f a range, enclose it in <tt>[.</tt> and <tt>.]</tt>.
</p>


<h3>Assertions</h3>
<a name="assertion"></a>

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<tr><td>
<pre>
<i>assertion</i> ::= <b>"^"</b>
          |   <b>"$"</b>
          |   <b>"\"</b> <i>assertion-character</i>
</pre>
</td></tr>
</table>

<p>
The expressions <tt>^</tt> and <tt>$</tt> are called "left anchor" and
"right anchor", respectively.  The left anchor matches the empty
string at the beginning of the string.  The right anchor matches the
e