At this point, the variable is no longer valid and could have been overwritten by some other value.

This isn't true.

Resulting errors are many times this line:

And neither is this. You can't get that error from the code you posted.

The code is actually correct. Yes, $int goes out of scope on the last line of the snippet. But that only limits its visibility, not its lifespan. By capturing the lexical, the anon sub extends its life.

Even if the code is called in a loop, everything will work. A new $int will be created. This is easy to demonstrate: 

my @subs;
for (qw( 123 456 789 )) {
   my $int = $_;
   push @subs, sub { $int };
}

say $_->() for @subs;

[download]
123
456
789

[download]

In contrast, note how the following code only has one $int that's captured three times: 

my $int;
my @subs;
for (qw( 123 456 789 )) {
   $int = $_;
   push @subs, sub { $int };
}

say $_->() for @subs;

[download]
789
789
789

[download]

Maybe you didn't use a properly-scoped lexical variable?

I could have used for my $int in the first snippet, but I wanted to make the two snippets easier to contrast.

In reply to Re: Interpolate variable into regexp at time of definition rather than execution, as a filter for Path::Iterator::Rule by ikegami
in thread Interpolate variable into regexp at time of definition rather than execution, as a filter for Path::Iterator::Rule by ecm

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