ch14.017_prob_ex14.1

Perl Best Practices the source code

#!/usr/bin/perl -s

##############################################################################
## Example 14.1 (NOT RECOMMENDED) from Chapter 14 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 14-1. Command-line parsing via perl -s


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

# Use the -s shebang line option to handle command-lines of the form:
#
#     > orchestrate -in=source.txt -out=dest.orc -v
 
# The -s automatically parses the command line into these package variables...
use vars qw( $in $out $verbose $len);
 
# Handle meta-options (which will appear in package variables whose names
# start with a dash. Oh, the humanity!!!)...
no strict qw( refs );
X::Version->throw() if ${-version};
X::Usage->throw()   if ${-usage};
X::Help->throw()    if ${-help};
X::Man->throw()     if ${-man};
 
# Report intended behaviour...
if ($verbose) {
    print "Loading first $len chunks of file: $in\n"
}
# etc.


package UNIVERSAL;
use Carp;

sub throw {
    my ($class) = @_;

    croak "Show $class here\n";
}