><dd><p>Matches preceding pattern zero or once only</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">|</span></code></dt><dd><p>Matches a pattern on either side of the <code class="docutils literal notranslate"><span class="pre">|</span></code></p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">()</span></code></dt><dd><p>Saves a matched subexpression, which can be referenced
in the <code class="docutils literal notranslate"><span class="pre">REGEX</span> <s