面试题：Rust中match表达式针对枚举类型的模式匹配应用

Question

假设我们有如下枚举类型： ```rust enum TrafficLight { Red, Yellow, Green } ``` 请使用`match`表达式实现一个函数`traffic_light_action`，当输入为`TrafficLight::Red`时返回字符串`"Stop"`，`TrafficLight::Yellow`时返回`"Prepare to stop"`，`TrafficLight::Green`时返回`"Go"`。

Answer 1

enum TrafficLight {
    Red,
    Yellow,
    Green
}

fn traffic_light_action(light: TrafficLight) -> &'static str {
    match light {
        TrafficLight::Red => "Stop",
        TrafficLight::Yellow => "Prepare to stop",
        TrafficLight::Green => "Go"
    }
}