Rust 最常用的宏形式是声明宏(declarative macros)。它们有时也被称为 “macros by example”、“macro_rules! 宏” 或者就是 “macros”。其核心概念是,声明宏允许我们编写一些类似 Rust match 表达式的代码。宏也将一个值和包含相关代码的模式进行比较;此种情况下,该值是传递给宏的 R
这种声明式定义的语法来定义的。这其实就是声明式宏 也叫做宏,更原味的叫法是macros by example. 声明式宏,我会在下篇文章写怎么使用,怎么自定义一个自己的宏。
Macros can also take arguments, which allows us to customize the code that it generates based on different inputs. For example, here's a macro that defines a function to print a custom message: // A macro named `print_message`macro_rules!print_message {// Match rule that takes an argum...
这也是rust的宏是 Hygienic Macros 的体现。 // 而 C/C++ 的宏不强制要求,但是如果遇到代码片段,在 C/C++ 中也应该使用{}包裹起来。 { let mut v = std::vec::Vec::new(); $(v.push($el);)* v } }; // 匹配 my_vec![1; 3] ($el:expr; $n:expr) => { std::vec::from_elem($...
For example, fn main() { print!("Rust is fun! "); print!("I love Rust programming."); } Output Rust is fun! I love Rust programming. You can see we have used two print! macros to print two different strings. However, both the strings are printed in the same line. To separate...
...当前,:pat不匹配|,因为在 Rust 1.53 之前,并非所有模式(在所有嵌套级别)都可以包含|。接受像A | B这样的模式的宏,例如`match!()`[15]使用类似(_:pat)|+的东西。...[14] macro_rules宏: https://doc.rust-lang.org/stable/reference/macros-by-example.html [15] match!
Theoriginal Little Book of Rust Macroshas helped me immensely with understandingMacros by Examplestyle macros while I was still learning the language. Unfortunately, the original book hasn't been updated since April of 2016, while the Rust language as well as its macro-system keeps evolving. Whic...
"Macros By Example" - The Rust Reference To use this crate, you do not need to know how macros are defined. Trait In Rust, traits are a way of defining a generalized property. They should be thought of expressing what a type is capable of doing. For example: if a type implementsInto...
Macros Multiple pattern rules Repetitions Optional quantifier Summary Starting with SDL Understanding Rust crates Installing SDL2 Installing SDL2 on Linux Installing SDL2 on Mac Installing SDL2 on Windows Windows with Build Script Windows (MinGW) Windows (MSVC) Setting up your Rust project Cargo and ...
Rust uses trait-based generics and macros for metaprogramming. While less powerful than C++ templates in some aspects, Rust offers a more unified and often more readable approach to generic programming. Error handling Rust uses the Result type for error handling, encouraging explicit error checking ...