public static function parameterize($string, $sep = '-'){
		# replace accented chars with their ascii equivalents
		$parameterized_string = static::transliterate($string);
		# Turn unwanted chars into the separator
		$parameterized_string = preg_replace('/[^a-z0-9\-_]+/i', $sep, $parameterized_string);
		if(!(is_null($sep) || empty($sep))){
			$re_sep = preg_quote($sep); # CoreExt\Regexp::escape
			# No more than one of the separator in a row.
			$parameterized_string = preg_replace("/{$re_sep}{2,}/", $sep, $parameterized_string);
			# Remove leading/trailing separator.
			$parameterized_string = preg_replace("/^{$re_sep}|{$re_sep}$/i", '', $parameterized_string);
		}
		return strtolower($parameterized_string);
	}