You can use a templating system. If your needs are simple, Text::BasicTemplate should get the job done.

On a side point, in a recent application I wasn't allowed to use a templating system (for various political reasons), and used much the same subroutine-based solution you seem to be talking about. I'd usually have the sub return the string instead of printing it out, but I could see having it print out directly if the program is small.