t to <tt>[^[:digit:]]</tt>)</li>
<li><tt>s</tt> - Space character (equivalent to <tt>[[:space:]]</tt>)</li>
<li><tt>S</tt> - Non-space character (equivalent to <tt>[^[:space:]]</tt>)</li>
<li><tt>w</tt> - Word character (equivalent to <tt>[[:alnum:]_]</tt>)</li>
<li><tt>W</tt> - Non-word character (equivalent to <tt>[^[:alnum:]_]</tt>)</li>
</ul>


<h3>Literals</h3>
<a name="literal"></a>

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<tr><td>
<pre>
<i>literal</i> ::= <i>ordinary-character</i>
        |   <b>"