anchor.diff:  
   String _normalizeReference(String s) => _trimAndReplaceSpaces(s).toUpperCase();
   
  -// TODO make constructors in ParseResult (new ParseResult.success)
  -
   class _LinkReference extends Block {
     String reference;
     String normalizedReference;
  
positive.code:                   buildBuffer();
                  }
  
                  // TODO Speedup by checking impossible starts
                  ParseResult<String> lineRes = anyLine.run(s, position);
                  assert(lineRes.isSuccess);
                  List<Block> lineBlock = block
  
negative.code:               buildBuffer();
                List<Block> lineBlock =
                    lazyLineBlock.parse(line + "\n", tabStop: tabStop);
                if (!closeParagraph &&
                    lineBlock.length == 1 &&
                    lineBlock[0] is Para) {
  