function ExpandRanges(ranges : String) : array of Integer;
begin
   for var range in ranges.Split(',') do begin
      var separator = range.IndexOf('-', 2);
      if separator > 0 then begin
         for var i := range.Left(separator-1).ToInteger to range.Copy(separator+1).ToInteger do
            Result.Add(i);
      end else begin
         Result.Add(range.ToInteger)
      end;
   end;
end;

var expanded := ExpandRanges('-6,-3--1,3-5,7-11,14,15,17-20');
PrintLn(JSON.Stringify(expanded));