convert current working directory to perl package name

[metaperl]

hello,

I would like to create a simple interactive Emacs Lisp function.

When invoked, this command will obtain the current directory as a full
pathname:

/home/metaperl/prg/DBIx-Cookbook/lib/DBIx/Cookbook/Recipe/Searching

It will then get rid of everything from the start of line to (and
including) lib:

DBIx/Cookbook/Recipe/Searching

Then it will replace each forward slash with "::"

DBIx::Cookbook::Recipe::Searching

The resulting string will be put into the buffer at point.

I've written a macro to do this, but dont know how to save a macro as
a command to my .emacs.el file