public function type($mapping_type) {
		$args = func_get_args();
		$mapping_type = array_shift($args);
	
		//check if mapping arguments are defined
		if (empty($args))
			return $this->merge(['map.type' => $mapping_type]);
	
		return $this->merge(['map.type' => $mapping_type, 'map.params' => $args]);
	}