Yes. And it offers me a way to expand my previous answer. You say that a template is "a format used for describing output". I'll go further, saying that a template generates a language (i.e. a set of strings). On the other hand a regular expression denotes a language, then is usable to recognize strings that belong or not to a set. Since the original question asked for a way to recognize strings in a set, I suggested to change terminology in order to be conducted to the right abstraction that Perl provides.