code: private void processTag(final StringBuilder builder) {
          boolean started = false;
          while (templateReader.hasNextCharacter()) {
              final char tagCharacter = templateReader.nextCharacter();
              // Stripping whitespaces at the beginning of the tag data:
              if (!started && Strings.isWhitespace(tagCharacter)) {
                  continue;
              }
              started = true;
              if (tagCharacter == syntax.getArgumentOpening()) {
                  // LML parser argument inside a tag. We want to convert these.
                  processArgument();
              } else if (tagCharacter == syntax.getTagOpening() && isNextCharacterCommentOpening()) {
                  // Comment inside a tag. Removing its content.
                  processComment();
              } else if (tagCharacter == syntax.getTagClosing()) {
                  // We're being closed.
                  processTagEntity(builder);
                  return;
              } else {
                  builder.append(tagCharacter);
              }
          }
          throwError("Unclosed tag: " + builder.toString());
      }
docs: Found an open tag that is not a comment. Collecting whole tag data.
  
  @param builder will be used to collect data.