#!/usr/bin/perl

# http://perlmonks.org/?node_id=1203952

use strict;
use warnings;

# Callback functions ---------------------------------------

sub first::callback {
   my $z = pop;
   print "in first_callback, z=$z\n";
   return 1;
}

sub last::callback {
   my $z = pop;
   print "in last_callback, z=$z\n";
   return 2;
}

sub UNIVERSAL::callback { -1 }

# Implementation of dispatch table -------------------------
# (You need to write this code)

#my %op_table = ( first  => \&first_callback,
#                 last   => \&last_callback,
#               );

sub invoker
{
   my ($name, $z) = @_;
   $name->callback($z);
}

# Main program for testing ---------------------------------

for my $name ( "first", "last", "fred" ) {
   my $rc = invoker( $name, $name . '-arg' );
   print "$name: rc=$rc\n";
}