1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (c) 2006-2016, University of Amsterdam 7 Vu University Amsterdam 8 All rights reserved. 9 10 Redistribution and use in source and binary forms, with or without 11 modification, are permitted provided that the following conditions 12 are met: 13 14 1. Redistributions of source code must retain the above copyright 15 notice, this list of conditions and the following disclaimer. 16 17 2. Redistributions in binary form must reproduce the above copyright 18 notice, this list of conditions and the following disclaimer in 19 the documentation and/or other materials provided with the 20 distribution. 21 22 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 23 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 24 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 25 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 26 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 27 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 28 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 29 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 30 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 32 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 POSSIBILITY OF SUCH DAMAGE. 34*/ 35 36:- module(prolog_source, 37 [ prolog_read_source_term/4, % +Stream, -Term, -Expanded, +Options 38 read_source_term_at_location/3, %Stream, -Term, +Options 39 prolog_open_source/2, % +Source, -Stream 40 prolog_close_source/1, % +Stream 41 prolog_canonical_source/2, % +Spec, -Id 42 43 load_quasi_quotation_syntax/2, % :Path, +Syntax 44 45 file_name_on_path/2, % +File, -PathSpec 46 file_alias_path/2, % ?Alias, ?Dir 47 path_segments_atom/2, % ?Segments, ?Atom 48 directory_source_files/3 % +Dir, -Files, +Options 49 ]). 50:- use_module(operators). 51:- use_module(lists). 52:- use_module(debug). 53:- use_module(option). 54:- use_module(error). 55:- use_module(apply).
80:- thread_local 81 open_source/2, % Stream, State 82 mode/2. % Stream, Data 83 84:- multifile 85 requires_library/2, 86 prolog:xref_source_identifier/2, % +Source, -Id 87 prolog:xref_source_time/2, % +Source, -Modified 88 prolog:xref_open_source/2, % +SourceId, -Stream 89 prolog:xref_close_source/2, % +SourceId, -Stream 90 prolog:alternate_syntax/4, % Syntax, +Module, -Setup, -Restore 91 prolog:quasi_quotation_syntax/2. % Syntax, Library 92 93 94:- predicate_options(prolog_read_source_term/4, 4, 95 [ pass_to(system:read_clause/3, 3) 96 ]). 97:- predicate_options(read_source_term_at_location/3, 3, 98 [ line(integer), 99 offset(integer), 100 module(atom), 101 operators(list), 102 error(-any), 103 pass_to(system:read_term/3, 3) 104 ]). 105:- predicate_options(directory_source_files/3, 3, 106 [ recursive(boolean), 107 if(oneof([true,loaded])), 108 pass_to(system:absolute_file_name/3,3) 109 ]). 110 111 112 /******************************* 113 * READING * 114 *******************************/
This predicate is intended to read the file from the start. It tracks directives to update its notion of the currently effective syntax (e.g., declared operators).
130prolog_read_source_term(In, Term, Expanded, Options) :- 131 maplist(read_clause_option, Options), 132 !, 133 select_option(subterm_positions(TermPos), Options, 134 RestOptions, TermPos), 135 read_clause(In, Term, 136 [ subterm_positions(TermPos) 137 | RestOptions 138 ]), 139 expand(Term, TermPos, In, Expanded), 140 '$current_source_module'(M), 141 update_state(Term, Expanded, M). 142prolog_read_source_term(In, Term, Expanded, Options) :- 143 '$current_source_module'(M), 144 select_option(syntax_errors(SE), Options, RestOptions0, dec10), 145 select_option(subterm_positions(TermPos), RestOptions0, 146 RestOptions, TermPos), 147 ( style_check(?