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yap-6.3/packages/meld/meldc.yap
Vitor Santos Costa a90e006be0 more meld updates.
2010-11-03 00:33:26 +00:00

224 lines
5.5 KiB
Prolog

:- module(meld_compiler,
[
mcompile/1,
input_graph/1,
run/1
]).
:- use_module(meldi,
[
push/1,
first/2,
min/3,
max/3
]).
:- use_module(library(meld)).
:- use_module(meldtd,
[
meld_top_down_compile/2,
meld_top_down_aggregate/3
]).
:- use_module(library(terms), [
variable_in_term/2
]).
mcompile(Program) :-
open(Program, read, P),
init_mcompile(Program),
repeat,
read_term(P, Term, [variable_names(Vars), module(meld_compiler)]),
(
Term == end_of_file
->
!,
close(P)
;
mcompile(Term, Program, Vars),
fail
).
init_mcompile(Program) :-
retractall(type(_, _, Program, _)).
mcompile(type(T), Program, Vars) :-
ground_term(T, Vars),
type_declaration(T, Program), !.
mcompile((Head :- Body), _, _Vars) :-
rule(Head, Body).
type_declaration(extensional(T), Program) :- !,
functor(T, Na, Arity),
functor(NT, Na, Arity),
assert(meld_topdown:extensional(NT, Na, Arity)),
type_declaration(T, Program).
type_declaration(logical_neighbor(T), Program) :- !,
type_declaration(T, Program).
type_declaration(T, _) :-
functor(T, N, A),
dynamic(meld_program:N/A),
fail.
type_declaration(T, Program) :-
T =.. [P|Args],
check_aggregate(Args, 1, NewArgs, Aggregation, Arg),
!,
NT =.. [P|NewArgs],
meld_top_down_aggregate(T, Aggregation, Arg),
assert_type(NT, Program, aggregation(Aggregation, Arg)).
type_declaration(T, Program) :-
meld_top_down_aggregate(T, horn, _),
assert_type(T, Program, horn).
assert_type(NT, Program, Agg) :-
functor(NT, Na, Ar),
functor(Spec, Na, Ar),
assert(type(Spec, NT, Program, Agg)).
check_aggregate([first(Type)|Args], I, [Type|Args], first, I) :- !.
check_aggregate([max(Type)|Args], I, [Type|Args], max, I) :- !.
check_aggregate([min(Type)|Args], I, [Type|Args], min, I) :- !.
check_aggregate([Type|Args], I, [Type|NewArgs], Agg, Arg) :-
atom(Type),
I1 is I+1,
check_aggregate(Args, I1, NewArgs, Agg, Arg).
ground_term(_, []).
rule(Head, Body) :-
bodytolist(Body, L, []),
compile_goals(L, [], Head),
meld_top_down_compile(Head, Body).
compile_goals([], _, _).
compile_goals([Goal|Goals], Gs, Head) :-
compile_goal(Goal, Goals, Gs, Head),
compile_goals(Goals, [Goal|Gs], Head).
compile_goal((forall G then Do), Goals, Gs, Head) :- !,
% make sure quantified variables are not seen outside
quantified_vars(G,Gs+Goals,NG),
%
% just collect the body into a number of goals
%
collect_body(Gs, [(forall G then Do)|Goals], BLF, BL1),
% make a backup copy for deletion
copy_term(h(Head,BLF,BL1,NG), h(Head,DelBLF,DelBL1,DelNG)),
% add the operation, usually push
extra_head(Head, BL1, []),
% add the delete operation
extra_delete(Head, DelBL1, []),
% create the body as a conjunction
listtobody(BLF, Body),
listtobody(DelBLF, DelBody),
% done
assert(meld_program:(run(NG) :- Body)),
assert(meld_program:(run(delete(DelNG)) :- DelBody)).
compile_goal(Goal, Goals, Gs, Head) :-
collect_body(Gs, Goals, BLF, BL1),
copy_term(h(Head,BLF,BL1,Goal), h(Head,DelBLF,DelBL1,DelGoal)),
extra_head(Head, BL1, []),
extra_delete(Head, DelBL1, []),
listtobody(BLF, Body),
listtobody(DelBLF, DelBody),
assert(meld_program:(run(Goal) :- Body)),
assert(meld_program:(run(deleted(DelGoal)) :- DelBody)).
% quantified variables should not leave the scope of the forall.
quantified_vars(G,Extern,NG) :-
term_variables(G, TVs),
copy_term(G+TVs,NG+NTVs),
bind_external(TVs, NTVs, Extern).
bind_external([], [], _).
bind_external(V.TVs, NV.NTVs, Extern) :-
variable_in_term(Extern, V), !,
V = NV,
bind_external(TVs, NTVs, Extern).
bind_external(_.TVs, _.NTVs, Extern) :-
bind_external(TVs, NTVs, Extern).
% a very simple version
%
collect_body([], []) --> [].
collect_body([G|Gs], MGs) -->
process_goal(G),
collect_body(Gs, MGs).
collect_body([], [G|Gs]) -->
process_goal(G),
collect_body([], Gs).
process_goal((forall Goal then Conj)) --> !,
[(Goal, \+ Conj -> fail ; true)].
process_goal( G ) -->
[G].
extra_head(Head) -->
{ type(Head, _, _, horn) },
[push(Head)].
extra_head(Head) -->
{ type(Head, _, _, aggregation(first, Arg)), freshen(Head, Arg, VHead) },
[ meld_interpreter:first(VHead, Head)].
extra_head(Head) -->
{ type(Head, _, _, aggregation(max, Arg)), freshen(Head, Arg, VHead) },
[ meld_interpreter:max(VHead, Arg, Head)].
extra_head(Head) -->
{ type(Head, _, _, aggregation(min, Arg)), freshen(Head, Arg, VHead) },
[ meld_interpreter:min(VHead, Arg, Head)].
extra_delete(Head) -->
{ type(Head, _, _, horn) },
[meld_interpreter:deleted(Head)].
extra_delete(Head) -->
{ type(Head, _, _, aggregation(first, Arg)), freshen(Head, Arg, VHead) },
[ meld_interpreter:delete_from_first(VHead, Head)].
extra_delete(Head) -->
{ type(Head, _, _, aggregation(max, Arg)), freshen(Head, Arg, VHead) },
[ meld_interpreter:delete_from_max(VHead, Arg, Head)].
extra_delete(Head) -->
{ type(Head, _, _, aggregation(min, Arg)), freshen(Head, Arg, VHead) },
[ meld_interpreter:delete_from_min(VHead, Arg, Head)].
freshen(Head, Arg, VHead) :-
Head =.. [N|Args],
freshen_arg(Arg, Args, VArgs),
VHead =.. [N|VArgs].
freshen_arg(1, [_|Args], [_|Args]) :- !.
freshen_arg(N, A.Args, A.VArgs) :-
N1 is N-1,
freshen_arg(N1, Args, VArgs).
input_graph(Program) :-
open(Program, read, P),
repeat,
read_term(P, Term, [variable_names(_Vars), module(meld_compiler)]),
(
Term == end_of_file
->
!,
close(P)
;
add_graph_fact(Term),
fail
).
add_graph_fact(Term) :-
push(Term).
bodytolist((G1,G2)) -->
!,
bodytolist(G1),
bodytolist(G2).
bodytolist(G) -->
[G].
listtobody([G], G) :- !.
listtobody([G|GL], (G,Gs)) :-
listtobody(GL, Gs).