It's impossible to figure out which arguments to a function are required in perl. It's also impossible to even figure out all the subroutines, due to autoload and other types of dynamic subroutine declaration.

That said, there have been many threads here about documentation generators. They generally require you to format your comments in a specific manner, and then they parse your code and spit out pretty HTML documents. In general, these solutions are okay, but most people prefer to use pod (plain old documentation).

pod is nice because there are a zillion scripts out there to do stuff with it, and all the CPAN modules use it, so there's no need to learn multiple documentation syntaxes.