If you want clean function overloading in Perl take a look at Class::Multimethods.

There's also the appropriately named overload module, which I have yet to use but looks interesting.

Update: Here's an example with Class::Multimethods:

use Class::Multimethods;

multimethod add => ('#', '#')
                => sub { $ans = $_[0] + $_[1]; print $ans, "\n"  };

multimethod add => ('$', '$')
                => sub { $ans = $_[0] . $_[1]; print $ans, "\n" };

add(1, 2);
add("Foo", "Bar");
[download]

Is this what you're thinking of?