c:\@Work\Perl>perl -wMstrict -le
"{ package ProcessData;
   ;;
   use warnings;
   use strict;
   use Carp qw(croak);
   ;;
   sub new {
     my ($pkg) = $_[0];
     bless {
       _dispatch_table => {},
       }, $pkg;
     }
   ;;
   sub add_subroutine {
     if($_[1] && $_[2]) {
       if(ref($_[2]) eq \"CODE\") {
         ${$_[0]->{_dispatch_table}}{$_[1]} = $_[2];
         }
       else {
         croak qq{non-CODE reference '$_[2]' passed to add_subroutine()};
         }
       }
     else {
       croak \"Insufficient arguments passed to add_subroutine(). \";
       }
   }
   ;;
   sub process_data {
     my $self = shift;
     ;;
     die qq{no dispatch given} unless @_;
     my $dispatch = shift;
     die qq{unknown dispatch '$dispatch'}
       unless exists $self->{_dispatch_table}{$dispatch};
     ;;
     return $self->{_dispatch_table}{$dispatch}->(@_);
   }
   ;;
   sub process_locations {
     my $self = shift;
     return $self->process_data('locations', @_);
     }
   ;;
   }
 ;;
 use warnings;
 use strict;
 ;;
 my $pd = ProcessData->new();
 ;;
 $pd->add_subroutine('locations', \&get_locations);
 ;;
 $pd->process_locations(qw(here there everywhere));
 ;;
 sub get_locations { print qq{we got stuff: @_} }
"
we got stuff: here there everywhere