sub compactRanges {

    #
    # @pieces contains the list of numbers
    # %parts will contain a compact form, such that $start..$end
    #   is represented as $parts{$start} = $end
    # $seperator contains the character(s) placed between the
    #   values
    # %wrap_negatives contains a flag indicated if negative
    #   values should be wrapped in some way, and the leading
    #   and trailing values if so
    #
    my (@pieces) = @_;
    my $seperator      = '..';
    my %wrap_negatives =
      ( 'flag' => 1, 'leading' => '[', 'trailing' => ']' );
    my (%parts);

    @pieces = sort { $a <=> $b } @pieces;

    {
        my ($i);
        my ($recent);
        $recent = $parts{$i} = $i = shift (@pieces);
        while (@pieces) {
            $i = shift (@pieces);
            $recent = $i if ( $i - 1 > $parts{$recent} );
            $parts{$recent} = $i;
        }
    }

    foreach my $k ( sort { $a <=> $b } keys(%parts) ) {
        my $str =
          (     ( $wrap_negatives{'flag'} )
            and ( $k < 0 ) ? $wrap_negatives{'leading'} : '' )
          . $k
          . (   ( $wrap_negatives{'flag'} )
            and ( $k < 0 ) ? $wrap_negatives{'trailing'} : '' );
        $str .= $seperator
          . (
                ( $wrap_negatives{'flag'} )
            and ( $parts{$k} < 0 ) ? $wrap_negatives{'leading'}
            : ''
          )
          . $parts{$k}
          . (
                ( $wrap_negatives{'flag'} )
            and ( $parts{$k} < 0 ) ? $wrap_negatives{'trailing'}
            : ''
          )
          if ( $parts{$k} != $k );
        push ( @pieces, $str );
    }
    return (@pieces);
}