Negative value format with in parentheses
<p>normally php will output negative integer with this format <code>-1234</code>, how to it show in parentheses format <code>(1234)</code></p>

<p>example:  </p>

<pre><code>$foo = 10 - 20;
// output: $foo = -10
// expected output $foo = (10)
</code></pre>
