Not the same thing. DSLs are not the same as extending the functionality of the interpreter. And it's basically the flexibility of perl as a procedural/functional/declarative/OO language (i.e. lack of assumptions of how you want to work) with its roots in practical natural linguistics (as opposed to theoretical as with lisp) that makes this possible. Yes, that does mean coding with some discipline (Perl::Critic and Moose & friends helps here), and some things are more of a pain in the arse than with a more opinionated language, but it seems a reasonable trade off to me.