semantics are perl5. version is 0.001_019. start symbol is S.
S: A, Y. 'rule0'. # Call me the start rule
note: you can also call me Rule 0.
A: . 'rule1'. # Call me Rule 1
A: B, C. 'rule2'. # Call me Rule 2
B: . q{rule3}. # Call me Rule 3
C: . q{rule4}. # Call me Rule 4
C: Y. q{rule5}. # Call me Rule 5
Y: /Z/. 'rule6'. # Call me Rule 6