package TableMap::Undef;
use strict;

use overload
  "0+" => sub { return undef },
  "bool" = sub { return undef };

sub new{
  my $a={};
  my $x=shift;
  bltess ($a,ref($x)||$x);
  tie(%$a,"TableMap::Undef::TIE");
  return $a;
};

sub AUTOLOAD { return new TableMap::Undef; };

sub DESTROY {};

package TableMap::Undef::TIE;
use strict;

sub TIEHASH {
  my $a={};
  my $x=shift;
  bless ($a,ref($x)||$x);
  return $x;
};

sub FETCH { return new TableMap::Undef; };