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yap-6.3/pl/attributes.yap
2010-03-22 09:11:27 +00:00

306 lines
7.7 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: atts.yap *
* Last rev: 8/2/88 *
* mods: *
* comments: attribute support for Prolog *
* *
*************************************************************************/
:- module('$attributes', [
project_delayed_goals/2
]).
prolog:get_attr(Var, Mod, Att) :-
functor(AttTerm, Mod, 2),
arg(2, AttTerm, Att),
attributes:get_module_atts(Var, AttTerm).
prolog:put_attr(Var, Mod, Att) :-
functor(AttTerm, Mod, 2),
arg(2, AttTerm, Att),
attributes:put_module_atts(Var, AttTerm).
prolog:del_attr(Var, Mod) :-
functor(AttTerm, Mod, 2),
attributes:del_all_module_atts(Var, AttTerm).
prolog:del_attrs(Var) :-
attributes:del_all_atts(Var).
prolog:get_attrs(AttVar, SWIAtts) :-
attributes:get_all_swi_atts(AttVar,SWIAtts).
prolog:put_attrs(_, []).
prolog:put_attrs(V, Atts) :-
cvt_to_swi_atts(Atts, YapAtts),
attributes:put_att_term(V, YapAtts).
cvt_to_swi_atts([], _).
cvt_to_swi_atts(att(Mod,Attribute,Atts), ModAttribute) :-
ModAttribute =.. [Mod, YapAtts, Attribute],
cvt_to_swi_atts(Atts, YapAtts).
%
% wake_up_goal is called by the system whenever a suspended goal
% resumes.
%
/* The first case may happen if this variable was used for dif.
In this case, we need a way to keep the original
suspended goal around
*/
%'$wake_up_goal'([Module1|Continuation],G) :-
% '$write'(4,vsc_woke:G+[Module1|Continuation]:'
%'), fail.
prolog:'$wake_up_goal'([Module1|Continuation], LG) :-
execute_woken_system_goals(LG),
do_continuation(Continuation, Module1).
%
% in the first two cases restore register immediately and proceed
% to continuation. In the last case take care with modules, but do
% not act as if a meta-call.
%
%
do_continuation('$cut_by'(X), _) :- !,
'$$cut_by'(X).
do_continuation('$restore_regs'(X), _) :- !,
'$restore_regs'(X).
do_continuation('$restore_regs'(X,Y), _) :- !,
'$restore_regs'(X,Y).
do_continuation(Continuation, Module1) :-
execute_continuation(Continuation,Module1).
execute_continuation(Continuation, Module1) :-
'$undefined'(Continuation, Module1), !,
'$undefp'([Module1|Continuation]).
execute_continuation(Continuation, Mod) :-
% do not do meta-expansion nor any fancy stuff.
'$execute0'(Continuation, Mod).
execute_woken_system_goals([]).
execute_woken_system_goals(['$att_do'(V,New)|LG]) :-
execute_woken_system_goals(LG),
call_atts(V,New).
%
% what to do when an attribute gets bound
%
call_atts(V,_) :-
nonvar(V), !.
call_atts(V,_) :-
'$att_bound'(V), !.
call_atts(V,New) :-
attributes:get_all_swi_atts(V,SWIAtts),
(
'$undefined'(woken_att_do(V, New, LGoals, DoNotBind), attributes)
->
LGoals = [],
DoNotBind = false
;
attributes:woken_att_do(V, New, LGoals, DoNotBind)
),
( DoNotBind == true
->
attributes:unbind_attvar(V)
;
attributes:bind_attvar(V)
),
do_hook_attributes(SWIAtts, New),
lcall(LGoals).
do_hook_attributes([], _).
do_hook_attributes(att(Mod,Att,Atts), Binding) :-
('$undefined'(attr_unify_hook(Att,Binding), Mod)
->
true
;
Mod:attr_unify_hook(Att, Binding)
),
do_hook_attributes(Atts, Binding).
lcall([]).
lcall([Mod:Gls|Goals]) :-
lcall2(Gls,Mod),
lcall(Goals).
lcall2([], _).
lcall2([Goal|Goals], Mod) :-
call(Mod:Goal),
lcall2(Goals, Mod).
prolog:call_residue_vars(Goal,Residue) :-
attributes:all_attvars(Vs0),
call(Goal),
attributes:all_attvars(Vs),
% this should not be actually strictly necessary right now.
% but it makes it a safe bet.
sort(Vs, Vss),
sort(Vs0, Vs0s),
'$ord_remove'(Vss, Vs0s, Residue).
'$ord_remove'([], _, []).
'$ord_remove'([V|Vs], [], [V|Vs]).
