nsitive.
<li>n - Forces special handling of the new line character. See the REG_NEWLINE flag in 
the <a href="tre-api.html">API Manual</a>.
<li>r - Causes the regex to be matched in a right associative manner rather than the normal
left associative manner.
<li>U - Forces repetition operators to be non-greedy unless a <tt>?</tt> is appended.
</ul>
<h2>BRE Syntax</h2>

<p>
The obsolete basic regexp (BRE) syntax differs from the ERE syntax as
follows:
</p>

<ul>
<li><tt>|</tt> is an ordinary character, and the