code: func POSTagShortcut(l Lexeme) (POSTag, bool) {
  	switch l.LexemeType {
  	case Number:
  		return NUM, true
  	case Punctuation:
  		return PUNCT, true
  	case Symbol:
  		return SYM, true
  	case URI:
  		return X, true
  	case Date:
  		return NUM, true
  	case Time:
  		return NUM, true
  	case EOF:
  		return X, true
  	}
  	return X, false
  }
docs: // POSTagShortcut is a shortcut function to help the POSTagger shortcircuit some decisions about what the tag is