r. We moved the <code class="computeroutput"><span class="special">*</span></code> to the front for the same reasons we did
          in <span class="emphasis"><em>Spirit.Qi</em></span>: we must work with the syntax rules of
          C++. But if you know regular expressions (and for sure you remember those
          C++ syntax rules) it will start to look very familiar in a matter of a
          very short time.
        </p>
<p>
          Any expression that evaluates to a generator may be used with the Kl