ExpandRanges := proc( s :: string )
  uses  StringTools;
  local DoOne := proc( input )
    uses StringTools;
    local lo, hi, pos;
    if IsDigit( input ) or input[ 1 ] = "-"
     and IsDigit( input[ 2 .. -1 ] ) then
      parse( input )
    else
      pos := Search( "--", input );
      if pos > 0 then
        lo := input[ 1 .. pos - 1 ];
        hi := input[ 1 + pos .. -1 ];
      elif input[ 1 ] = "-" then
        pos := FirstFromLeft( "-", input[ 2 .. -1 ] );
        if pos = 0 then
          lo := input;
          hi := lo
        else
          lo := input[ 1 .. pos ];
          hi := input[ 2 + pos .. -1 ];
        end if;
      else
        pos := FirstFromLeft( "-", input );
        if pos = 0 then
          error "incorrect syntax"
        end if;
        lo := input[ 1 .. pos - 1 ];
        hi := input[ 1 + pos .. -1 ];
      end if;
      lo := parse( lo );
      hi := parse( hi );
      seq( lo .. hi )
    end if
  end proc:
  map( DoOne, map( Trim, Split( s, "," ) ) )
end proc: