parseTupleContent static method

List<String> parseTupleContent(String input)

Implementation

static List<String> parseTupleContent(String input) {
  if (input.isEmpty) {
    return <String>[];
  }

  if (input.startsWith(',') || input.endsWith(',')) {
    throw ArgumentError(
      'parsing error: tuple content should not start with comma',
    );
  }

  if (input.contains(',,')) {
    throw ArgumentError(
      'parsing error: tuple content should not have consecutive commas',
    );
  }

  final parentStack = ListQueue<int>();
  final parentSegments = <Segment>[];

  for (var i = 0; i < input.length; i++) {
    final char = input[i];
    if (char == '(') {
      parentStack.add(i);
    } else if (char == ')') {
      if (parentStack.isEmpty) {
        throw ArgumentError(
            'parsing error: tuple parentheses are not balanced: $input');
      }

      final leftParentIndex = parentStack.removeLast();
      if (parentStack.isEmpty) {
        parentSegments.add(Segment(leftParentIndex, i));
      }
    }
  }

  if (parentStack.isNotEmpty) {
    throw ArgumentError(
        'parsing error: tuple parentheses are not balanced: $input');
  }

  var strCopied = input;
  for (var i = parentSegments.length - 1; i >= 0; i--) {
    strCopied = strCopied.substring(0, parentSegments[i].L) +
        strCopied.substring(parentSegments[i].R + 1);
  }

  final tupleSeg = strCopied.split(',');
  var parenSegCount = 0;
  for (var i = 0; i < tupleSeg.length; i++) {
    if (tupleSeg[i].isEmpty) {
      tupleSeg[i] = input.substring(parentSegments[parenSegCount].L,
          parentSegments[parenSegCount].R + 1);
      parenSegCount++;
    }
  }

  return tupleSeg.toList();
}