Yes, semantically pretty much the same way.

For instance see Re: change perl function in runtime

> and why would there be need to do that,why is that an advantage anyway?

Monkey patching is a way for module users to dynamically adjust foreign modules to their temporary needs w/o changing the installed and officially maintained code.

UPDATE

Ah roboticus did good in mentioning Autoloading. It's a technique for module authors (not module users) who want to decide to compile functions only on demand.

(For instance this can improve compile/load time. IIRC does (did?) CGI.pm something comparable.)