpreter announces that it can accept que ries by the Prolog prompt The end user can type in his query terminate it by a period and issue it with a carriage re turn The syntax of a query is documented in the language reference manual in section 3 4 Let s turn to our first example query The query will display the text Hello World and new line in the console B Weis Cello Worle AY talk
144. ror from a clause or directive is encountered the con sult predicate does not abort Syntax errors are displayed and the corresponding clause is not asserted respectively the corresponding directive is not executed Error Term missing COGO g5 exception p at 1 The syntax error will be displayed together with its source location and the stack trace Exe cution errors related to the assertion of clauses will also be shown with their source location and the stack trace Error Can t modify system built in or static predicate write 1 exception p at 3 Not all problems related to the assertion of clauses are so fatal as to prevent the interpreter from adding the clause to the knowledge base When the interpreter encounters such a mi nor problem it issues a warning instead of an error Warning Singleton variable s Y use anonymous variable s _ exception p at 5 The special source name user is reserved for consulting from the console The source name can be used without further specifications and it instructs the interpreter to read clauses and directives directly from the console window The consult from console ends with an end of file D on Mac and Linux Z on Windows 2 consult user member X X _ mieruloysie y I Sa B umsiulevsie OK 36 o sMemmlosie O WINCW Wiens Oo ink enile TANS 65 66 67 Yes The consult from the c
145. rwise if X is a number then the predicate succeeds when Y unifies with the corresponding character list number_codes X Y ISO 8 16 8 If X is a variable and Y is a code list then the predicate succeeds when X unifies with the corresponding number Otherwise if X is a number then the predicate suceeds when Y unifies with the corresponding code list last_atom_concat X Y Z The predicate succeeds whenever the atom Z is the concatenation of the atom X and the atom Y Works like the ISO predicate atom_concat 3 except that non deterministic results are enumerated in reverse order last_sub_atom X Z T U last_sub_atom X Y Z T U The predicate succeeds whenever the atom U is the sub atom of the atom X starting at position Y with length Z and ending T characters before Works like the ISO predi cate sub_atom 5 except that non deterministic results are enumerated in reverse or der atom_split L S R Prolog Commons Atom Utilities If R is a variable the predicate succeeds when R unifies with the concatenation of each atom from the non empty list L separated by the atom S Otherwise the predicate splits the atom R into a list L of atoms that are separated by the atom S atom_number A N Prolog Commons Atom Utilities If A is a variable then the predicate succeeds in A with the number unparsing of N Otherwise the predicate succeeds in N with the number parsing of A atom_block A B If A is a variable then the predicate succeeds
146. ry 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 63 of 134 Jan Burse Language Runtime XLOG Technologies GmbH 5 2 Runtime Package This theory groups the minimal set of predicates that are usually defined for the interpreter e Meta Directives Functors can be marked as taking goal and clause arguments e Qualified Names Predicates and evaluable functions can be qualified e Logical Predicates Some logical extensions of the interpreter e Work Distribution Some meta predicates to distribute work e Dynamic Databases Knowledge bases can be dynamically manipulated e User Session Predicates can be interactively executed by submitting queries e Compatibility Matrix SO DEC10 compatibility issues of the consult theory February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 64 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Meta Directives The meta predicate declaration takes as an argument a predicate name and a number of meta argument specifiers Analogously the meta function directive takes as an argument a function name and a number of meta argument specifiers We can describe the arguments via the following grammar rules meta directive gt imeta joicseliesica mera Salemrencwucs Munsee acwblaketcakoue Mere Salonavehe were meta signature MOG Wma sme Mae wiRe peme WY mera iSjersyelalic see if vu merca sfoxSesicalee jp 9 Te meta specifier gt integer monn Ess E mera
147. se_url sys_act_status jekejeke_lang_run_2019 02 _01_e docx See the user session section See the user session section See the user session section See the optimization techniques section See the optimization techniques section See the optimization techniques section See the optimization techniques section See the clause indexing section See the prolog texts section See the prolog texts section See the prolog texts section See the body conversion section See the meta predicates section See the arithmetic domains section See the rounding operations section See the building and unification section See the string predicates section See the path resolution section See the capability plug ins section Page 46 of 134 Jan Burse Predicate Properties Language Runtime XLOG Technologies GmbH Predicate properties can be accessed via the system predicates predicate_property 2 set_predicate_property 2 and reset_predicate_property 2 The following predicate properties are supported by the Jekejeke Prolog runtime library February 23 2019 sys_body sys_rule sys_notrace sys_nobarrier built_in static full_name sys_usage multifile sys_multifile discontiguous visible sys_public override meta_predicate sys_meta_predicate meta_function sys_meta_function dynamic sys_dynamic thread_local sys_thread_local group_local sys_group_local virtual sys_arithmetic jekejeke
