Perl 5 doesn't implement function overloading in the sense that I think you are talking about. If you wish to achieve the same effect it is up to you to make your function examine the parameter list and then do what you want. Usually this is just a matter of supplying default values to missing arguments. But if you want you can look at the parameters then redispatch the request to other functions.

If your dispatching logic will be complicated then you may wish to take advantage of the fact that method dispatch on objects lets you easily dispatch on the type of your first argument.