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yap-6.3/library/varnumbers.yap
2006-12-27 12:26:33 +00:00

61 lines
1.1 KiB
Prolog

% File : varnumbers.yap
% Author : Vitor Santos Costa
% Updated: 2006
% Purpose: opposite to numbervars
:- module(varnumbers, [
numbervars/1,
max_var_number/3,
varnumbers/2
]).
numbervars(Term) :-
numbervars(Term, 0, _).
max_var_number(V,Max,Max) :- var(V), !.
max_var_number('$VAR'(I),Max0,Max) :- !,
Max is max(I,Max0).
max_var_number(S,Max0,Max) :-
functor(S,_,Ar),
max_var_numberl(0,Ar,S,Max0,Max).
max_var_numberl(I0,Ar,T,Max0,Max) :-
( I0 =:= Ar ->
Max0 = Max
;
I is I0+1,
arg(I,T,A),
max_var_number(A,Max0,MaxI),
max_var_numberl(I,Ar,T,MaxI,Max)
).
varnumbers(GT, VT) :-
max_var_number(GT,0,Max),
Max1 is Max+1,
functor(Vars,vars,Max1),
varnumbers(GT, Vars, VT).
varnumbers(V,_,V) :- var(V), !.
varnumbers('$VAR'(I),Vs,V) :- !,
I1 is I+1,
arg(I1,Vs,V).
varnumbers(S,Vs,NS) :-
functor(S,N,Ar),
functor(NS,N,Ar),
varnumbersl(0,Ar,Vs,S,NS).
varnumbersl(I0,Ar,Vs,S,NS) :-
(I0 =:= Ar ->
true
;
I is I0+1,
arg(I,S,A),
arg(I,NS,NA),
varnumbers(A,Vs,NA),
varnumbersl(I,Ar,Vs,S,NS)
).