ch16.057_best

Perl Best Practices the source code

##############################################################################
##   Code fragment (Recommended) from Chapter 16 of "Perl Best Practices"   ##
##     Copyright (c) O'Reilly & Associates, 2005. All Rights Reserved.      ##
##  See: http://www.oreilly.com/pub/a/oreilly/ask_tim/2001/codepolicy.html  ##
##############################################################################


# Standard modules...
use strict;
use warnings;
use IO::Prompt;
use Carp;
use English qw( -no_match_vars );
use Data::Alias;
use Readonly;


package Phonebook;
use Class::Std;
{
    my %entries_of : ATTR;
 
    # Any method call is someone's name: store their phone number or get it...
    sub AUTOMETHOD {
        my ($self, $ident, $number) = @_;
 
        my $subname = $_;   # Requested subroutine name is passed via $_
 
        # Return failure if not a get_<name> or set_<name>
        # (Next AUTOMETHOD() in hierarchy will then be tried instead)...
        my ($mode, $name) = $subname =~ m/\A ([gs]et)_(.*) \z/xms
            or return;
 
        # If get_<name>, return a handler that just returns the old number...
        return sub { return $entries_of{$ident}->{$name}; }
            if $mode eq 'get';
 
        # Otherwise, set_<name>, so return a handler that updates the entry
        # and then returns the old number...
        return sub {
            $entries_of{$ident}->{$name} = $number;
            return;
        };
    }
}
 
# and later...
 
my $lbb = Phonebook->new();
 
$lbb->set_Jenny(867_5309);
$lbb->set_Glenn(736_5000);
 
print $lbb->get_Jenny(), "\n";
print $lbb->get_Glenn(), "\n";

$lbb->call_Jenny();