(singleton)) 148 -> FinalOptions = [ singletons(warning) | RestOptions ] 149 ; FinalOptions = RestOptions 150 ), 151 read_term(In, Term, 152 [ module(M), 153 syntax_errors(SE), 154 subterm_positions(TermPos) 155 | FinalOptions 156 ]), 157 expand(Term, TermPos, In, Expanded), 158 update_state(Term, Expanded, M). 159 160read_clause_option(syntax_errors(_)). 161read_clause_option(term_position(_)). 162read_clause_option(process_comment(_)). 163read_clause_option(comments(_)). 164 165:- public 166 expand/3. % Used by Prolog colour 167 168expand(Term, In, Exp) :- 169 expand(Term, _, In, Exp). 170 171expand(Var, _, _, Var) :- 172 var(Var), 173 !. 174expand(Term, _, _, Term) :- 175 no_expand(Term), 176 !. 177expand(Term, _, _, _) :- 178 requires_library(Term, Lib), 179 ensure_loaded(user:Lib), 180 fail. 181expand(Term, _, In, Term) :- 182 chr_expandable(Term, In), 183 !. 184expand(Term, Pos, _, Expanded) :- 185 expand_term(Term, Pos, Expanded, _). 186 187no_expand((:- if(_))). 188no_expand((:- elif(_))). 189no_expand((:- else)). 190no_expand((:- endif)). 191no_expand((:- require(_))). 192 193chr_expandable((:- chr_constraint(_)), In) :- 194 add_mode(In, chr). 195chr_expandable((handler(_)), In) :- 196 mode(In, chr). 197chr_expandable((rules(_)), In) :- 198 mode(In, chr). 199chr_expandable(<=>(_, _), In) :- 200 mode(In, chr). 201chr_expandable(@(_, _), In) :- 202 mode(In, chr). 203chr_expandable(==>(_, _), In) :- 204 mode(In, chr). 205chr_expandable(pragma(_, _), In) :- 206 mode(In, chr). 207chr_expandable(option(_, _), In) :- 208 mode(In, chr). 209 210add_mode(Stream, Mode) :- 211 mode(Stream, Mode), 212 !. 213add_mode(Stream, Mode) :- 214 asserta(mode(Stream, Mode)).
220requires_library((:- emacs_begin_mode(_,_,_,_,_)), library(emacs_extend)). 221requires_library((:- draw_begin_shape(_,_,_,_)), library(pcedraw)). 222requires_library((:- use_module(library(pce))), library(pce)). 223requires_library((:- pce_begin_class(_,_)), library(pce)). 224requires_library((:- pce_begin_class(_,_,_)), library(pce)).
230:- multifile 231 pce_expansion:push_compile_operators/1, 232 pce_expansion:pop_compile_operators/0. 233 234update_state(Raw, _, _) :- 235 Raw == (:- pce_end_class), 236 !, 237 ignore(pce_expansion:pop_compile_operators). 238update_state(Raw, _, SM) :- 239 subsumes_term((:- pce_extend_class(_)), Raw), 240 !, 241 pce_expansion:push_compile_operators(SM). 242update_state(_Raw, Expanded, M) :- 243 update_state(Expanded, M). 244 245update_state(Var, _) :- 246 var(Var), 247 !. 248update_state([], _) :- 249 !. 250update_state([H|T], M) :- 251 !, 252 update_state(H, M), 253 update_state(T, M). 254update_state((:- Directive), M) :- 255 nonvar(Directive), 256 !, 257 catch(update_directive(Directive, M), _, true). 258update_state((?- Directive), M) :- 259 !, 260 update_state((:- Directive), M). 261update_state(_, _). 262 263update_directive(module(Module, Public), _) :- 264 atom(Module), 265 !, 266 '$set_source_module'(Module), 267 maplist(import_syntax(_,Module, _), Public). 268update_directive(M:op(P,T,N), SM) :- 269 atom(M), 270 ground(op(P,T,N)), 271 !, 272 update_directive(op(P,T,N), SM). 273update_directive(op(P,T,N), SM) :- 274 ground(op(P,T,N)), 275 !, 276 strip_module(SM:N, M, PN), 277 push_op(P,T,M:PN). 278update_directive(style_check(Style), _) :- 279 ground(Style), 280 style_check(Style), 281 !. 282update_directive(use_module(Spec), SM) :- 283 ground(Spec), 284 catch(module_decl(Spec, Path, Public), _, fail), 285 !, 286 maplist(import_syntax(Path, SM, _), Public). 287update_directive(use_module(Spec, Imports), SM) :- 288 ground(Spec), 289 is_list(Imports), 290 catch(module_decl(Spec, Path, Public), _, fail), 291 !, 292 maplist(import_syntax(Path, SM, Imports), Public). 293update_directive(pce_begin_class_definition(_,_,_,_), SM) :- 294 pce_expansion:push_compile_operators(SM), 295 !. 296update_directive(_, _).
