📜  prolog 检查谓词是否存在 - 无论代码示例

📅  最后修改于: 2022-03-11 15:00:53.510000             🧑  作者: Mango

代码示例1
?- current_predicate(a/1).
false.

?- functor(A,a,1),predicate_property(A,visible).
false.

?- functor(A,a,1),current_predicate(_,A).
false.

?- assert(a(42)).
true.

?- current_predicate(a/1).
true.

?- functor(A,a,1),predicate_property(A,visible).
A = a(_G136).

?- functor(A,a,1),current_predicate(_,A).
A = a(_G122).