I don't know how things work in Switzerland (where you seem to live according to your home node), but in the European Union you can't patent software. So, by releasing your perl module you shouldn't risk anything, at least until you decide to move to a less developer-friendly place.

Copyright is another issue, but to break that you should have to actually copy other people's code without the necessary permissions.

Disclaimers: following the suggestions in this post without professional legal assistance might lead to arrest, detention and unwanted intimacy with inmates.

Antonio