#!/usr/bin/perl

use Set::IntSpan qw(grep_set); # grep_set will be used shortly

%subscribers = ( );

# Create and populate the sets.
$subscribers{ 'Oak Grove' }  = Set::IntSpan->new( "1-33,35-68" );
$subscribers{ 'Elm Street' } = Set::IntSpan->new( "1-12,43-87" );

print $subscribers{ 'Elm Street' }->run_list, "\n";

$just_north_of_railway = 32;
$oak_grovers_south_of_railway =
   grep_set { $_ > $just_north_of_railway } $subscribers{ 'Oak Grove' };

print $oak_grovers_south_of_railway->run_list, "\n";

foreach (15..41) { $subscribers{ 'Elm Street' }->insert( $_ ) }