#!/usr/bin/perl --
use strict; use warnings;
use Tk;
use Tk::WidgetDump;
use Tk::ObjScanner;
my %ons;
my $mw = tkinit();
for (1 .. 3) {
    my $goner = $_;
    $ons{$_} = $mw->Button(
        -text => "B $_",
        -command => sub {
            delete($ons{$goner})->destroy; ## this works, proper closure
#~             delete($ons{$_})->destroy; ## this doesnt, $_ is alias
        }
    )->pack;
}
$mw->WidgetDump; ## before scan_object
Tk::ObjScanner::scan_object( { mw => $mw, ons => \%ons } ); ## after WidgetDump
MainLoop();