rd">const</span> s1<span class="special">;</span></pre></div>
<div class="refsect1">
<a name="idp207240512"></a><h2>Description</h2>
<p>To create a sub-match, assign a sub-expression to the sub-match placeholder. For instance, (s1= _) will match any one character and remember which character was matched in the 1st sub-match. Later in the pattern, you can refer back to the sub-match. For instance, (s1= _) &gt;&gt; s1 will match any character, and then match the same character again.</p>
<p>After a successful