tifier">i</span><span class="special">&gt;</span> <span class="identifier">args</span><span class="special">,</span>
	<span class="identifier">Context</span><span class="special">&amp;</span> <span class="identifier">context</span><span class="special">)</span>
</pre>
<p>
          <code class="computeroutput"><span class="identifier">first</span></code> points to the position
          in the input sequence before the rule is matched. <code class="computeroutput"><span class="identifier">last</span></code>