Validar palabra palíndroma en Go

func isPalindrome(s string) bool {
	clean := toAlpha(s)
	left := 0
	right := len(clean) - 1

	for left <= right {
		if clean[left] != clean[right] {
			return false;
		}
		left++
		right--
	}

	return true
}

func toAlpha(s string) string {
	r := regexp.MustCompile("[^a-zA-Z0-9]")
	return strings.ToLower(r.ReplaceAllString(s, ""))
}