de lang="fsharp"><span onmouseout="hideTip(event, '9', 13)" onmouseover="showTip(event, '9', 13)" class="fn">once</span> <span class="pn">(</span><span class="k">fun</span> <span class="id">_</span> <span class="k">-&gt;</span>
    <span class="pn">(</span><span class="pn">)</span><span class="c">//do this one time at the beginning of the most recently defined context</span>
<span class="pn">)</span>
</code></pre></td>
</tr>
</table>
<h2><a name="before" class="anchor" href="#before">before</a></h2>
<p>Func