Re: Where is the maplist built-in predicate ?

On 2010/06/09, at 17:17, [email protected] wrote:

> Hello,
> 
> I am using GNU Prolog 1.3.1.
> 
> I use this code :
> 
> % int(?I) : I is an integer
> int(z).
> int(s(X)) :- int(X).
> 
> % odd(?I) : I is an odd integer
> odd(s(z)).
> odd(s(s(X))) :- odd(X).
> 
> % intzodd(?I) : I is an odd integer or zero (z)
> intzodd(X) :- X=z.
> intzodd(X) :- odd(X).
> 
> % listzodd(?L) : L is a list which each element is an odd integer or zero (z)
> listzodd(X) :- maplist(intzodd, X).
> 
> And I don't find the maplist built-in predicate.
> 
> | ?- listzodd([z]).
> uncaught exception: error(existence_error(procedure,maplist/2),listzodd/1)
> 
> Where is the maplist built-in predicate, please?

maplist/2 is not a built-in predicate in GNU Prolog and, as far as I know, in any other Prolog compiler. Some Prolog compilers, however, provide it in a library. You will need to define it yourself. Is easy.

Cheers,

Paulo


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