#!/usr/bin/perl

use strict;
use warnings;

package Cute;

sub TIEHASH {bless {}, shift}
sub STORE   {my ($self, $key, $sub) = @_; 
             $$self{$key} = sub {$sub->($key)}}
sub FETCH   {${$_[0]}{$_[1]}}

package main;

tie my %hash, 'Cute';

my $greeting = sub {print "Hello, $_[0]\n"};

$hash{world} = $greeting;
$hash{earth} = $greeting;

foreach my $key (qw /world earth/) {
    &{$hash{$key}};
}
 
__END__
Hello, world
Hello, earth