while
          parsing using a skipper. A simple example is the common task of matching
          a C keyword. Consider:
        </p>
<pre class="programlisting"><span class="string">"description"</span> <span class="special">&gt;&gt;</span> <span class="special">-</span><span class="identifier">lit</span><span class="special">(</span><span class="string">":"</span><span class="special">)</span> <span class="special">&gt;&gt;</span> <span class="special">*(</span><span class="identifier">char_</span> <span