in reply to A warning about overloading assignment methods

I think if i understand this properly you can see the same thing at work without overload. Try this: 

package T;
use Data::Dump::Streamer;

sub foo { \$_[0] }
sub bar { my $x=shift; \$x }

my $o=bless [],'T';

Dump($o->foo,$o->bar,$o)->Names(qw(foo bar o))->Out();
__END__
$foo = \$o;
$bar = \do { my $v = 'V: $o' };
$o = bless( [], 'T' );
$$bar = $o;

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What happening here is that you seeing the difference between copy semantics (what happens with assignment) and aliasing semantics (what happens when you take a reference to an alias).

But i know you well enough to know this isnt a surprise to you, so Im wondering if you could explain in more detail perhaps with a minimal case we can run to see the effect you mean.

---
demerphq

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Re^2: A warning about overloading assignment methods
by diotalevi (Canon) on Apr 20, 2005 at 08:43 UTC

    Here's my short test code which demonstrates the data structure prior to returning and how it instamagically turned into a self-ref afterward.

    Here's the data before returning and after returning it from the -= method.

    $expected = bless( \bless( \1, 'T' ), 'T' );
$got = bless( \$got, 'T' );

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    And here's the sample code.

    package T;
use Data::Dump::Streamer;
sub D {
    my ( $name, $val ) = @_;
    Dump()
      ->Purity( 0 )
        ->Names( $name )
          ->Data( $val )
            ->Out();
    return;
}

use overload(
    '-=' => sub {
        my $new = bless \ $_[0], "T";
        D( new => $new );
        return $new;
    },

    '""' => sub {
        my $self = shift;
        D( self => $self );
        return $$self
    }
);

sub new {
    my ( $class, $val ) = @_;
    bless \ $val, $class;
}

package main;
$o = T->new( 1 );
$o -= 2;
"$o";

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