/span></code></pre>
<p> The default action policy forwards to:</p>
<pre>
    <code><span class=identifier>actor</span><span class=special>(</span><span class=identifier>first</span><span class=special>, </span><span class=identifier>last</span><span class=special>);</span></code></pre>
<p> If the attribute <tt>val</tt> is of type nil_t. Otherwise:</p>
<pre>
    <code><span class=identifier>actor</span><span class=special>(</span><span class=identifier>val</span><span class=special>);</span></code></pre>
<a 