303import_syntax(_, _, _, Var) :- 304 var(Var), 305 !. 306import_syntax(_, M, Imports, Op) :- 307 Op = op(_,_,_), 308 \+ \+ member(Op, Imports), 309 !, 310 update_directive(Op, M). 311import_syntax(Path, SM, Imports, Syntax/4) :- 312 \+ \+ member(Syntax/4, Imports), 313 load_quasi_quotation_syntax(SM:Path, Syntax), 314 !. 315import_syntax(_,_,_, _).
332load_quasi_quotation_syntax(SM:Path, Syntax) :- 333 atom(Path), atom(Syntax), 334 source_file_property(Path, module(M)), 335 functor(ST, Syntax, 4), 336 predicate_property(M:ST, quasi_quotation_syntax), 337 !, 338 use_module(SM:Path, [Syntax/4]). 339load_quasi_quotation_syntax(SM:Path, Syntax) :- 340 atom(Path), atom(Syntax), 341 prolog:quasi_quotation_syntax(Syntax, Spec), 342 absolute_file_name(Spec, Path2, 343 [ file_type(prolog), 344 file_errors(fail), 345 access(read) 346 ]), 347 Path == Path2, 348 !, 349 use_module(SM:Path, [Syntax/4]).
357module_decl(Spec, Path, Decl) :- 358 absolute_file_name(Spec, Path, 359 [ file_type(prolog), 360 file_errors(fail), 361 access(read) 362 ]), 363 setup_call_cleanup( 364 prolog_open_source(Path, In), 365 read_module_decl(In, Decl), 366 prolog_close_source(In)). 367 368read_module_decl(In, Decl) :- 369 read(In, Term0), 370 read_module_decl(Term0, In, Decl). 371 372read_module_decl(Term, _In, Decl) :- 373 subsumes_term((:- module(_, Decl)), Term), 374 !, 375 Term = (:- module(_, Decl)). 376read_module_decl(Term, In, Decl) :- 377 subsumes_term((:- encoding(_)), Term), 378 !, 379 Term = (:- encoding(Enc)), 380 set_stream(In, encoding(Enc)), 381 read(In, Term2), 382 read_module_decl(Term2, In, Decl).
This predicate has two ways to find the right syntax. If the file is loaded, it can be passed the module using the module option. This deals with module files that define the used operators globally for the file. Second, there is a hook alternate_syntax/4 that can be used to temporary redefine the syntax.
The options below are processed in addition to the options of
read_term/3. Note that the line and offset options are
mutually exclusive.
det).426:- thread_local 427 last_syntax_error/2. % location, message 428 429read_source_term_at_location(Stream, Term, Options) :- 430 retractall(last_syntax_error(_,_)), 431 seek_to_start(Stream, Options), 432 stream_property(Stream, position(Here)), 433 '$current_source_module'(DefModule), 434 option(module(Module), Options, DefModule), 435 option(operators(Ops), Options, []), 436 alternate_syntax(Syntax, Module, Setup, Restore), 437 set_stream_position(Stream, Here), 438 debug(read, 'Trying with syntax ~w', [Syntax]), 439 push_operators(Module:Ops), 440 call(Setup), 441 Error = error(Formal,_), % do not catch timeout, etc. 442 setup_call_cleanup( 443 asserta(user:thread_message_hook(_,_,_), Ref), % silence messages 444 catch(qq_read_term(Stream, Term0, 445 [ module(Module) 446 | Options 447 ]), 448 Error, 449 true), 450 erase(Ref)), 451 call(Restore), 452 pop_operators, 453 ( var(Formal) 454 -> !, Term = Term0 455 ; assert_error(Error, Options), 456 fail 457 ). 458read_source_term_at_location(_, _, Options) :- 459 option(error(Error), Options), 460 !, 461 setof(CharNo:Msg, retract(last_syntax_error(CharNo, Msg)), Pairs), 462 last(Pairs, Error). 463 464assert_error(Error, Options) :- 465 option(error(_), Options), 466 !, 467 ( ( Error = error(syntax_error(Id), 468 stream(_S1, _Line1, _LinePos1, CharNo)) 469 ; Error = error(syntax_error(Id), 470 file(_S2, _Line2, _LinePos2, CharNo)) 471 ) 472 -> message_to_string(error(syntax_error(Id), _), Msg), 473 assertz(last_syntax_error(CharNo, Msg)) 474 ; debug(read, 'Error: ~q', [Error]), 475 throw(Error) 476 ). 477assert_error(_, _).
