Clone, PartialEq)] pub enum Number { I64(i64), F64(f64), } #[derive(Debug, PartialEq, Clone)] pub enum Value { String(String), Number(Number), Boolean(bool), Array(Vec<Value>), Object(HashMap<String, Value>), Null, }
enum 关键字允许创建一个从数个不同取值中选其一的枚举类型。 enumCell{// 成员可以是单元结构体NULL,// 也可以是元组结构体,如果 () 里面没有指定类型,那么就是空的元组结构体Integer(i64),Floating(f64),DaysSales(u32,u32,u32,u32,u32),// 普通结构体,或者说 C 风格结构体// 如果 {} 里面没有...
/// Encapsules all supported (logical) data types in the system.#[derive(Debug)]pubenumDataType{/// Corresponding to Int16 physical typeSmallInt,/// Corresponding to Int32 physical typeInteger,/// Corresponding to Int64 physical typeBigInt,/// Corresponding to String physical typeVarchar,///...
enumWebEvent{// 一个 `enum` 可以是单元结构体(称为 `unit-like` 或 `unit`),PageLoad, PageUnload,// 或者一个元组结构体,KeyPress(char),Paste(String),// 或者一个普通的结构体。Click { x:i64, y:i64} } 访问枚举值 // 方法一:WebEvent::PageLoad// 方法二:useWebEvent::{PageLoad};//...
[allow(unused)]fn main() {struct TextMatch(usize, String); let m = TextMatch(12, "needle".to_owned()); assert_eq!(m.0, 12);} 这让我们来到了 Rust 类型系统的皇冠上的宝石:枚举(enum)。 在其基本形式中,很难看出有什么值得兴奋的。与其他语言一样,枚举允许你指定一组互斥的值,可能附带一...
从字符串转换:EnumString 从u8转换:FromRepr (如果添加了#[repr(u8)],则可以仅使用as u8转换为u8) 有关其他选项,请参阅这些现有答案: How do I get an enum as a string? Can I convert a string to enum without macros in Rust? How do I match enum values with an integer? 2#mnemlml8 2022-...
letx=42i32;// Integer literal with type suffixlety:i64=x; error[E0308]:mismatched types-->use-types/src/main.rs:23:22|23|lety:i64=x;|---^expected `i64`,found `i32`|||expected due to this|help:you can convert an `i32` to an `i64`|23|lety:i64=x.into();|+++++ 在这里...
How can I convert a C-style enum to an integer, or vice-versa? Converting a C-style enum to an integer can be done with an as expression, like e as i64 (where e is some enum). Converting in the other direction can be done with a match statement, which maps different numeric va...
To do this in Rust, you need to implement theErrortrait for your custom error type. Thestd::error::Error traitrepresents the basic expectations for error values and allows us to convert ourEnumorStructto anErrtype. TheErrortrait requires you to implementDisplayandDebugtrait for your ownErrorty...
Transport (bit-banging or SPI) agnostic, but can convert Set 2 Scancodes into Unicode. qei : A qei wrapper that allows you to extend your qei timers from a 16-bit integer to a 64-bit integer. - qemu-exit: Quit a running QEMU session with user-defined exit code. Useful for unit...