Package test2;

Tokens
  number = [ '0' .. '9' ]+;
  plus   = '+';
  minus  = '-';
  mult   = '*';
  div    = '/';
  l_par  = '(';
  r_par  = ')';
  blank  = ( ' ' | 13 | 10 )+;

Ignored Tokens
  blank;

Productions
  expr = 
    {term}  term |
    {plus}  expr plus  term |
    {minus} expr minus term;

  term  = 
    {factor} factor |
    {mult}   term mult factor |
    {div}    term div  factor;

  factor = 
    {number} number | 
    {expr}   l_par expr r_par;