RATIONALP
=========

syntax: (rationalp <object>)   ;Common Lisp command
        (ratiop <object>)      ;Babylon Lisp command

        ==> T | NIL

This function verifies, whether the object is a ratio.
A function is true (T), when its argument is a ratio,
otherwise it is false (NIL).

examples:      >(rationalp 3/2)
               T

               >(rationalp "a")
               NIL