fly defined here:</p>
    <dl>
      <dt>String</dt>
      <dd>
            A sequence of zero or more Unicode characters.
        </dd>
      <dt>Number</dt>
      <dd>
            An integer component optionally prefixed with a minus sign and which may be followed
            by a fraction part and/or an exponent part.</dd>
      <dt>Boolean</dt>
      <dd>
            Literally <code>true</code> or <code>false</code>.</dd>
      <dt>Null</dt>
      <dd>
            Literally <code>null</code>.</dd>
     