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   1  # $Id: Boolean.pm,v 1.7 2000/07/03 08:54:47 matt Exp $
   2  
   3  package XML::XPath::Boolean;
   4  use XML::XPath::Number;
   5  use XML::XPath::Literal;
   6  use strict;
   7  
   8  use overload
   9          '""' => \&value,
  10          '<=>' => \&cmp;
  11  
  12  sub True {
  13      my $class = shift;
  14      my $val = 1;
  15      bless \$val, $class;
  16  }
  17  
  18  sub False {
  19      my $class = shift;
  20      my $val = 0;
  21      bless \$val, $class;
  22  }
  23  
  24  sub value {
  25      my $self = shift;
  26      $$self;
  27  }
  28  
  29  sub cmp {
  30      my $self = shift;
  31      my ($other, $swap) = @_;
  32      if ($swap) {
  33          return $other <=> $$self;
  34      }
  35      return $$self <=> $other;
  36  }
  37  
  38  sub to_number { XML::XPath::Number->new($_[0]->value); }
  39  sub to_boolean { $_[0]; }
  40  sub to_literal { XML::XPath::Literal->new($_[0]->value ? "true" : "false"); }
  41  
  42  sub string_value { return $_[0]->to_literal->value; }
  43  
  44  1;
  45  __END__
  46  
  47  =head1 NAME
  48  
  49  XML::XPath::Boolean - Boolean true/false values
  50  
  51  =head1 DESCRIPTION
  52  
  53  XML::XPath::Boolean objects implement simple boolean true/false objects.
  54  
  55  =head1 API
  56  
  57  =head2 XML::XPath::Boolean->True
  58  
  59  Creates a new Boolean object with a true value.
  60  
  61  =head2 XML::XPath::Boolean->False
  62  
  63  Creates a new Boolean object with a false value.
  64  
  65  =head2 value()
  66  
  67  Returns true or false.
  68  
  69  =head2 to_literal()
  70  
  71  Returns the string "true" or "false".
  72  
  73  =cut