IDENTIFIER-OF
=============

syntax: (identifier-of <evaluates-to kb-object>)

Warning: yet not implemented!

This function returns the identifier of a knowledge 
base object.

example: >(ask [city _a-city]
            (kb-format "~%~A" (identifier-of _a-city)))
         PARIS
         LONDON
         NEW-YORK
         BERLIN
         NIL