Package test1;

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

Ignored Tokens
  blank;

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

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

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