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prologswi-prolog

Prolog functor , swi-prolog

Check if the predicate functor(Term, F, A) succeeds if Term has functor F and arity A by defining a functor

The code I've tried is

likes(Mary,pizza)

Is this correct?

Solution

  • As described at https://www.swi-prolog.org/pldoc/man?predicate=functor/3

    ?- functor(likes('Mary', pizza), Name, Arity).
Name = likes,
Arity = 2.

?- functor(Term, likes, 2).
Term = likes(_,_).

    Beware: Variables start with a capital letter, so the value Mary is 'Mary', because Mary is instead a reference to a variable.