如何限制Golang中变量的值？

Question

guys!

I know golang idiomatic don't have setter and getter. But I need to restrict value of variables in Golang.

I defined new type

type MyNewStringType string

And variables, that was defined as MyStringType, need to restrict value.

Variables of MyStringType can have only 3 values: "Yes", "No", "I don't know"

How can I do it in Golang? In Java, C++ I have setter and getter, but in Golang is not normal.

I know, I can create

type MyNewStringType struct {
   Variable string
}

and create

func(m *MyNewStringType) SetVariable(newVar string) error {
  if newVar == "Yes" || newVar == "No" || newVar == "I don't know" {
    m.Variable = newVar
    return nil
  } else {
    return errors.New("Wrong value")
  }

But I think it's wrong way.

Answer 1

Short awnser:

type MyString string
const (
    YES MyString = "yes"
    NO = "no"
    DONTKNOW = "i dont know"
)

func foo(arg MyString){
    fmt.Print(arg)
}

foo(YES) //success, prints "yes"

foo("jop") //fails to compile