As ikegami said, subs are global:

#!perl
use v5.10;
use strict;
use warnings;

my $a = shift;

sub f {
  say "global f";
}

sub g {
  say "global g";
  my ($a) = @_;
  sub f {
    say "local f ($a)"; # line 16
  }
  f();
}

f();
g(shift);
f();

__END__

C:\Temp>localsub.pl
Variable "$a" will not stay shared at C:\Temp\localsub.pl line 16.
Subroutine f redefined at C:\Temp\localsub.pl line 15.
Use of uninitialized value $a in concatenation (.) or string at C:\Tem
+p\localsub.pl line 16.
local f ()
global g
Use of uninitialized value $a in concatenation (.) or string at C:\Tem
+p\localsub.pl line 16.
local f ()
Use of uninitialized value $a in concatenation (.) or string at C:\Tem
+p\localsub.pl line 16.
local f ()

C:\Temp>localsub.pl AAA BBB
Variable "$a" will not stay shared at C:\Temp\localsub.pl line 16.
Subroutine f redefined at C:\Temp\localsub.pl line 15.
Use of uninitialized value $a in concatenation (.) or string at C:\Tem
+p\localsub.pl line 16.
local f ()
global g
local f (BBB)
local f (BBB)

[download]

What is a strange behavior is that variables got stuck with a value, even if it is assigned after it's first use... That does not seem to be a compile time assignment.

Conclusion: always define global subroutines or pass variables as parameters to them if defined locally for clarity.

In reply to Re: closure clarity, please by vitoco
in thread closure clarity, please by 7stud

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