my @button = defined $idx ? (
    OK     => sub { &edit_entry($idx,$legentry); $tl->destroy; },
    Apply  => [\&edit_entry, $idx, $legentry],
    Delete => sub { &delete_entry($idx); $tl->destroy; },
    Cancel => [$tl => 'destroy'],
)
: (
    OK     => sub { &add_entry($legentry); $tl->destroy; },
    Apply  => [\&add_entry, $legentry],
    Cancel => [$tl => 'destroy'],
);

for($tl->Frame) {
    $_->pack;
    while(my ($text, $command) = splice @button, 0, 2) {
        $_->Button(-text => $text, -command => $command)
          ->pack(-side => 'left');
    }
}