public function setExtension($extension) {
		$pathinfo = pathinfo($this->pathname);
		
		$pathname = new Text($pathinfo['dirname']);
		if (!empty($pathinfo['dirname'])) {
			$pathname = $pathname->append('/');
		}
		
		$this->init($pathname
			->append($pathinfo['filename'])
			->append('.')
			->append($extension))
		;

		return $this;
	}