Calls the hook alternate_syntax/4 with the same signature to allow for user-defined extensions.
493alternate_syntax(prolog, _, true, true). 494alternate_syntax(Syntax, M, Setup, Restore) :- 495 prolog:alternate_syntax(Syntax, M, Setup, Restore).
502seek_to_start(Stream, Options) :- 503 option(line(Line), Options), 504 !, 505 seek(Stream, 0, bof, _), 506 seek_to_line(Stream, Line). 507seek_to_start(Stream, Options) :- 508 option(offset(Start), Options), 509 !, 510 seek(Stream, Start, bof, _). 511seek_to_start(_, _).
517seek_to_line(Fd, N) :- 518 N > 1, 519 !, 520 skip(Fd, 10), 521 NN is N - 1, 522 seek_to_line(Fd, NN). 523seek_to_line(_, _). 524 525 526 /******************************* 527 * QUASI QUOTATIONS * 528 *******************************/
536qq_read_term(Stream, Term, Options) :- 537 select(syntax_errors(ErrorMode), Options, Options1), 538 ErrorMode \== error, 539 !, 540 ( ErrorMode == dec10 541 -> repeat, 542 qq_read_syntax_ex(Stream, Term, Options1, Error), 543 ( var(Error) 544 -> ! 545 ; print_message(error, Error), 546 fail 547 ) 548 ; qq_read_syntax_ex(Stream, Term, Options1, Error), 549 ( ErrorMode == fail 550 -> print_message(error, Error), 551 fail 552 ; ErrorMode == quiet 553 -> fail 554 ; domain_error(syntax_errors, ErrorMode) 555 ) 556 ). 557qq_read_term(Stream, Term, Options) :- 558 qq_read_term_ex(Stream, Term, Options). 559 560qq_read_syntax_ex(Stream, Term, Options, Error) :- 561 catch(qq_read_term_ex(Stream, Term, Options), 562 error(syntax_error(Syntax), Context), 563 Error = error(Syntax, Context)). 564 565qq_read_term_ex(Stream, Term, Options) :- 566 stream_property(Stream, position(Here)), 567 catch(read_term(Stream, Term, Options), 568 error(syntax_error(unknown_quasi_quotation_syntax(Syntax, Module)), Context), 569 load_qq_and_retry(Here, Syntax, Module, Context, Stream, Term, Options)). 570 571load_qq_and_retry(Here, Syntax, Module, _, Stream, Term, Options) :- 572 set_stream_position(Stream, Here), 573 prolog:quasi_quotation_syntax(Syntax, Library), 574 !, 575 use_module(Module:Library, [Syntax/4]), 576 read_term(Stream, Term, Options). 577load_qq_and_retry(_Pos, Syntax, Module, Context, _Stream, _Term, _Options) :- 578 print_message(warning, quasi_quotation(undeclared, Syntax)), 579 throw(error(syntax_error(unknown_quasi_quotation_syntax(Syntax, Module)), Context)).
This multifile hook is used by library(prolog_source) to load
quasi quotation handlers on demand.
590prologquasi_quotation_syntax(html, library(http/html_write)). 591prologquasi_quotation_syntax(javascript, library(http/js_write)). 592 593 594 /******************************* 595 * SOURCES * 596 *******************************/
process_source(Src) :-
prolog_open_source(Src, In),
call_cleanup(process(Src), prolog_close_source(In)).
