Re: Where is the maplist built-in predicate ?

On 2010/06/09, at 18:00, [email protected] wrote:

> maplist/2 is a built-in predicate in SWI Prolog.

Wrong, is a library predicate:

$ swipl
...
For help, use ?- help(Topic). or ?- apropos(Word).

?- predicate_property(maplist(_,_), P).
P = interpreted ;
P = imported_from(apply) ;
P = transparent ;
P = (meta_predicate maplist(1, ?)) ;
P = file('/opt/local/lib/swipl-5.11.1/library/apply.pl') ;
P = line_count(157) ;
P = number_of_clauses(1) ;
false.

> I try this :
> 
> %maplist(?P, ?L) : Apply the predicate P on each element in L
> maplist(P, []).
> maplist(P, [X|Xn]) :- call(P, X),maplist(P, Xn).
> 
> But I get this :
> | ?- maplist(odd, [z]).
> no

Shouldn't the query be:

| ?- maplist(odd, [s(z)]).

Cheers,

Paulo


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