Fun with Matching Braces
PHP, -4 (156 - 20*3 - 30 - 50 - 20)
&lt;?php $x=preg_replace(&quot;!(//.*|/\*.*\*/|[^()[\]{}&lt;&gt;])!sm&quot;,'',$argv[1]);while(strlen($x)!=strlen($x=str_replace(str_split('()[]{}&lt;&gt;',2),'',$x)));print $x?0:1;


It removes comments
It filters out all characters different than (, ), [, ], {, }, &lt;, &gt;
It replaces all (), [], {}, &lt;&gt; pairs until there are no matches
Prints 1 if the string is empty, 0 otherwise

(Edit: changed the regex; the source code is now 156 instead of 175)