带有下划线，内联接口和赋值的变量声明是什么？ [英] What is this variable declaration with underscore, inline interface and assignment?

问题描述

Go代码的这段代码是做什么的？

  var _ interface {
 add（string）error 
} =& watchcher {} 
  

我相信& watchcher {} 返回两件事情，第一件被丢弃，第二件被分配...接口？我在Github上找到了 fswatch 中的代码。

解决方案

此构造将声明一个变量，其中包含空格标识符，其类型由类型文字给出;这种情况下的接口定义。以下是初始化表达式 - 在这种情况下指向复合文本的指针。

片段的总体功能是静态确保 *观察者满足所述接口，因为 _ 变量没有以任何方式实现，只能观察到初始值设定项的任何可能的副作用。无论是静态的（在这种情况下）还是动态的（例如调用一个在运行时分配的函数，比如某些全局变量，注册一个处理程序等）。

What does this snippet of Go code do?

var _ interface {
    add(string) error
} = &watcher{}

I believe &watcher{} returns two things, the first is discarded and the second is assigned to ... an interface? I found the code in fswatch on Github.

解决方案

This construct will declare a variable with an blank identifier name with type given by a type literal; an interface definition in this case. What follows is in initializer expression - a pointer to a composite literal in this case.

Overall functionality of the snippet is to statically ensure that a *watcher satisfies the said interface as the _ variable is not materialized in any way and only any possible side effects of the initializer can be observed. Either static (as in this case) or dynamic (like e.g. calling a function which assigns at runtime to, say, some global vars, registers a handler, etc.)

这篇关于带有下划线，内联接口和赋值的变量声明是什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！