如何匹配具有多个字段的选项?

时间:2014-07-24 21:02:59

标签: pattern-matching rust

如何匹配具有多个字段的选项?我有以下代码:

let opt_windowrecv = glfw_context.create_window(1280, 720, "Hello World!", glfw::Windowed); // returns Option<(Window, Receiver<(f64, WindowEvent)>)>

let window = match opt_windowrecv { // Does not compile
    Some(window, _) => window,
    None            => return
};

抱怨说:

  

此模式有2个字段,但相应的变体有1个字段

使用此解决方法确实有效:

let opt_windowrecv = glfw_context.create_window(1280, 720, "Hello World!", glfw::Windowed); // returns Option<(Window, Receiver<(f64, WindowEvent)>)>

let windowrecv = match opt_windowrecv {
    Some(windowrecv) => windowrecv,
    None            => return
};

let (window, _) = windowrecv;

我做错了什么,或者这是Rust编译器中的错误?我正在使用glfw-rs library

1 个答案:

答案 0 :(得分:6)

let window = match opt_windowrecv {
    Some((window, _)) => window,
    None            => return
};

应该有效。 Some的解构应该是一个元组,而不是两个参数。