}

    var match = commitRE.exec(t);
    if (match) {
        return "https://golang.org/change/" + match[1];
    }

    if (pkgRE.test(t)) {
        // TODO: make this smarter, using a list of packages + substring matches.
        // Get the list from godoc itself in JSON format?
        return "https://golang.org/pkg/" + t;
    }

    return null;

	// TODO(rsc): more work on 32-bit platforms
	C.mpz_set_si(&z.i[0], C.long(x))
	return z
}

// SetString interprets s as a number in the given base
// and sets z to that value.  The base must be in the range [2,36].
// SetString returns an error if s cannot be parsed or the base is invalid.
func (z *Int) SetString(s string, base int) error {
	z.doinit()
	if base < 2 || base > 36 {
		return os.ErrInvalid
	}