e>
<p>
A branch is one or more <i>pieces</i> concatenated.  It matches a
match for the first piece, followed by a match for the second piece,
and so on.
</p>


<table bgcolor="#e0e0f0" cellpadding="10">
<tr><td>
<pre>
<i>piece</i> ::= <i>atom</i>
      |   <i>atom</i> <a href="#repeat-operator"><i>repeat-operator</i></a>
      |   <i>atom</i> <a href="#approx-settings"><i>approx-settings</i></a>
</pre>
</td></tr>
</table>
<p>
A piece is an <i>atom</i> possibly followed by a repeat operator or an
expression 