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yap-6.3/pl/control.yap
2009-11-20 00:33:14 +00:00

300 lines
7.8 KiB
Prolog

/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: control.yap *
* Last rev: 20/08/09 *
* mods: *
* comments: control predicates available in yap *
* *
*************************************************************************/
once(G) :- '$execute'(G), !.
forall(Cond, Action) :- \+((Cond, \+(Action))).
ignore(Goal) :- (Goal->true;true).
if(X,Y,Z) :-
yap_hacks:env_choice_point(CP0),
(
CP is '$last_choice_pt',
'$call'(X,CP,if(X,Y,Z),M),
'$execute'(X),
'$clean_ifcp'(CP),
'$call'(Y,CP,if(X,Y,Z),M)
;
'$call'(Z,CP,if(X,Y,Z),M)
).
call(X,A) :- '$execute'(X,A).
call(X,A1,A2) :- '$execute'(X,A1,A2).
call(X,A1,A2,A3) :- '$execute'(X,A1,A2,A3).
call(X,A1,A2,A3,A4) :- '$execute'(X,A1,A2,A3,A4).
call(X,A1,A2,A3,A4,A5) :- '$execute'(X,A1,A2,A3,A4,A5).
call(X,A1,A2,A3,A4,A5,A6) :- '$execute'(X,A1,A2,A3,A4,A5,A6).
call(X,A1,A2,A3,A4,A5,A6,A7) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7).
call(X,A1,A2,A3,A4,A5,A6,A7,A8) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8).
call(X,A1,A2,A3,A4,A5,A6,A7,A8,A9) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8,A9).
call(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10).
call(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11) :- '$execute'(X,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11).
call_cleanup(Goal, Cleanup) :-
setup_call_catcher_cleanup(true, Goal, _Catcher, Cleanup).
call_cleanup(Goal, Catcher, Cleanup) :-
setup_call_catcher_cleanup(true, Goal, Catcher, Cleanup).
setup_call_cleanup(Setup, Goal, Cleanup) :-
setup_call_catcher_cleanup(Setup, Goal, Catcher, Cleanup).
setup_call_catcher_cleanup(Setup, Goal, Catcher, Cleanup) :-
yap_hacks:disable_interrupts,
'$do_setup'(Setup),
catch('$safe_call_cleanup'(Goal,Cleanup,Catcher,Exception),
Exception,
'$cleanup_exception'(Exception,Catcher,Cleanup)).
% this is simple, do nothing
'$do_setup'(A:true) :- atom(A), !.
% this is tricky: please don't forget that interrupts are disabled at this point
% and that they will only be enabled after setting up Cleanup
'$do_setup'(Setup) :-
(
'$execute'(Setup),
% we don't need to care about enabling interrupts
!
;
% reenable interrupts if Setup failed
yap_hacks:enable_interrupts,
fail
).
'$cleanup_exception'(Exception, exception(Exception), Cleanup) :- !,
% whatever happens, let exception go through
catch('$clean_call'(_,Cleanup),_,true),
throw(Exception).
'$cleanup_exception'(Exception, _, _) :-
throw(Exception).
'$safe_call_cleanup'(Goal, Cleanup, Catcher, Exception) :-
yap_hacks:current_choice_point(MyCP1),
'$freeze_goal'(Catcher, '$clean_call'(Exception, Cleanup)),
yap_hacks:trail_suspension_marker(Catcher),
(
yap_hacks:enable_interrupts,
yap_hacks:current_choice_point(CP0),
'$execute'(Goal),
% ensure environment for delayed variables in Goal
'$true',
yap_hacks:current_choice_point(CPF),
(
CP0 =:= CPF
->
Catcher = exit,
!
;
true
)
;
Catcher = fail,
fail
).
'$holds_true'.
% The first argument is used by JumpEnv to verify if a throw
% is going to be handled by the cleanup catcher. If it is so,
% clean_call will not be called from JumpToEnv.
'$clean_call'(_,Cleanup) :-
'$execute'(Cleanup), !.
'$clean_call'(_,_).
%%% The unknown predicate,
% informs about what the user wants to be done when
% there are no clauses for a certain predicate */
unknown(V0,V) :-
'$current_module'(M),
'$unknown'(V0,V,M).
% query mode
'$unknown'(V0,V,_) :- var(V), !,
'$ask_unknown_flag'(V),
V = V0.
% handle modules.
'$unknown'(V0,Mod:Handler,_) :-
'$unknown'(V0,Handler,Mod).
% check if we have one we like.
'$unknown'(_,New,Mod) :-
'$valid_unknown_handler'(New,Mod), fail.
% clean up previous unknown predicate handlers
'$unknown'(Old,New,Mod) :-
recorded('$unknown','$unknown'(_,MyOld),Ref), !,
erase(Ref),
'$cleanup_unknown_handler'(MyOld,Old),
'$new_unknown'(New, Mod).
% store the new one.
'$unknown'(fail,New,Mod) :-
'$new_unknown'(New, Mod).
