enum_parser_helper!($($tt)*) } }; } 三种情况,加空enum的情况都匹配到了,虽然=>右边的{}里面还没填东西,但是大体的形状是对的。好像也不比struct复杂多少嘛, 测试一下 enum_parser! {enumE{} } duang error!!! error: expected oneof`(`,`,`,`=`,`{`, or`}`, found`!`--> src/main....
Here, we have initialized the values of thename,ageandheightfields of the Person struct. This process of initializing the values of struct fields is known as aninstantiation of a struct. Note:The struct definition is a template, and the struct instances fill in that template with data. Access...
S这个Struct是一个包含一个字段的结构体,字段的类型为u32。 Tup(u8, C)这个Struct是一个参数化的结构体,它有两个字段,一个是u8类型的字段,另一个是C类型的字段。 Traits Foo这个Trait是一个占位Trait,没有方法和默认实现,可以用来作为其它Trait的约束或用作类型占位符。 Enums En这个Enum是一个简单的枚举类...
总之,rust/library/core/src/num/mod.rs文件是Rust标准库中num模块的入口文件,定义了各种数值类型的基本操作和算法,以及一些用于数值解析和浮点数分类的trait和enum。 File: rust/library/core/src/bool.rs 在Rust源代码中,rust/library/core/src/bool.rs文件的作用是定义了Rust中的bool类型以及与其相关的操作、方...
enumMessage { Quit, Move { x: i32, y: i32 }, Write(String), ChangeColor(i32, i32, i32), } This enum has four variants with different types: Quithas no data associated with it at all. Moveincludes an anonymous struct inside it. ...
enum Food { Cake, Pizza, Salad } #[derive(Debug)] struct Bag { food: Food } fn main() { let bag = Bag { food: Food::Cake }; match bag.food { Food::Cake => println!("I got cake"), ref a => println!("I got {:?}", a) ...
enum Food { Cake, Pizza, Salad } #[derive(Debug)] struct Bag { food: Food } fn main() { let bag = Bag { food: Food::Cake }; match bag.food { Food::Cake => println!("I got cake"), a => println!("I got {:?}", a) ...
enum Food { Cake, Pizza, Salad } #[derive(Debug)] struct Bag { food: Food } fn main() { let bag = Bag { food: Food::Cake }; match bag.food { Food::Cake => println!("I got cake"), a => println!("I got {:?}", a) ...
强制处理所有的 input 模式:enum 和模式匹配 (match) 让你可以处理所有可能的情况,不会有漏掉的情况。 它具备写内核的特性:packed struct[23],raw pointers[24],改进的内联汇编语法[25],embedding assembly files[26]等等。
#![feature(const_fn)] pub enum A { B, C, } const fn foo(a: A) { match a { A::B => (), A::C => (), } } fn main() {} playpen: https://is.gd/n7pDFb rustc 1.17.0-nightly (e703b33e3 2017-03-23) error: internal compiler error: /checkout/src/li...