protected function affix($affix, $value, $propagate = true)
	{
		$affixes = ['prefix', 'suffix'];

		if (in_array($affix, $affixes)) {

			if (is_scalar($value)) {
				$this->{$affix} = strval($value);
				return $this->propagateMutation($affix, $propagate);
			}

			throw new InvalidArgumentException("The given {$affix} cannot be converted to a string.");

		}
	}