This module grovels in perl's guts to see if a variable really is a number, as opposed to a string that just looks like a number, and whether it is an integer or not. ie, it can tell the difference between "100", 100, and 100.0. 100 is an integer. "100" is a string that looks like an integer. 100.0 is numerically equivalent to 100, but it is only accurate to 4 significant figures. To install, do the usual: perl Makefile.PL make make test make install You may use, modify and distribute this code under the same terms as you may use, modify and distribute perl itself.