Hmmm ... strange. That doesn't seem to work. I tried the additional parameter, I even tried to add a ref to the tied variable to the object later and it did not work. The variable appeared not to be tied within FETCH and stayed tied outside:

---------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;
[download]

and it prints

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

That is I do have a reference to the right scalar, yet it's not tied ?!?

I use Perl 5.8 (ActivePerl build 805) under Win2000serverSP4.

I also tried the same code using Perl 5.6.1 (ActivePerl build 631, same OS) and there it also did not report the reference to be tied, but did succeed to untie it:

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

Strange.

Jenda
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
   -- Rick Osborne

Edit by castaway: Closed small tag in signature