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

Since local works with variables in the symbol table and lexical (my) variables have no symbol table entries, you can't use local on a my variable. For example, this fails:

perl -e 'my $foo; local $foo'
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with the error:

Can't localize lexical variable $foo at -e line 1.
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-- Mike

--
just,my${.02}

Hmmm, I seem to recall localizing a hash value within a deeply nested structure, like:

my $root = { some_object => obj };
$root->{some_object} = new Object;
my $arrayref = $root->{some_object}->objectMethodReturningEmbeddedArra
+yref();
$arrayref->[0] = 5;
{
  local $arrayref->[0] = 0;
  # execute some code, which sees 0 not 5
}

# now array element is 5 again
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I specifically remember wanting to do something like that in 5.004 and not being able to, having instead to do something like this:

# ...
$arrayref->[0] = 5;
# ...
{
  my $lcl = $arrayref->[0];
  $arrayref->[0] = 0;

  # execute some code, which sees 0 not 5

  $arrayref->[0] = $lcl;
}

# now array element is 5 again
[download]

dmm