 member(?Elem, 
?List)True if Elem is a member of List. The SWI-Prolog 
definition differs from the classical one. Our definition avoids 
unpacking each list element twice and provides determinism on the last 
element. E.g. this is deterministic:
member(?Elem, 
?List)True if Elem is a member of List. The SWI-Prolog 
definition differs from the classical one. Our definition avoids 
unpacking each list element twice and provides determinism on the last 
element. E.g. this is deterministic:
    member(X, [One]).
- author
- Gertjan van Noord