50 个州的每一个都印刷了不同的设计。其他的硬币都没有这种区分州的设 计，所以只有这些 25 美分硬币有特殊的价值。可以将这些信息加入我们的 enum，通过改变 Quarter 变体来包含一个 State 值，示例 6-4 中完成了这些修改： #[derive(Debug)] // 这样可以立刻看到州的名称 enum UsState { Alabama, Alaska, // 以将其加入收藏。 在这些代码的匹配表达式中，我们在匹配 Coin::Quarter 变体的分支的模式中增加了一个叫做 state 的变量。当匹配到 Coin::Quarter 时，变量 state 将会绑定 25 美分硬币所对应州的值。 接着在那个分支的代码中使用 state，如下： fn value_in_cents(coin: Coin) -> u8 { match coin { Coin::Nickel => 5, Coin::Dime => 10, Coin::Quarter(state) => { println!("State quarter from {state:?}!"); 123/562Rust 程序设计语言 简体中文版 25 } } } 如果调用

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x, y) x normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually

connection is that regular expressions are themselves input as strings, which are parsed into a state ma- chine that can be used to efficiently search for patterns in strings. In Julia, regular expressions functions are not pure mathematical functions, because they can alter and be affected by the global state of the program. The basic syntax for defining functions in Julia is: julia> function f(x,y) x + normal code blocks. There are many possible uses quite different from map, such as managing system state. For example, there is a version of open that runs code ensuring that the opened file is eventually