对go语法感到困惑 [英] Confused about go syntax

问题描述

与此代码有些混淆.

var _ QueryAppender = (*selectQuery)(nil)

我在 pg-go 存储库，不知道为什么 QueryAppender 这样声明.请向我解释以这种方式声明变量的用例是什么.

I found this code in pg-go repository and don't know why QueryAppender declared that way. Please explain me what is the use cases when I should declare variables that way.

推荐答案

这在运行时不会执行任何操作，但是除非 * selectQuery 类型满足接口 QueryAppender ，编译将失败.这是一种静态断言.

This doesn't do anything at runtime, but unless the *selectQuery type satisfies the interface QueryAppender, compilation will fail. It's a kind of static assertion.

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