yap-6.3/library/varnumbers.yap

/**
 * @file   varnumbers.yap
 * @author VITOR SANTOS COSTA <vsc@VITORs-MBP.lan>
 * @date   2006
 *
 * @brief  opposite to numbervars
 *
 *
*/

:- module(varnumbers, [
		  numbervars/1,
		  max_var_number/3,
		  varnumbers/2
              ]).

/**
* @defgroup varnumbers Variabilize term.
* @ingroup library
*
*/


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) :-
	unnumbervars(GT, VT).