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";