ch13.060_best

Perl Best Practices the source code

##############################################################################
##   Code fragment (Recommended) from Chapter 13 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;


# Define the X::EOF class, inheriting useful behaviours 
# from Exception::Class::Base...
use Exception::Class (
    'X::EOF' => {
        # Specify that X::EOF objects have a 'handle' attribute 
        # and a corresponding handle() method...
        fields => [ 'handle' ],
    },
);
 
# Redefine the message to which an X::EOF object stringifies...
sub X::EOF::full_message {
    my ($self) = @_;
    return 'Filehandle ' . $self->handle . ' at EOF';
}


use Carp;
eval { croak( X::EOF->new(handle => 'none') ) }
    or warn $OS_ERROR;
X::EOF->throw( handle => 'some' );