'$ord_remove'([V1|Vss], [V2|Vs0s], Residue) :-
( V1 == V2 ->
'$ord_remove'(Vss, Vs0s, Residue)
;
V1 @< V2 ->
Residue = [V1|ResidueF],
'$ord_remove'(Vss, [V2|Vs0s], ResidueF)
;
'$ord_remove'([V1|Vss], Vs0s, Residue)
).
prolog:copy_term(Term, Copy, Goals) :-
term_variables(Term, TVars),
'$get_goalist_from_attvars'(TVars, Goals0),
copy_term_nat([Term|Goals0], [Copy|Goals]).
prolog:call_residue(Goal,Residue) :-
var(Goal), !,
'$do_error'(instantiation_error,call_residue(Goal,Residue)).
prolog:call_residue(Module:Goal,Residue) :-
atom(Module), !,
call_residue(Goal,Module,Residue).
prolog:call_residue(Goal,Residue) :-
'$current_module'(Module),
call_residue(Goal,Module,Residue).
call_residue(Goal,Module,Residue) :-
call(Module:Goal).
project_delayed_goals(G,LGs) :-
(
'$undefined'(modules_with_attributes(_),attributes)
->
attributed(G, NLAV),
NLAV = [_|_]
;
% SICStus compatible step,
% just try to simplify store by projecting constraints
% over query variables.
% called by top_level to find out about delayed goals
attributes:all_attvars(LAV),
LAV = [_|_],
!,
project_attributes(LAV, G),
% now get a list of frozen goals.
attributes:all_attvars(NLAV)
),
!,
get_goalist_from_attvars(NLAV, LGs).
project_delayed_goals(_,[]).
attributed(G, Vs) :-
term_variables(G, LAV),
att_vars(LAV, Vs).
att_vars([], []).
att_vars([V|LGs], [V|AttVars]) :- attvar(V), !,
att_vars(LGs, AttVars).
att_vars([_|LGs], AttVars) :-
att_vars(LGs, AttVars).
% make sure we set the suspended goal list to its previous state!
% make sure we have installed a SICStus like constraint solver.
project_attributes(_, _) :-
'$undefined'(modules_with_attributes(_),attributes), !.
project_attributes(AllVs, G) :-
attributes:modules_with_attributes(LMods),
term_variables(G, InputVs),
pick_att_vars(InputVs, AttIVs),
project_module(LMods, AttIVs, AllVs).
pick_att_vars([],[]).
pick_att_vars([V|L],[V|NL]) :- attvar(V), !,
pick_att_vars(L,NL).
pick_att_vars([_|L],NL) :-
pick_att_vars(L,NL).
project_module([], _, _).
project_module([Mod|LMods], LIV, LAV) :-
'$pred_exists'(project_attributes(LIV, LAV),Mod),
'$notrace'(Mod:project_attributes(LIV, LAV)), !,
attributes:all_attvars(NLAV),
project_module(LMods,LIV,NLAV).
project_module([_|LMods], LIV, LAV) :-
project_module(LMods,LIV,LAV).
% given a list of attributed variables, generate a conjunction of goals.
%
get_conj_from_attvars(TVars, Goals) :-
get_goalist_from_attvars(TVars, [], GoalList, []),
list_to_conjunction(GoalList, Goals).
%
% same, but generate list
%
get_goalist_from_attvars(TVars, GoalList) :-
get_goalist_from_attvars(TVars, GoalList, []).
get_goalist_from_attvars([]) --> [].
get_goalist_from_attvars([V|TVars]) -->
get_goalist_from_attvar(V),
get_goalist_from_attvars(TVars).
get_goalist_from_attvar(V) --> { attvar(V) }, !,
{ attributes:get_all_atts(V, AllAtts) },
all_atts_to_goals(AllAtts, V).
get_goalist_from_attvar(_) --> [].
all_atts_to_goals(AllAtts, _) --> { var(AllAtts) }, !.
all_atts_to_goals(AllAtts, V) -->
{
functor(AllAtts, Mod, _),
arg(1, AllAtts, MoreAtts)
},
attgoals_for_module(Mod, V, AllAtts),
all_atts_to_goals(MoreAtts, V).
%
% check constraints for variable
%
attgoals_for_module(Mod, V, _Gs, GoalListF, GoalList0) :-
% SWI, HProlog
'$pred_exists'(attribute_goals(V,GoalListF,GoalList0), Mod), !,
(
'$notrace'(Mod:attribute_goals(V,GoalListF,GoalList0))
->
true
;
GoalListF = GoalList0
).
attgoals_for_module(Mod, V, _, GoalListF, GoalList0) :-
% SICStus
'$pred_exists'(attribute_goal(V,G),Mod), !,
(
'$notrace'(Mod:attribute_goal(V,G))
->
GoalListF = [G|GoalList0]
;
GoalListF = GoalList0
).
attgoals_for_module(Mod, V, _, GoalList, GoalList).
list_to_conjunction([], true).
list_to_conjunction([G], G) :- !.
list_to_conjunction([G|GoalList], (G,Goals0)) :-
list_to_conjunction(GoalList, Goals0).