解读golang中的const常量和iota

const (
    MaxInt = int(^uint(0) >> 1)
    MinInt = -MaxInt - 1
)
const PI = 3.14
PI = 3.14159//编译错误，Cannot assign to PI

const (
    a   = 1                  //1 (iota=0)
    b                        //1 (iota=1，同上一行，相当于写b=1)
    c   = b + iota           //3 (iota=2，b=1)
    d                        //4 (iota=3，同上一行，相当于写b+iota，b=1)
    e                        //5 (iota=4，同上一行，相当于写b+iota，b=1)
    f   = "last one but one" //  (iota=5)
    end = iota               //6 (iota=6)
)
fmt.Println(a, reflect.TypeOf(a))
fmt.Println(b, reflect.TypeOf(b))
fmt.Println(c, reflect.TypeOf(c))
fmt.Println(d, reflect.TypeOf(d))
fmt.Println(e, reflect.TypeOf(e))
fmt.Println(f, reflect.TypeOf(f))
fmt.Println(end, reflect.TypeOf(end))
/* 
输出：
1 int
1 int
3 int
4 int
5 int
last one but one string
6 int
*/

const SUCCESS = true
const FAIL = false

const (
CONST1 = 0
CONST2 = 1
CONST3 = 2
)

type UserStatus int

const (
USER_STATUS_NORMAL UserStatus = iota
USER_STATUS_DISABLED_LOGIN
USER_STATUS_DELETE
)

package user
//Status 用户类型.
type Status int
const (
//STATUS_NORMAL 状态正常
STATUS_NORMAL Status = iota
//STATUS_DISABLED_LOGIN 禁止登录.
STATUS_DISABLED_LOGIN
//STATUS_DELETE 已删除.
STATUS_DELETE
)