ue even in case of failure (unless ctxt == NULL).</p>
<div class="variablelist"><table border="0"><col align="left" /><tbody><tr><td><span class="term"><i><tt>ctxt</tt></i>:</span></td><td>the expression context</td></tr><tr><td><span class="term"><i><tt>left</tt></i>:</span></td><td>left expression</td></tr><tr><td><span class="term"><i><tt>right</tt></i>:</span></td><td>right expression</td></tr><tr><td><span class="term"><i><tt>Returns</tt></i>:</span></td><td>the node or NULL in case of error</td></tr><