:: 和 .在锈? [英] What is the difference between :: and . in Rust?

问题描述

我对 :: 和 . 之间的区别感到困惑.除了语法不同之外，它们看起来相同.

<块引用>

let mut guess = String::new();io::stdin().read_line(&mut 猜测).expect("读取行失败");

"编写猜谜游戏" 来自 Rust 编程语言

在上面的例子中，我访问了 String 中的函数 new().String::new() 和 String.new() 有什么区别?. 仅用于方法吗?

解决方案

. 用于在左侧有值时.:: 当你有一个类型或模块时使用.

或者:.用于值成员访问，::用于命名空间成员访问.

I am confused by the difference between :: and .. They look the same except that their syntax are different.

let mut guess = String::new();

io::stdin().read_line(&mut guess)
    .expect("Failed to read line");

"Programming a Guessing Game" from The Rust Programming Language

In the above case, I access the function new() in String. What is the difference between String::new() and String.new()? Is . only for methods?

解决方案

. is used when you have a value on the left-hand-side. :: is used when you have a type or module.

Or: . is for value member access, :: is for namespace member access.

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