untainting easier and more readable.
All functions return an untainted value if the test passes, and undef if it
fails. This means that you should always check for a defined status
explicitly. Don't assume the return will be true. (e.g. is_username('0'))
The value to test is always the first (and often only) argument.
WWW: http://search.cpan.org/dist/Data-Validate-IP/
PR: ports/119264
Submitted by: Tuc <freebsd-ports at t-b-o-h.net>