---------testUntie.pl---------
#!perl
use Data::Lazy;

print "ref=" . \$x . "\n";

tie $x, 'Data::Lazy', sub {sleep 1; 2};
tied($x)->{'var'} = \$x;

print "Tied: " . tied($x) . "\n";
print "\$x=$x\n";
print "Tied: " . tied($x) . "\n";
print "\$x=$x\n";

---------Data/Lazy.pm---------
package Data::Lazy;
#...
sub TIESCALAR {
  my $pack = shift;
  my $self = {};
  $self->{code} = shift;
  $self->{'store'} = $_[0] if $_[0];
  $self->{'type'} = 0;
#  $self->{'var'} = $_[1] if $_[1];
  bless $self => $pack;		# That's it?  Yup!
}
#...
sub FETCH {
  my $self = shift;
  if ($self->{'type'} == 0) { # scalar
   return $self->{value} if exists $self->{value};
   if (ref $self->{code} eq 'CODE') {
         $self->{value} = &{$self->{code}};
   } else {
         $self->{value} = eval $self->{code};
   }
   if ($self->{'store'} == LAZY_STOREVALUE and exists $self->{'var'}) {
	   my $var = $self->{'var'};
print "Try to untie $var tied to " . tied($$var) . "\n";
	   untie($$var);
	   $$var = $self->{value};
	   undef $self;
	   return $$var;
   } else {
	   $self->{value};
   }
  } # ... elsif array and hash
}
#...
1;

##</code><code>##

ref=SCALAR(0x1a4587c)
Tied: Data::Lazy=HASH(0x15d55d0)
Try to untie SCALAR(0x1a4587c) tied to
$x=2
Tied: Data::Lazy=HASH(0x15d55d0)
$x=2

##</code><code>##

ref=SCALAR(0x1ab2cc0)
Tied: Data::Lazy=HASH(0x1abf078)
Try to untie SCALAR(0x1ab2cc0) tied to
$x=2
Tied:
$x=2