'$valid_unknown_handler'(V,_) :-
var(V), !,
'$do_error'(instantiation_error,yap_flag(unknown,V)).
'$valid_unknown_handler'(fail,_) :- !.
'$valid_unknown_handler'(error,_) :- !.
'$valid_unknown_handler'(warning,_) :- !.
'$valid_unknown_handler'(S,M) :-
functor(S,_,1),
arg(1,S,A),
var(A),
\+ '$undefined'(S,M),
!.
'$valid_unknown_handler'(S,_) :-
'$do_error'(domain_error(flag_value,unknown+S),yap_flag(unknown,S)).
'$ask_unknown_flag'(Old) :-
recorded('$unknown','$unknown'(_,MyOld),_), !,
'$cleanup_unknown_handler'(MyOld,Old).
'$ask_unknown_flag'(fail).
'$cleanup_unknown_handler'('$unknown_error'(_),error) :- !.
'$cleanup_unknown_handler'('$unknown_warning'(_),warning) :- !.
'$cleanup_unknown_handler'(Handler, Handler).
'$new_unknown'(fail,_) :- !.
'$new_unknown'(error,_) :- !,
recorda('$unknown','$unknown'(P,'$unknown_error'(P)),_).
'$new_unknown'(warning,_) :- !,
recorda('$unknown','$unknown'(P,'$unknown_warning'(P)),_).
'$new_unknown'(X,M) :-
arg(1,X,A),
recorda('$unknown','$unknown'(A,M:X),_).
'$unknown_error'(Mod:Goal) :-
functor(Goal,Name,Arity),
'$program_continuation'(PMod,PName,PAr),
'$do_error'(existence_error(procedure,Name/Arity),context(Mod:Goal,PMod:PName/PAr)).
'$unknown_warning'(Mod:Goal) :-
functor(Goal,Name,Arity),
'$program_continuation'(PMod,PName,PAr),
print_message(error,error(existence_error(procedure,Name/Arity), context(Mod:Goal,PMod:PName/PAr))),
fail.
%%% Some "dirty" predicates
% Only efective if yap compiled with -DDEBUG
% this predicate shows the code produced by the compiler
'$show_code' :- '$debug'(0'f). %' just make emacs happy
grow_heap(X) :- '$grow_heap'(X).
grow_stack(X) :- '$grow_stack'(X).
%
% gc() expects to be called from "call". Make sure it has an
% environment to return to.
%
%garbage_collect :- save(dump), '$gc', save(dump2).
garbage_collect :-
'$gc'.
gc :-
yap_flag(gc,on).
nogc :-
yap_flag(gc,off).
garbage_collect_atoms :-
'$atom_gc'.
'$force_environment_for_gc'.
'$good_list_of_character_codes'(V) :- var(V), !.
'$good_list_of_character_codes'([]).
'$good_list_of_character_codes'([X|L]) :-
'$good_character_code'(X),
'$good_list_of_character_codes'(L).
'$good_character_code'(X) :- var(X), !.
'$good_character_code'(X) :- integer(X), X > -2, X < 256.
(initialization) :-
'$initialisation_goals'.
prolog_initialization(G) :- var(G), !,
'$do_error'(instantiation_error,initialization(G)).
prolog_initialization(T) :- callable(T), !,
'$assert_init'(T).
prolog_initialization(T) :-
'$do_error'(type_error(callable,T),initialization(T)).
'$assert_init'(T) :- recordz('$startup_goal',T,_), fail.
'$assert_init'(_).
version :- '$version'.
version(V) :- var(V), !,
'$do_error'(instantiation_error,version(V)).
version(T) :- atom(T), !, '$assert_version'(T).
version(T) :-
'$do_error'(type_error(atom,T),version(T)).
'$assert_version'(T) :- recordz('$version',T,_), fail.
'$assert_version'(_).
'$set_toplevel_hook'(_) :-
recorded('$toplevel_hooks',_,R),
erase(R),
fail.
'$set_toplevel_hook'(H) :-
recorda('$toplevel_hooks',H,_),
fail.
'$set_toplevel_hook'(_).
halt :-
print_message(informational, halt),
'$halt'(0).
halt(X) :-
'$halt'(X).
prolog_current_frame(Env) :-
Env is '$env'.
'$run_atom_goal'(GA) :-
'$current_module'(Module),
atom_codes(GA,Gs0),
'$add_dot_to_atom_goal'(Gs0,Gs),
charsio:open_mem_read_stream(Gs, Stream),
( '$system_catch'(read(Stream, G),Module,_,fail) ->
close(Stream)
;
close(Stream),
fail
),
'$system_catch'('$query'(once(G), []),Module,Error,user:'$Error'(Error)).
'$add_dot_to_atom_goal'([],[0'.]) :- !. %'
'$add_dot_to_atom_goal'([0'.],[0'.]) :- !.
'$add_dot_to_atom_goal'([C|Gs0],[C|Gs]) :-
'$add_dot_to_atom_goal'(Gs0,Gs).