/* $Id: chr_swi.pl,v 1.1 2005-10-28 17:41:30 vsc Exp $ Part of CHR (Constraint Handling Rules) Author: Tom Schrijvers and Jan Wielemaker E-mail: Tom.Schrijvers@cs.kuleuven.ac.be WWW: http://www.swi-prolog.org Copyright (C): 2003-2004, K.U. Leuven This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module(chr, [ op( 700, xfx, ::), op(1180, xfx, ==>), op(1180, xfx, <=>), op(1150, fx, constraints), op(1150, fx, handler), op(1150, fx, rules), op(1100, xfx, \), op(1200, xfx, @), op(1190, xfx, pragma), op( 500, yfx, #), op(1150, fx, chr_type), op(1130, xfx, --->), op(1150, fx, (?)), chr_show_store/1, % +Module find_chr_constraint/1, % +Pattern chr_trace/0, chr_notrace/0, chr_leash/1 % +Ports ]). :- set_prolog_flag(generate_debug_info, false). :- multifile user:file_search_path/2. :- dynamic user:file_search_path/2. :- dynamic chr_translated_program/1. user:file_search_path(chr, library(chr)). :- use_module(chr(chr_translate)). :- use_module(chr(chr_runtime)). :- use_module(chr(chr_debug)). :- use_module(chr(chr_messages)). :- use_module(library(gensym)). :- use_module(chr(chr_hashtable_store)). :- dynamic chr_term/2. % File, Term % chr_expandable(+Term) % % Succeeds if Term is a rule that must be handled by the CHR % compiler. Ideally CHR definitions should be between % % :- constraints ... % ... % :- end_constraints. % % As they are not we have to use some heuristics. We assume any % file is a CHR after we've seen :- constraints ... or if the file % is named *.chr chr_expandable((:- constraints _)). chr_expandable((constraints _)). chr_expandable((:- chr_type _)). chr_expandable((chr_type _)). chr_expandable((handler _)) :- is_chr_file. chr_expandable((rules _)) :- is_chr_file. chr_expandable((_ <=> _)) :- is_chr_file. chr_expandable((_ @ _)) :- is_chr_file. chr_expandable((_ ==> _)) :- is_chr_file. chr_expandable((_ pragma _)) :- is_chr_file. chr_expandable(option(_, _)) :- is_chr_file. is_chr_file :- true. /* source_location(File, _Line), ( chr_term(File, _) -> true ; file_name_extension(_, chr, File) ). */ % chr_expand(+Term, -Expansion) % % Extract CHR declarations and rules from the file and run the % CHR compiler when reaching end-of-file. chr_expand(Term, []) :- chr_expandable(Term), !, source_location(File, _Line), assert(chr_term(File, Term)). chr_expand(end_of_file, [ (:- use_module(chr(chr_runtime))), (:- style_check(-(discontiguous))), % no need to restore; file ends (:- set_prolog_flag(generate_debug_info, false)) | Program ]) :- is_chr_file, source_location(File, _Line), findall(T, retract(chr_term(File, T)), CHR0), CHR0 \== [], % length(CHR0, NDecls), % format('Translating ~w declarations~n', [NDecls]), prolog_load_context(module, Module), ( Module == user -> ( memberchk(handler(Handler), CHR0) -> true ; gensym(chr_handler, Handler) ) ; Handler = Module ), add_debug_decl(CHR0, CHR1), add_optimise_decl(CHR1, CHR), call_chr_translate(File, [ (:- module(Handler, [])) | CHR ], Program0), delete_header(Program0, Program). delete_header([(:- module(_,_))|T0], T) :- !, delete_header(T0, T). delete_header(L, L). add_debug_decl(CHR, CHR) :- memberchk(option(debug, _), CHR), !. add_debug_decl(CHR, [option(debug, Debug)|CHR]) :- ( current_prolog_flag(generate_debug_info, true) -> Debug = on ; Debug = off ). add_optimise_decl(CHR, CHR) :- memberchk(option(optimize, _), CHR), !. add_optimise_decl(CHR, [option(optimize, full)|CHR]) :- current_prolog_flag(optimize, true), !. add_optimise_decl(CHR, CHR). % call_chr_translate(+File, +In, -Out) % % The entire chr_translate/2 translation may fail, in which we'd % better issue a warning rather than simply ignoring the CHR % declarations. call_chr_translate(_, In, _Out) :- ( chr_translate(In, Out0) -> nb_setval(chr_translated_program,Out0), fail ). call_chr_translate(_, _In, Out) :- nb_current(chr_translated_program,Out),!,nb_delete(chr_translated_program). call_chr_translate(File, _, []) :- print_message(error, chr(compilation_failed(File))). /******************************* * SYNCHRONISE TRACER * *******************************/ :- multifile user:message_hook/3, chr:debug_event/2, chr:debug_interact/3. :- dynamic user:message_hook/3. user:message_hook(trace_mode(OnOff), _, _) :- ( OnOff == on -> chr_trace ; chr_notrace ), fail. % backtrack to other handlers % chr:debug_event(+State, +Event) % % Hook into the CHR debugger. At this moment we will discard CHR % events if we are in a Prolog `skip' and we ignore the chr:debug_event(_State, _Event) :- tracing, % are we tracing? prolog_skip_level(Skip, Skip), Skip \== very_deep, prolog_current_frame(Me), prolog_frame_attribute(Me, level, Level), Level > Skip, !. % chr:debug_interact(+Event, +Depth, -Command) % % Hook into the CHR debugger to display Event and ask for the next % command to execute. This definition causes the normal Prolog % debugger to be used for the standard ports. chr:debug_interact(Event, _Depth, creep) :- prolog_event(Event), tracing, !. prolog_event(call(_)). prolog_event(exit(_)). prolog_event(fail(_)). /******************************* * MESSAGES * *******************************/ :- multifile prolog:message/3. prolog:message(chr(CHR)) --> chr_message(CHR). /******************************* * TOPLEVEL PRINTING * *******************************/ :- set_prolog_flag(chr_toplevel_show_store,true). :- multifile chr:'$chr_module'/1. prolog:message(query(YesNo)) --> !, ['~@'-[chr:print_all_stores]], '$messages':prolog_message(query(YesNo)). prolog:message(query(YesNo,Bindings)) --> !, ['~@'-[chr:print_all_stores]], '$messages':prolog_message(query(YesNo,Bindings)). print_all_stores :- ( current_prolog_flag(chr_toplevel_show_store,true), catch(nb_getval(chr_global, _), _, fail), chr:'$chr_module'(Mod), chr_show_store(Mod), fail ; true ). /******************************* * MUST BE LAST! * *******************************/ :- multifile user:term_expansion/2. :- dynamic user:term_expansion/2. user:term_expansion(In, Out) :- chr_expand(In, Out).