这个int值对应到rust的discriminant,用于区分enum变量,对于非simple enum变量,运行时对应一个struct值{int, tp},这个struct的第0个元素就会绑定discriminant,第二个元素为enum元素的具体值,例如some(array[int]{1,2,3})运行时对应{1, &[1,2,3]},discriminant值1代表some为option enum的第1个元素,位于none之后,...
RFC PR:rust-lang/rfcs#2195 Rust Issue: N/A 总览 有意识的为Rust enum标记#[repr(u32, i8, etc..)]和#[repr(C)]就能让其拥有固定的内存布局。这个功能有两个目的: 允许Rust底层根据其布局直接初始化enum内容,允许C安全的与之交互。 文章目的 enum对于数据储存很方便使用,可惜其内存布局被故意的设计为...
枚举类型enum 枚举类型是一种用于表示一组有限数量相互关联的离散型数据,这些值可以是不同的整数、字符串或其他类型的对象。枚举体内的元素称作“成员”,rust语言中,枚举里面的成员,都可以被看作是结构体,当然枚举还能嵌套另一个枚举。 定义和声明 在Rust中,枚举类型可以通过关键字enum来定义: enum MyEnum {Variant...
To do this kind of thing, you need what's known as a tt-muncher macro: It builds all of the text for the enum body first, and then wraps it in the enum as the final step. A good reference for this kind of advanced macro programming is The Little Book of Rust Macros. 大意是: ...
Rust:https://doc.rust-lang.org/book/enums.html Currently, a developer can copy the code from the Python docs into his or her project, or add a dependency on aenum. I would argue that it belongs in the standard library. If there are objections to it being too magical, I would argue...
【Rust日报】2020-11-23 使用 Enums 来减少内存使用 使用Enums 来减少内存使用 Enum 在不存储真正数据的时候,仅仅需要1byte就可以代表多种状态. 根据这个特性, 作者把一些特殊场景下的内存使用大大降低了. 原文链接:Decrease Memory Using Enums in Rust | DOM Events...
publicclassEnumToIntExample{// Enum representing days of the weekpublicenumDaysOfWeek{SUNDAY,MONDAY,TUESDAY,WEDNESDAY,THURSDAY,FRIDAY,SATURDAY;}publicstaticvoidmain(String[]args){// Converting an enum constant to int using ordinal()intdayIndex=DaysOfWeek.WEDNESDAY.ordinal();// Displaying the resultSyste...
This method involves casting the integer directly to the enum type, assuming the integer value corresponds to a valid enum value. The syntax for direct casting an integer to an enum in C# is as follows: YourEnumType enumVariable = (YourEnumType)intValue; Here, YourEnumType represents the ...
to_string(), Self::Clubs => "Black".to_string(), Self::Spades => "Black".to_string(), } } } (The capitalized Self in this case is an implicit alias to Suit.) Further reading: https://doc.rust-lang.org/rust-by-example/custom_types/enum.html Kotlin Kotlin also has not one ...
We will take this example as the base structure and try to achieve the same results in Rust: class Person { void work() { println("Working hard"); } void sleep() { println("Sleeping 8 hours"); } int age; String name; } class Teacher extends Person { void work() { println("...