You could use global variables (trully global with use vars) but I would use a closure... that's what they're for. By the way it doesn't look like you are using stict. bad idea.

use strict; # ALWAYS!
$a = LetterPrinter( "a" );
$b = LetterPrinter( "b" );

$a->(); # these can also be called with ampersand
$b->(); # ie:  &$b;

sub LetterPrinter
{
  my $letter = shift;
  return sub{ print $letter, $/ };
}
[download]