Note that Attribute::Params::Validate ships with Params::Validate.
So far, I've never needed to use the handlers form; Params::Validate has been perfectly adequate for my needs.
However, I've found that not everybody likes Params::Validate, and I've had cases of people choosing not to use my CPAN modules owing to dependency on P::V. This inspired me to come up with Module::Optional including Params::Validate::Dummy, which allows people to still use code with calls to validate(), validate_pos() etc. without installing P::V.
Not all of my CPAN modules that use Params::Validate have been changed to use Module::Optionsl yet, but this is something I intend to incorporate on their next release.
Oh Lord, won’t you burn me a Knoppix CD ?
My friends all rate Windows, I must disagree.
Your powers of persuasion will set them all free,
So oh Lord, won’t you burn me a Knoppix CD ?
(Missquoting Janis Joplin)