You don't change it - it's already infinite (well, up to the size of available virtual memory.) Of course, there's a warning you usually get when the recursion gets 100 deep, but that can be turned off with no warnings;

And you say that perl is stackless in the 'stackless python' sense, so am I to assume that Perl's stack is not tied to the 'C' stack?

Correct. There are a few things in Perl that can blow the C stack (such as certain pathological regexes), but mostly you're only limited by available memory.

Dave M