right
sub parse_datestring {
    # parses a datestring
    # - allows to provide a format of how to interprete day,month,year in the datestring.
    #      default format is: DD/MM/YY
    #       ->  calling this method with  format=>'d.m.y'  computes faster than format=>'dd.mm.yy' !
    # - any non-digit character in the datestring is considered a delimiter!
    # - 2-digit years will be considered 1930-2029
    # - by default the date calculated from the datestring will be validated
    #       -> validate=>'0'  disables validation
    # - return value is an array of ($day, $month, $year)
    #       -> $day and $month are returned 2-digit
    #       -> $year is returned 4 digit
    #       ===> in case of invalid date ALL of the above will be undef
    #       ===> in case of omitted day or month, the appropriate array elements will be undef
    # - in case of errors such as invalid date $errstr is set and might be retrieved by $handle->errstr();
    # - example call:
    #    my ($day,$mon,$year) = $handle->parse_datestring( 'datestring' => '02.02.02',
    #                                                      'format' => 'd.m.y',   # optional
    #                                                      'validate' => 0,       # optional
    #                                                     )
    #
    my $self = shift;
    my %classargs = (@_);
    # reset $errstr
    $errstr = '';
    my ($d,$m,$y);
    # make sure 'datestring' is not ommited!
    if (! $classargs{'datestring'}) {
        $errstr = 'ERROR parsing datestring: \'datestring\' is missing';
    }
    # make sure delimiter becomes '/'
    $classargs{'datestring'} =~ s/\D+/\//gi;
    # handle input like '06.2004' or '6.06' - assuming month of year
    if ($classargs{'datestring'} =~ /^(\d{1,2})\/(\d{2,4})$/gi ) {
        $m = $1;
        $y = $2;
    }
    # handle input like '2004' - assuming year
    elsif ($classargs{'datestring'} =~ /^\d{2,4}$/gi ) {
        $y = $classargs{'datestring'};
    }
    # handle all other input - requesting days (possibly regardless of the year like '06.08'
    # need to reorder according to format and delimiter
    else {
        if (! $classargs{'format'}) {  # assume default format DD/MM/YY(YY)
            ($d, $m, $y) = split(/\//, $classargs{'datestring'});
        }
        else {            # parse with provided formatting information
            my (%lookup,$first,$second,$third);  #%position);
            # make sure delimiter becomes '/'
            $classargs{'format'} =~ s/[^dmyDMY]+/\//gi;right
            # need lower case
            $classargs{'format'} = lc ($classargs{'format'});
            if (length($classargs{'format'}) >5) {
                $classargs{'format'} =~ s/([dmyDMY])+/$1/g;
            }
            ($first,$second,$third) = split(/\//, $classargs{'format'});
            ($lookup{$first}, $lookup{$second}, $lookup{$third})
                                 = split(/\//, $classargs{'datestring'});
            $d = $lookup{'d'};
            $m = $lookup{'m'};
            $y = $lookup{'y'};
        }
    }
    if (length($d) == 1) { $d = '0'.$d; }
    if (length($m) == 1) { $m = '0'.$m; }
    if (length($y) == 2) {
        if ($y >= 30) { $y += 1900; }
        else { $y += 2000; }
    }

    # validate date
    # NOTE: validate only if $m or $d are available!
    unless ($classargs{'validate'} eq '0') {
        my $m_index = int($m)-1;
        # validate month
        if ($m) {
            if (($m_index <0) || ($m_index >11)) {
                $errstr = "ERROR parsing datestring: not a valid month";
            }
        }
        if ($d) {
            # validate day
            my @days_per_month = (31,28,31,30,31,30,31,31,30,31,30,31);
            # check for leap-year
            if ( ((($y % 4) == 0) && (($y % 100) != 0))
                || (($y % 400) == 0)
                ) {
               $days_per_month[1] ++;
            }
            # check day
            my $d_integer = int($d);
            if ( ($d_integer < 1) || ($d_integer > $days_per_month[$m_index]) ) {
                $errstr = "ERROR parsing datestring: not a valid day in month $m";
            }
        }
    }
    return ($d, $m, $y);
}