ch15.068_prob

Perl Best Practices the source code

##############################################################################
## Code fragment (NOT RECOMMENDED) from Chapter 15 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;

my $curr_state = 'Bitstring';
Readonly my $VERBOSITY_BIT => 27;

$curr_state->set_bit($_, !$curr_state->get_bit($_)) for $VERBOSITY_BIT;
 
print 'The current state is: ', 
      do {
          my @bits;
          while (defined(my $bit = $curr_state->get_bit(scalar @bits))) {
              push @bits, $bit;
          }
          @bits;
       }, 
       "\n";


package Bitstring;

sub get_bit {
    my ($self, $n) = @_;
    return if $n > 12;
    return int rand 2;
}

sub set_bit {
    my ($self, $n, $new_val) = @_;
    print "Setting bit $n to $new_val\n";
    return;
}