in reply to Re: Recursive substitution
in thread Recursive substitution
Thanks very much. I realised shortly after posting that I hadn't explained why I didn't want the most natural answer (current explanation: because I don't, that's why), but didn't update my post in time.
By the way, I think that s/$pat/$sub/ is (effectively) a no-op unless m/$pat/, so I think that it's redundant to do a separate m/$pat/ check.