613prolog_open_source(Src, Fd) :- 614 '$push_input_context'(source), 615 catch(( prolog:xref_open_source(Src, Fd) 616 -> Hooked = true 617 ; open(Src, read, Fd), 618 Hooked = false 619 ), E, 620 ( '$pop_input_context', 621 throw(E) 622 )), 623 skip_hashbang(Fd), 624 push_operators([]), 625 '$current_source_module'(SM), 626 '$save_lex_state'(LexState, []), 627 asserta(open_source(Fd, state(Hooked, Src, LexState, SM))). 628 629skip_hashbang(Fd) :- 630 catch(( peek_char(Fd, #) % Deal with #! script 631 -> skip(Fd, 10) 632 ; true 633 ), E, 634 ( close(Fd, [force(true)]), 635 '$pop_input_context', 636 throw(E) 637 )).
expand_term(end_of_file, _) to allow expansion
modules to clean-up.655prolog_close_source(In) :- 656 call_cleanup( 657 restore_source_context(In, Hooked, Src), 658 close_source(Hooked, Src, In)). 659 660close_source(true, Src, In) :- 661 catch(prolog:xref_close_source(Src, In), _, false), 662 !, 663 '$pop_input_context'. 664close_source(_, _Src, In) :- 665 close(In, [force(true)]), 666 '$pop_input_context'. 667 668restore_source_context(In, Hooked, Src) :- 669 ( at_end_of_stream(In) 670 -> true 671 ; ignore(catch(expand(end_of_file, _, In, _), _, true)) 672 ), 673 pop_operators, 674 retractall(mode(In, _)), 675 ( retract(open_source(In, state(Hooked, Src, LexState, SM))) 676 -> '$restore_lex_state'(LexState), 677 '$set_source_module'(SM) 678 ; assertion(fail) 679 ).
force(true) is used.694prolog_canonical_source(Source, Src) :- 695 var(Source), 696 !, 697 Src = Source. 698prolog_canonical_source(User, user) :- 699 User == user, 700 !. 701prolog_canonical_source(Src, Id) :- % Call hook 702 prolog:xref_source_identifier(Src, Id), 703 !. 704prolog_canonical_source(Source, Src) :- 705 source_file(Source), 706 !, 707 Src = Source. 708prolog_canonical_source(Source, Src) :- 709 absolute_file_name(Source, Src, 710 [ file_type(prolog), 711 access(read), 712 file_errors(fail) 713 ]), 714 !.
722file_name_on_path(Path, ShortId) :-
723 ( file_alias_path(Alias, Dir),
724 atom_concat(Dir, Local, Path)
725 -> ( Alias == '.'
726 -> ShortId = Local
727 ; file_name_extension(Base, pl, Local)
728 -> ShortId =.. [Alias, Base]
729 ; ShortId =.. [Alias, Local]
730 )
731 ; ShortId = Path
732 ).740:- dynamic 741 alias_cache/2. 742 743file_alias_path(Alias, Dir) :- 744 ( alias_cache(_, _) 745 -> true 746 ; build_alias_cache 747 ), 748 ( nonvar(Dir) 749 -> ensure_slash(Dir, DirSlash), 750 alias_cache(Alias, DirSlash) 751 ; alias_cache(Alias, Dir) 752 ). 753 754build_alias_cache :- 755 findall(t(DirLen, AliasLen, Alias, Dir), 756 search_path(Alias, Dir, AliasLen, DirLen), Ts), 757 sort(0, >, Ts, List), 758 forall(member(t(_, _, Alias, Dir), List), 759 assert(alias_cache(Alias, Dir))). 760 761search_path('.', Here, 999, DirLen) :- 762 working_directory(Here0, Here0), 763 ensure_slash(Here0, Here), 764 atom_length(Here, DirLen). 765search_path(Alias, Dir, AliasLen, DirLen) :- 766 user:file_search_path(Alias, _), 767 Alias \== autoload, 768 Spec =.. [Alias,'.'], 769 atom_length(Alias, AliasLen0), 770 AliasLen is 1000 - AliasLen0, % must do reverse sort 771 absolute_file_name(Spec, Dir0, 772 [ file_type(directory), 773 access(read), 774 solutions(all), 775 file_errors(fail) 776 ]), 777 ensure_slash(Dir0, Dir), 778 atom_length(Dir, DirLen). 779 780ensure_slash(Dir, Dir) :- 781 sub_atom(Dir, _, _, 0, /), 782 !. 783ensure_slash(Dir0, Dir) :- 784 atom_concat(Dir0, /, Dir).
