This module defines meta-predicates that apply a predicate on all members of a list.
call(Goal, Xi) 
succeeds.
call(Goal, Xi) 
fails.call(Pred, X) succeeds and
Excluded contains the remaining elements.call(Pred, Xi, Place), 
where Place must be unified to one of <, = 
or >.
Pred must be deterministic.
foldl(P, [X11,...,X1n], ..., [Xm1,...,Xmn], V0, Vn) :-
      P(X11, ..., Xm1, V0, V1),
      ...
      P(X1n, ..., Xmn, V', Vn).
scanl(P, [X11,...,X1n], ..., [Xm1,...,Xmn], V0,
      [V0,V1,...,Vn]) :-
      P(X11, ..., Xm1, V0, V1),
      ...
      P(X1n, ..., Xmn, V', Vn).