use strict;
use warnings;

sub outer {
   my ($x) = @_;

   sub inner { # XXX bad
      print("$x\n");
   }

   inner();
}

outer(4);
outer(5);
inner();

##</code><code>##

Variable "$x" will not stay shared at a.pl line 8.
4
4    # XXX Want 5.
4    # XXX Don't want inner sub to be public

##</code><code>##

use strict;
use warnings;

sub outer {
   my ($x) = @_;

   local *inner = sub {
      print("$x\n");
   };

   inner();
}

outer(4);
outer(5);
inner();

##</code><code>##

4
5
Undefined subroutine &main::inner called at a.pl line 16.