function preg_replace_safe($search, $replace, $subject, $evaluator = NULL) {
	if (is_null($evaluator)) {
		$evaluator = function($code) { return eval($code); };
	}
	
	if (is_array($subject)) {
		return array_map(function($subject) use ($search, $replace) {
			return preg_replace_safe($search, $replace, $subject);
		}, $subject);
	} else {
		if (is_array($search) && is_array($replace)) {
			$replacements = array_map(function($a, $b) { return [$a, $b]; }, $search, $replace);
		} else if(is_array($search)) {
			$replacements = array_map(function($a) use($replace) { return [$a, $replace]; }, $search);
		} else {
			$replacements = [[$search, $replace]];
		}
		
		foreach ($replacements as $replacement) {
			list ($s, $r) = $replacement;
			if (is_callable($r)) {
				$subject = preg_replace_callback($s, $r, $subject);
			} else {
				$stripped = preg_replace("/^(.)(.*\\1[a-z]*)e([a-z]*)$/si", "$1$2$3", $s);
				if ($stripped != $s) {
					$subject = preg_replace_callback($stripped, function($matches) use ($r, $evaluator) {
						$code = preg_replace_callback("/\\$(?|\{(\\d+)\}|(\\d+))/", function($m) use ($matches) {
							return addslashes($matches[(int) $m[1]]);
						}, $r);
						return $evaluator("return " . $code . ";");
					}, $subject);
				} else {
					$subject = preg_replace($s, $r, $subject);
				}
			}
		}
		
		return $subject;
	}
}