I always like input magic, but there are caveats: What if the user decides to access your sub as a real function? That is, xpkg::mproc()... and worse, if the user additionally throws an hashref at the beginning? Your code wouldn't recognize it...

Check the following: is it a ref? If not, is it a string with your package as a name? -&bt; you are called as a class. Skip the first argument. If not, keep the first. If it is a ref, is the ref equal to the name of your package? Than the first argument is $self. If not, you need to keep the first argument. You see, four possible cases here.

Just a nitbit: no memory allocation is needed in perl.