        <li>
          <b>CH_IS_UPPER</b> is TRUE if CH is an upper case letter.
        </li>
        <li>
          <b>CH_LOW</b> lowercases a single character.
        </li>
        <li>
          <b>CH_ROMAN_TO_I4</b> returns the integer value of a single Roman digit.
        </li>
        <li>
          <b>CH_SCRABBLE</b> returns the character on a given Scrabble tile.
        </li>
        <li>
          <b>CH_SWAP</b> swaps two characters.
        </li>
        <li>
          <b>CH_TO_DIGIT</b> retur