w which character set a <code class="computeroutput"><span class="keyword">char</span></code>
          or <code class="computeroutput"><span class="keyword">wchar_t</span></code> is operating on.
          For example, the <code class="computeroutput"><span class="identifier">alnum</span></code>
          parser works differently with ISO8859.1 and ASCII encodings. Where necessary,
          Spirit encodes (tags) the parser with the character set.
        </p>
<p>
          We have a namespace for each cha