parseOn method

@override Result<Sequence4<R1, R2, R3, R4>> parseOn(Context context)

Primitive method doing the actual parsing.

The method is overridden in concrete subclasses to implement the parser specific logic. The methods takes a parse context and returns the resulting context, which is either a Success or Failure context.

Implementation

@override
Result<Sequence4<R1, R2, R3, R4>> parseOn(Context context) {
  final result1 = parser1.parseOn(context);
  if (result1.isFailure) return result1.failure(result1.message);
  final result2 = parser2.parseOn(result1);
  if (result2.isFailure) return result2.failure(result2.message);
  final result3 = parser3.parseOn(result2);
  if (result3.isFailure) return result3.failure(result3.message);
  final result4 = parser4.parseOn(result3);
  if (result4.isFailure) return result4.failure(result4.message);
  return result4.success(Sequence4<R1, R2, R3, R4>(
      result1.value, result2.value, result3.value, result4.value));
}