Matching

start:        die  /^\Z/

die:          'd' number
            | number 'd' number

number:       /\d+/

• A rule matches if one of its productions matches; the parser will try alternative productions in order.
• A production matches if each of its items matches in the order given.
• Items match:
  • Subrule: if the rule matches.
  • Token: literal or regex match.
  • Action: if the code returns a defined value.
  • Directive: we'll come back to that.
  • Comment: always a match; no text is consumed.
• Tokens match a prefix of the to be parsed strings. The part that is matched will be consumed; this is similar to matching with regular expressions.