PO::import_from_file( string $filename )

	function import_from_file($filename) {
		$f = fopen($filename, 'r');
		if (!$f) return false;
		$lineno = 0;
		while (true) {
			$res = $this->read_entry($f, $lineno);
			if (!$res) break;
			if ($res['entry']->singular == '') {
				$this->set_headers($this->make_headers($res['entry']->translations[0]));
			} else {
				$this->add_entry($res['entry']);
			}
		}
		PO::read_line($f, 'clear');
		if ( false === $res ) {
			return false;
		}
		if ( ! $this->headers && ! $this->entries ) {
			return false;
		}
		return true;
	}