148. set 1 operator This gives rise to a new primitive goal syntax which reads as follows goal gt mocks V8 Coeil receiver goal callable receiver gt package callable reference callable Under the hood qualified names are flattened to atoms with the help of an inline atom cache Further the colon notation will also resolve module names based on the class loader of the call site the prefix list of the call site and the prefix list of the system A qualified predicate will be also searched in the re export chain of the given module name Examples basic lists member X 1 X 1 jekpro frequent basic lists bmember X 1 X 1 Finally there is also a double colon notation based on the 2 operator that can be used to send message to a receiver The receiver itself is prepended Python style to the callable be fore invoking it For auto loaded Java classes the re export chain contains the super class and implemented interfaces If an unqualified predicate with the same name is defined then this fall back is called Examples a VGysicem serie 04 XS ejowabimicilia Yel o Xe Ora PSS eal B Olas Sicicioie OO KS svineieS raoe K sil abc X Or398aef8b The predicates sys _callable 1 sys_var 1 sys _functor 3 and sys_univ 2 are the adaptations of callable 1 var 1 functor 3 and 2 in that these predicates respect the module colon 2 and receive
149. ssumes that the licenses of the enlisted capabilities have already been validated The following capability plug in predicates are provided sys_activate_capability C H The predicate activates the capability C by the license key H sys_calc_install_id C I The predicate calculates the install ID for the capability C and unifies it with I sys_reg_license_text C T The predicate registers the license text T for the capability C in the user preferences sys_reged_license_text C T The predicate returns the registeres license text in T for the capability C in the user preferences sys_init_capability C sys_init_capability C O The unary predicate initializes and enlists the capability C The binary predicate additionally recognizes the following init options prompt B B is prompt true or false default value is false sys_fini_capability C The predicate removes the capability C sys_current_capability C The predicate succeeds with the currently initialized capabilities C February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 107 of 134 Jan Burse sys_capability_property C P Language Runtime XLOG Technologies GmbH The predicate succeeds with all the properties of the capability C that unify with P The following capability properties are supported family_descr D product_descr D language_descr D platform_descr D needs_act B act_status S license_descr D expiration_date T bundle_d
150. t float 7 decimal x decimal gt decimal abs sign integer gt integer abs sign float32 gt float32 abs sign float gt float abs sign decimal gt decimal Examples abs 1 il abs 1 0 gt 1 0 abs 0d1 00 gt 0d1 00 9 1 gt 10 0 99 0 01 gt 1 0 0d0 990 0d0 01 gt 0d1 000 5 2 gt 10 50 amp 220 gt 10 0 0d5 0 0d2 0 gt 0d10 00 Bene gt 2 5 5 0 20 gt 2 5 0500 2 gt 2 5 3 A 27 gt 7625597484987 The unary float32 respective float conversion is approximate for integer and decimal argu ments and returns always float32 respective float The unary decimal conversion is exact for integer float32 and float arguments and returns always decimals The signature of the available unary conversion operations is listed here float32 number gt float32 float number gt float decimal number gt decimal February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 77 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Examples decimal 0 1 gt 0d0 1000000000 0000000555 1115123125 7827021181 5834045410 15625 Thanks to tunnelling an evaluable function can also be invoked by calling the corresponding predicate When invoking the predicate the arguments are not evaluated only type checked The result of the evaluable function is returned in the last argument of the predicate Examples
151. te break O The query answer loop can be terminated by issuing an end of file The query answer loop runs in its own input output stream pair The system predicates abort 1 exit 1 and close 1 throw some well known system errors The system predicate exit 1 allows terminating the query answer loop similarly like issuing an end of file The system predicate abort 1 only terminates the current query but continues the loop The system predicate close 1 recursively terminates all query answering loops The system predicate version 0 displays a version banner Top level answers are displayed with the operator 2 For custom forms delivered by a printable hook the operator is 2 is displayed For custom constraints delivered by an equation hook the corresponding operator is displayed For printable and equation hooks see the module residue The following user session predicates are provided prolog break The predicate prompts and answers queries until an end of file is encountered abort The predicate throws a system error of type user abort exit The predicate throws a system error of type user exit close The predicate throws a system error of type user close The following Prolog flags for user sessions are provided sys_attached_to The legal value is a graphic interface component per interpreter The type depends on the current platform and toolkit The value can be changed sys_belongs to The legal value is a graphic interface co
152. tected that no further clauses will match The call chain will then be shortened e Body variable elimination This optimization technique is capable of eliminating body variables This is done by special reference count decrementing instructions in side the intermediate form Also place holder creation is delayed into the body e Head variable elimination This optimization technique can eliminate head varia bles This is done by special unification instructions that can combine goal arguments directly Also unifications are delayed into the body The following Prolog flags for the optimization techniques are provided sys_choice_point Legal values are on and off The flag indicates whether choice point elimination is en abled for the knowledge base Default value is on Value can be changed sys_body_variable Legal values are on and off The flag is per knowledge base and is inherited when predicates are created Default value is on The value can be changed sys_stack_frame Legal values are on and off The flag is per knowledge base and is inherited when predicates are created Default value is on The value can be changed sys_head_variable Legal values are on and off The flag is per knowledge base and is inherited when predicates are created Default value is on The value can be changed February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 58 of 134 Jan Burse Language Runtime XLOG Technologies GmbH The following Pre
