ch16.014_prob_ex16.4

Perl Best Practices the source code

##############################################################################
## Example 16.4 (NOT 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  ##
##############################################################################


#  Example 16-4. Adding extra positional arguments to constructors


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


package Client;
use Class::Std::Utils;
{
    my %client_num_of; 
    my %name_of;         # New attribute in base class
 
    sub new {
        # Expect extra positional argument to constructor...
        my ($class, $client_num, $client_name) = @_;
 
        my $new_object = bless anon_scalar(), $class;   
 
        $client_num_of{ident $new_object} = $client_num;
        $name_of{ident $new_object}       = $client_name;
 
        return $new_object;
    }
 
    # etc.
    END { 
        use Data::Dumper 'Dumper';
        warn Dumper [ \%client_num_of, \%name_of ];
    }
}
 
package Client::Corporate;
use base qw( Client );
use Class::Std::Utils;
{
    my %corporation_of;
    my %position_of;        # New attribute in derived class
    sub new {
        # Expect extra positional arguments to constructor...
        my ($class, $client_num, $corp_name, $client_name, $position) = @_;
 
        # Pass extra positional argument to base class constructor...
        my $new_object = $class->SUPER::new($client_num, $client_name);
 
        $corporation_of{ident $new_object} = $corp_name;
        $position_of{ident $new_object}    = $position;
 
        return $new_object;
    }
 
    # etc.
    END { 
        use Data::Dumper 'Dumper';
        warn Dumper [ \%corporation_of, \%position_of ];
    }
}
 
# and later...
 
my $new_client 
    = Client::Corporate->new( '124C1', 'Florin', 'Humperdinck',  'CEO' );