preg_replace out CSS comments?

Here's a solution:

$regex = array(
"`^([\t\s]+)`ism"=>'',
"`^\/\*(.+?)\*\/`ism"=>"",
"`([\n\A;]+)\/\*(.+?)\*\/`ism"=>"$1",
"`([\n\A;\s]+)//(.+?)[\n\r]`ism"=>"$1\n",
"`(^[\r\n]*|[\r\n]+)[\s\t]*[\r\n]+`ism"=>"\n"
);
$buffer = preg_replace(array_keys($regex),$regex,$buffer);

Taken from the Script/Stylesheet Pre-Processor in Samstyle PHP Framework

See: http://code.google.com/p/samstyle-php-framework/source/browse/trunk/sp.php

csstest.php:

<?php

$buffer = file_get_contents('test.css');

$regex = array(
"`^([\t\s]+)`ism"=>'',
"`^\/\*(.+?)\*\/`ism"=>"",
"`([\n\A;]+)\/\*(.+?)\*\/`ism"=>"$1",
"`([\n\A;\s]+)//(.+?)[\n\r]`ism"=>"$1\n",
"`(^[\r\n]*|[\r\n]+)[\s\t]*[\r\n]+`ism"=>"\n"
);
$buffer = preg_replace(array_keys($regex),$regex,$buffer);
echo $buffer;

?>

test.css:

/* testing to remove this */
.test{}

Output of csstest.php:

.test{}

I don't believe you can use grouping within a negated character class like you have there. What you're going to want to use is called Assertions, of which there are two types. "look-ahead" and "look-behind".

The pattern you're looking for in English is basically, "forward slash, literal wildcard, anything that isn't followed by a forward slash or anything other than a literal wildcard that is followed by a forward slash or a forward slash that isn't preceded by a literal wildcard zero or more times, literal wild card, forward slash"

<?php

$str = '/* one */ onemore
/*
* a
* b
**/
stuff // single line
/**/';

preg_match_all('#/\*(?:.(?!/)|[^\*](?=/)|(?<!\*)/)*\*/#s', $str, $matches);
print_r($matches);

?>

I had the same issue. To solve it, I first simplified the code by replacing "/ASTERIX" and "ASTERIX/" with different identifiers and then used those as the start and end markers.

$code = str_replace("/*","_COMSTART",$code);
$code = str_replace("*/","COMEND_",$code);
$code = preg_replace("/_COMSTART.*?COMEND_/s","",$code);

The /s flag tells the search to go onto new lines