variable method

Implementation

Parser variable() => seq2(
  ref0(identifier),
  [
    seq3(
      ref1(token, '['),
      ref0(expression).plusSeparated(ref1(token, ',')),
      ref1(token, ']'),
    ),
    seq2(ref1(token, '.'), ref0(identifier)),
    ref1(token, '^'),
  ].toChoiceParser().star(),
);