# Wochentag numerisch {num}, 
# abgekürzt{abb}, voll{full}
sub wd{
    my $self = shift;
    my $day   = shift;
    my $month = shift;
    my $year  = shift;
    return {split /\s+/, strftime( 
        'num %w abb %a full %A', 0, 0, 0, 
        $day, $month-1, $year-1900 
    )};
}