惯用的golang：访问和更新结构中的项目

Question

So I am trying to write some code that allows me to edit values in an array in a struct. This example uses "Status" as a possible value to alter, but this is just a simplification to try to get my intent across.

package main

import(
  "fmt"
)

type Parent struct {
  Children []Child
}

type Child struct {
  Status string
}

func (p *Parent) Add() *Child {
  var child Child
  child.Status = "1"
  p.Children = append(p.Children, child)
  return &p.Children[len(p.Children)-1]
}

func main() {
  var p Parent
  child := p.Add()
  child.Status = "2"
  fmt.Println(p)
  fmt.Println(child)
}

This doesn't feel "proper". How should I do this in golang? Certainly I could pass the value in as a parameter, but in my particular case I would like to edit function pointers that are inside the Child struct (not in this code to keep it short) after having added the child. That feels nicer, but maybe I just need to pass them as parameters to the Add method?

eg

func (p *Parent) Add(fn1 func(), fn2 func()) *Child {

Anyway just wondering if anybody has any thoughts on this type of situation.

Answer 1

I think you should create the Child outside of the Add method and pass it in. If you want to manipulate the Child, do that before you passed it in. You might use methods on the Child struct to do that:

func (c *Child) Init(fn1 func(), fn2 func()) {
  c.Status = "1"
  ...
}

func (p *Parent) Add(c *Child) *Child {
  p.Children = append(p.Children, c)
  return c
}

func main() {
  var p Parent
  var child Child
  child.Init(...)       // <- pass something in there...
  p.Add(&child)
  child.Status = "2"
  fmt.Println(p)
  fmt.Println(child)
}