Directives: reject

complex_rule:      {print "In complex rule...\n";} <reject>

complex_rule:       simple_rule '+' 'i' '*' simple_rule
                  | 'i' '*' simple_rule
                  | simple_rule

• A <reject> directive fails, causing the current production to fail immediately.
• Can be useful for side-effects.
• <reject: expression> only rejects if the condition is true.