英文:
Is there a constructor interface for a struct type?
问题
在golang中，假设我有一个类型，在使用之前需要进行一些设置，而不仅仅是设置默认值。例如：
type dice struct {
input string
count int
sides int
result int
}
func (d *dice) Roll() {
// 初始化随机种子
rand.Seed(time.Now().UnixNano())
for i := 0; i < d.count; i++ {
d.result = d.result + rand.Intn(d.sides)+1)
}
}
这只是一个简单的例子，但是如果我想在创建dice类型的实例时自动调用d.Roll()，有没有办法做到这一点？更符合我要解决的问题，假设我想在调用Roll()之前自动调用rand.Seed(time.Now().UnixNano())，有没有一种符合golang惯例的方法来实现这个？
基本上，我的问题是“如何在golang中处理构造函数功能？”是否有一个接口可以添加？
英文:
In golang, say I have a type that needs some setup done on it before use beyond just setting default values. ex:
type dice struct {
input string
count int
sides int
result int
}
func (d *dice) Roll() {
//initialize random seed
rand.Seed(time.Now().UnixNano())
for i := 0; i < d.count; i++ {
d.result = d.result + rand.Intn(d.sides)+1)
}
}
Simple example but say if I wanted to have d.Roll() called automatically when creating an instance of the 'dice' type is there a way to do that? More in line with the issue I'm trying to solve, say I wanted the rand.Seed(time.Now().UnixNano()) bits to be called automatically before I call Roll() is there an idiomatic golang way to do this?
Basically "How do you handle constructor functionality in golang?" is my question. Is there an interface for this I can add?
答案1
得分: 1
不，Go语言不提供这种类型的接口。你不能像在C++中那样使用构造函数。
目前的惯用方式是创建一个函数：
func NewX(args...) X // 或 *X
在这个函数中，你可以按照你的需求设置结构体。在你的情况下，可以像这样编写：
func NewDice() dice {
var d dice
d.Roll()
return d
}
英文:
No, Go doesn't provide this kind of interface. You just can't use a constructor like you would do in C++ by example.
The current idiom is to create a function
NewX(args...) X // or *X
in which you can setup your struct as you want. In your case, it could look like this:
func NewDice() dice {
var d dice
d.Roll()
return d
}
答案2
得分: 0
没有。但是常见的、我会说是惯用的做法是在你的包中放置一个 func NewDice() dice，然后你可以直接调用它来获取一个实例。在那里进行设置。它的作用与构造函数相同。在包级别上拥有像 NewMyType 这样的方法来进行初始化并返回一个实例是相当常见的。
英文:
There is not. But the common, and I would say idiomatic, thing to do is to put a func NewDice() dice in your package and then you can just call it to get an instance. Do your set up there. It serves the same purpose as a constructor. It's pretty common to have package level methods like NewMyType that do initilization and return and instance.
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