MEMBER-IF
=========

syntax: (member-if <predicate> <list>)

This function and the function MEMBER work similar,
but MEMBER-IF searches for the first element with
the right predicate. <predicate> is a function
with an argument. MEMBER-IF returns the remaining
list or NIL.

example:       >(member-if #'numberp '(a b c 1 2 3))
               (1 2 3)