?- path_segments_atom(a/b/c, X). X = 'a/b/c'. ?- path_segments_atom(S, 'a/b/c'), display(S). /(/(a,b),c) S = a/b/c.
This predicate is part of the Prolog source library because SWI-Prolog allows writing paths as /-nested terms and source-code analysis programs often need this.
805path_segments_atom(Segments, Atom) :- 806 var(Atom), 807 !, 808 ( atomic(Segments) 809 -> Atom = Segments 810 ; segments_to_list(Segments, List, []) 811 -> atomic_list_concat(List, /, Atom) 812 ; throw(error(type_error(file_path, Segments), _)) 813 ). 814path_segments_atom(Segments, Atom) :- 815 atomic_list_concat(List, /, Atom), 816 parts_to_path(List, Segments). 817 818segments_to_list(Var, _, _) :- 819 var(Var), !, fail. 820segments_to_list(A/B, H, T) :- 821 segments_to_list(A, H, T0), 822 segments_to_list(B, T0, T). 823segments_to_list(A, [A|T], T) :- 824 atomic(A). 825 826parts_to_path([One], One) :- !. 827parts_to_path(List, More/T) :- 828 ( append(H, [T], List) 829 -> parts_to_path(H, More) 830 ).
true (default false), recurse into subdirectoriestrue (default loaded), only report loaded files.
Other options are passed to absolute_file_name/3, unless
loaded(true) is passed.
845directory_source_files(Dir, SrcFiles, Options) :- 846 option(if(loaded), Options, loaded), 847 !, 848 absolute_file_name(Dir, AbsDir, [file_type(directory), access(read)]), 849 ( option(recursive(true), Options) 850 -> ensure_slash(AbsDir, Prefix), 851 findall(F, ( source_file(F), 852 sub_atom(F, 0, _, _, Prefix) 853 ), 854 SrcFiles) 855 ; findall(F, ( source_file(F), 856 file_directory_name(F, AbsDir) 857 ), 858 SrcFiles) 859 ). 860directory_source_files(Dir, SrcFiles, Options) :- 861 absolute_file_name(Dir, AbsDir, [file_type(directory), access(read)]), 862 directory_files(AbsDir, Files), 863 phrase(src_files(Files, AbsDir, Options), SrcFiles). 864 865src_files([], _, _) --> 866 []. 867src_files([H|T], Dir, Options) --> 868 { file_name_extension(_, Ext, H), 869 user:prolog_file_type(Ext, prolog), 870 \+ user:prolog_file_type(Ext, qlf), 871 dir_file_path(Dir, H, File0), 872 absolute_file_name(File0, File, 873 [ file_errors(fail) 874 | Options 875 ]) 876 }, 877 !, 878 [File], 879 src_files(T, Dir, Options). 880src_files([H|T], Dir, Options) --> 881 { \+ special(H), 882 option(recursive(true), Options), 883 dir_file_path(Dir, H, SubDir), 884 exists_directory(SubDir), 885 !, 886 catch(directory_files(SubDir, Files), _, fail) 887 }, 888 !, 889 src_files(Files, SubDir, Options), 890 src_files(T, Dir, Options). 891src_files([_|T], Dir, Options) --> 892 src_files(T, Dir, Options). 893 894special(.). 895special(..). 896 897% avoid dependency on library(filesex), which also pulls a foreign 898% dependency. 899dir_file_path(Dir, File, Path) :- 900 ( sub_atom(Dir, _, _, 0, /) 901 -> atom_concat(Dir, File, Path) 902 ; atom_concat(Dir, /, TheDir), 903 atom_concat(TheDir, File, Path) 904 ). 905 906 907 908 /******************************* 909 * MESSAGES * 910 *******************************/ 911 912:- multifile 913 prolog:message//1. 914 915prologmessage(quasi_quotation(undeclared, Syntax)) --> 916 [ 'Undeclared quasi quotation syntax: ~w'-[Syntax], nl, 917 'Autoloading can be defined using prolog:quasi_quotation_syntax/2' 918 ]
Examine Prolog source-files
This module provides predicates to open, close and read terms from Prolog source-files. This may seem easy, but there are a couple of problems that must be taken care of.
This module concentrates these issues in a single library. Intended users of the library are:
prolog_xref.plprolog_clause.plprolog_colour.pl*/