By dispatch on prototype I mean that when Perl looks up a function it can figure out what function to call based on the name and the look of the arguments.

As for whether it is doable, probably. It would be hairy. It would not fit well in the list-oriented nature of Perl. People often find the APIs they create with such facilities to be very confusing. And Perl does not support it because it does not support having 2 functions in the same package of the same name at the same time.

Anyways about prototypes, I completely side with Tom Christiansen on this. Unless you have a darned good reason you need them, they are a bad idea in Perl...