Immutable Struct in Golang

问题

Is it possible to define an immutable struct in Golang? Once initialized then only read operation on struct's field, no modification of field values. If so, how to do that.

回答1:

It is possible to make a struct to be read-only outside of package by making it's members non-exported and providing readers. For example:

package mypackage

type myReadOnly struct {
  value int
}

func (s myReadOnly) Value() int {
  return s.value
}

func NewMyReadonly(value int) myReadOnly{
  return myReadOnly{value: value}
}

And usage:

myReadonly := mypackage.NewMyReaonly(3)
fmt.Println(myReadonly.Value())  // Prints 3

回答2:

There is no way to mark fields/variables as read only in a generic way. The only thing you could do is marking fields/variable as unexported (first letter small) and provide public getters to prevent other packages editing variables.

来源：https://stackoverflow.com/questions/47632706/immutable-struct-in-golang