File Coverage

blib/lib/Object/Generic/False.pm

Criterion	Covered	Total	%
statement	17	20	85.0
branch			n/a
condition	1	2	50.0
subroutine	9	11	81.8
pod	0	3	0.0
total	27	36	75.0

#
# Object::Generic::False.pm
#
# A perl object that evaluates to a boolean false value
# but which still allows method calls.
#
#   use Object::Generic::False qw( false );
#   my $n = false;      # returns global $Object::Generic::False::_false_
#   print "n is false" if not $n;
#   print "n->foo->bar is also false" if not $n->foo->bar;
#
# See the bottom of this file for the documentation.
#
# $Id: False.pm 378 2005-06-07 19:00:32Z mahoney $
#
package Object::Generic::False;
use strict;
use warnings;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(false);
our $_false_ = new Object::Generic::False;     # The global returned by false().
use overload
  q("")   => sub {return ''},         # Also autogenerates numeric false as 0.
  q(<=>)  => sub {return 0 <=> $_[1]},
  q(cmp)  => sub {return '' cmp $_[1]},
  # --- arithmetic ---
  q(+)    => \&false,
  q(-)    => \&false,
  q(neg)  => \&false,
  q(*)    => \&false,
  q(/)    => \&false,
  q(%)    => \&false,
  q(**)   => \&false,
  # --- strings -------
  #q(.)   => \&false,
  q(x)    => \&false,
  # --- bits ----------
  q(&)    => \&false,
  q(|)    => \&false,
  q(~)    => \&false,   # Should this perhaps return a (true) Object::Generic?
  ;
sub new {
  my $class = shift;
  my $false = shift || 0;
  return bless \$false => $class;
}
sub DESTROY {   # Defined here so that AUTOLOAD won't handle it.
}
sub AUTOLOAD {
  return shift;
}
sub false {
  return $_false_;
}
sub error {
  my $self = shift;
  return $$self;
}

1;

__END__