de>
          (see the description of error handlers - <span class="bold"><strong>FIXME</strong></span>:
          insert link), then you need to instantiate the error handler using <code class="computeroutput"><span class="identifier">retry</span></code> or <code class="computeroutput"><span class="identifier">fail</span></code>,
          for instance:
</p>
<pre class="programlisting"><span class="identifier">rule</span> <span class="identifier">r</span><span class="special">&lt;</span><span class="identi