parseTensorIndicesGroup static method

List<(bool, LatexNode)> parseTensorIndicesGroup(LatexParserContext ctx, LatexTokenStream stream)

Parses a tensor indices list from a braced token stream.

Implementation

static List<(bool, LatexNode)> parseTensorIndicesGroup(
  LatexParserContext ctx,
  LatexTokenStream stream,
) {
  if (stream.peek() is! LeftBraceToken) {
    return [];
  }
  stream.advance(); // consume '{'

  final indices = <(bool, LatexNode)>[];

  while (!stream.isEOF() && stream.peek() is! RightBraceToken) {
    final token = stream.peek();
    if (token is SuperscriptToken) {
      stream.advance();
      final content = ctx.parseFactor();
      if (content != null) {
        indices.add((true, content));
      }
    } else if (token is SubscriptToken) {
      stream.advance();
      final content = ctx.parseFactor();
      if (content != null) {
        indices.add((false, content));
      }
    } else if (token is WhitespaceToken) {
      stream.advance();
    } else {
      stream.advance();
    }
  }

  if (!stream.isEOF()) {
    stream.advance(); // consume '}'
  }

  return indices;
}