/* $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).