public function set_merge_var($key, $value = null, $rcpt = null)
	{
		is_array($key) or $key = array($key => $value);

		if (is_null($rcpt))
		{
			$this->merge_vars = \Arr::merge($this->merge_vars, $key);
		}
		else
		{
			$merge_vars = \Arr::get($this->rcpt_merge_vars, $rcpt, array());
			$this->rcpt_merge_vars[$rcpt] = \Arr::merge($merge_vars, $key);
		}

		return $this;
	}