validate NRIC golang

nric_validator.go

var 	RegexNRIC             = regexp.MustCompile(`^(S|T|F|G)\d{7}[A-Z]$`)

func ValidateNRIC(s string) bool {
	nric := strings.ToUpper(s)
	if !RegexNRIC.Match([]byte(nric)) {
		return false
	}

	weight := 0
	n, _ := strconv.Atoi(string(nric[1]))
	weight += n * 2

	n, _ = strconv.Atoi(string(nric[2]))
	weight += n * 7

	n, _ = strconv.Atoi(string(nric[3]))
	weight += n * 6

	n, _ = strconv.Atoi(string(nric[4]))
	weight += n * 5

	n, _ = strconv.Atoi(string(nric[5]))
	weight += n * 4

	n, _ = strconv.Atoi(string(nric[6]))
	weight += n * 3

	n, _ = strconv.Atoi(string(nric[7]))
	weight += n * 2

	if nric[0] == 'T' || nric[0] == 'G' {
		weight += 4
	}

	rorate := weight % 11
	if nric[0] == 'S' || nric[0] == 'T' {
		return nric[8] == st[rorate]
	}
	if nric[0] == 'F' || nric[0] == 'G' {
		return nric[8] == fg[rorate]
	}
	return false
}