153. ter of type CallOut is needed for non deterministic foreign predi cates The API of the CallOut allows fine control of the creation of choice points of the choice point data of clean up handling and barrier handling For more information one should consult the programming interface documentation February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 101 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Table 10 Parameter Type Mapping Java Type Prolog Type java lang String atom java lang CharSequence atom or reference java lang Boolean boolean atom from the set true false java lang Byte byte integer between 2 7 and 247 1 java lang Char char char between 0 and 216 1 java lang Short short integer between 2 15 and 2 15 1 java lang Integer int integer between 2431 and 2431 1 java lang Long long integer between 2 63 and 2 63 1 java math BigInteger integer java lang Float float float32 java lang Double double float java math BigDecimal decimal java lang Number number jekpro tools term AbstractTerm term java lang Object term non arrays reference arrays reference jekpro tools call Interpreter The current interpreter jekpro tools call Callout The current call out The interpreter allows InterpreterException and InterpreterMessage exceptions thrown by the Java method For InterpreterMessage the Prolog st
154. tions set predicates and more compatibility issues fixed Jan Burse October 02 2010 0 10 e Predicate testing predicates and more compatibility issues fixed Jan Burse November 08 2010 0 11 e Data types reference and decimal introduced Jan Burse November 18 2010 0 12 e Number and string syntax enhanced Jan Burse November 22 2010 0 13 e String predicates and character input output enhanced Jan Burse November 24 2010 0 14 e Basic stream control introduced and input output by stream arguments enhanced Jan Burse December 02 2010 0 15 e Advanced stream control and module transparent introduced Jan Burse January 02 2011 0 16 e Stream and consult theory enhanced Jan Burse April 15 2011 0 17 e Unicode extension document syntax enhanced and stream theory enhanced Jan Burse April 25 2011 0 18 e Development theory moved into separate document and capability predicates Jan Burse Mai 06 2011 0 19 e Clause expansion flags amp properties and source files section introduced Jan Burse June 15 2011 0 20 e Multi threading and byte I O section introduced Jan Burse August 11 2011 0 21 e Definite clause grammar strings variable names and Unicode handling updated Jan Burse August 23 2011 0 22 e Clause indexing and optimization sections updated Jan Burse September 17 2011 0 23 e Kernel predicate and signal handling section updated Jan Burse October 06 2011
155. ulti file predicate check These checks assure that in the normal case all the facts and rules for a predicate are defined in one row and that they only come from one source The head of a rule or fact needs to be a callable That is it has to be either an atom or a com pound It is not possible to have rules or facts for numbers or variables Internally the Prolog interpreter only supports natively conjunctions 2 in the body All other constructs in the body have to refer to predicates defined in the knowledge base This includes logical predi cates such as 2 2 gt 2 and 1 which are predefined defined by the system If a predicate cannot be found an existence exception is thrown during execution It is possible to combine multiple clauses and directives into a single input line by means of the 2 operator or to indicate no clause and no directive by the atom unit This is useful for returning multiple clauses and directives by term expansion The operator 2 has been chosen in remembrance of hypothetical reasoning but it works slightly different Clauses and directives that are joined via 2 during consult give not raise to inter clausal variables The individual clauses are still automatically universally quantified February 23 2019 jekejeke_lang_run_2019 02 _01_e docx Page 43 of 134 Jan Burse Language Runtime XLOG Technologies GmbH Session Syntax A session text is a set of lines usually interactiv
156. ute file name my folder my file X Error File my folder my file not found absolute file name 2 set _prolog flag base url C Users Jan Burse Desktop VSS 2 sys_add file extension text dcg text prolog Yes absolute file name my folder my file X X file C Users Jan Burse Desktop my folder my file dcg Paths should not use a system specific directory separator but always use the forward slash For convenience paths have an automatic prefixing of a schema Paths starting with a double slash are prefixed by the http schema Paths starting with a single slash are prefixed by the file schema Drive letters are not considered schema If the path is wrapped into a compound and if the functor of the compound is either library 1 foreign 1 or verbatim 1 then the path is looked up in the class path The class path can be updated and queried by the predicates sys _add_path 1 and sys_current_path 1 In these cases the prefixes of the package 1 and use_package 1 command are also used Write or append access resolution lt path gt resolve lt path gt in base Read access resolution library lt path gt lookup resource lt path gt in class path foreign lt path gt Hookupmclasism path mel neacsleas Sao ciel verbatim lt path gt like library lt path gt or take as is lt path gt resolve lt path gt in scope or base The predicates absolute_file_name

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