Actually, I'm talking more about validating the arguments passed to a given subroutine, which may or may not be in the context of a Web application. Interestingly enough, though, I'm actually rather familiar with D::FV, as we use it for validating data for our Web applications. I had never thought about using that to validate the arguments to a given sub. It seems like cutting balsa wood with a power saw, but it certainly would be an option and it would be pretty easy to build the profiles on the fly.