Golang中的不可变结构

Question

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.

Answer 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