#define MAX(a, b) ((a) > (b) ? (a) : (b)) 我们也经常用宏实现泛型编程,像上面的,无关参数类型。也有如以下的复杂宏 #define EXPAND(x) x#define GET_MACRO(_1, _2, _3, _4, _5, _6, _7, _8, _9, NAME, ...) NAME#define PASTE(...) \EXPAND(GET_MACRO(__VA_ARGS__ _...
宏(也称为“声明式宏”或“模式宏”)和过程宏。本文主要是介绍Rust声明式宏的定义和使用,以及一些宏编程基本原理,帮助大家实现Rust宏编程入门。 一、获取关于宏 熟悉C语言的童鞋对宏不会陌生,比如定义一个取最小值的宏,类似这样: #define MIN(a, b) ((a) < (b) ? (a) : (b)) 应用该宏,取两个字...
#include<stdio.h>#defineADD(a,b)(a)+(b);intmain(){int a=10;int b=22;int _res=ADD(a,b)_res=ADD(a+1,b)_res=ADD(a*2,b+3)} 这样,我们在使用宏的时候,就避免了意外结果的发生。这样展开之后的代码如下所示: 代码语言:javascript 复制 intmain(){int a=10;int b=22;int _res=(a)...
//#[macro_use] define in 'root crate' or 'mod.rs' or 'main.rs'userbatis::rbdc::datetime::DateTime;#[derive(Clone, Debug, Serialize, Deserialize)]pubstructBizActivity{pubid:Option<String>,pubname:Option<String>,pubpc_link:Option<String>,pubh5_link:Option<String>,pubpc_banner_img:Optio...
$crate::try_migrate_toml_chain!(error: $err, chain: [$a, $($rest),+]) ); } This works, but is quite verbose. It gets even more verbose with 3 arguments. This leads me to my question. Question Is there an easy(er) to define a macro so the keyword-ish inputs can be position...
To define a lexer, use the lexer! macro.lexer! { fn take_token(tok: 'a) -> Token<'a>;First declare the name of the function, the name of the token you will be able to access within the lexer, and the return type of your lexer. You can also optionally declare a lifetime for ...
具体来说,define_type_foldable_and_lift首先通过宏ast_struct!定义了一系列语法树节点的结构体,这些结构体表示不同的类型和语法结构。然后给每个结构体实现了TypeFoldable的方法。这些方法根据具体的类型组织起来,通过递归调用TypeFoldable的方法实现类型的遍历和转换。
There is no way to do it in Rust, and you have to either write a macro, or use Option and explicitly pass None. @puentesdias 接受的的回答仍然是正确的答案。在Rust中没有办法这样做,你要么写一个宏,要么使用Option并显式的传递None。
Add a dependency on thebootloader_apicrate in your kernel'sCargo.toml. Your kernel binary should be#![no_std]and#![no_main]. Define an entry point function with the signaturefn kernel_main(boot_info: &'static mut bootloader_api::BootInfo) -> !. The function name can be arbitrary. ...
include/linux/compiler-gcc4.h:79:43: note: expanded from macro 'asm_volatile_goto' # define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) 1. 2. 3. 4. 5. 据C2Rust文档介绍,需要最新的libclang才能支持此语法。