CARDINALITY-OF-SET
==================

syntax: (cardinality-of-set <evaluates-to 
                            <set-of X (...)>>)

This function determines the cardinality of the set.
It returns the number of elements. 


Warning: length works the same on vectors
         and lists !!! 

example: >(list-to-set '(1 2 3) :TYPE 'integer)
         #<set-of INTEGER (...)>

         >(cardinality-of-set *)
         3