This module provides various type-testing functions. These are
intended for functions that, unlike most Perl code, care what type of
data they are operating on. For example, some functions wish to behave
differently depending on the type of their arguments (like overloaded
functions in C++).

These functions only provide type classification; they do not enforce
type restrictions. Type enforcement may, of course, be built using
these classification functions, but the reader's attention is drawn
to Params::Validate.

WWW:	http://search.cpan.org/dist/Params-Classify/