Thanks Merlyn, "scarier" is just what I needed:)

In your example, wouldn't $my_sub_level need to have been declared previously in order to have something to localise?

From perlsub A local just gives temporary values to global (meaning package) variables. It does not create a local variable.

I was presuming a global variable was already available. If you have use strict, you'd have to "use vars" the variable, yes.

Or, just make it a package variable explictly:

sub my_subroutine {
  local $main::my_subroutine_level = $main::my_subroutine_level + 1;
  ....
}
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-- Randal L. Schwartz, Perl hacker

But local also works with lexical variables, doesn't it? IMHO, I didn't think it was necessary for $my_sub_level to be a global, per se. Since perl 5.6 it's been possible to localize nearly any variable; I've localized member variables of class instances, lexicals, arbitrary scalars within complex multi-level structures (hash containing arrayrefs of hashrefs containing hashrefs, etc.).

Granted, localizing such a thing may (temporarily, subject to the enclosing scope) hide the thing being localized with what is effectively a global, but that's an internal implementation detail that seems to have mattered not, at least with the code in which I've used it.

To return to the original question, isn't $depth referred to as a closure? Or (perhaps my semantics are incorrect) is sub recurse the closure? Semantics aside, I'm surprised no one mentioned the word.

dmm

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