其实可以看到,这里宏的定义和我们上面定义宏的方式是不一样的,没有所谓的TokenStream出现,而是通过macro_rules!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。
简单来说, 过程宏的语法格式基本是: macro_rules! <macro_name> { <pattern1> => { <expansion1> }; <pattern2> => { <expansion2> }; ... } 更详细的可以参考https://doc.rust-lang.org/reference/macros-by-example.html这里直接给出了过程宏定义的文法 每个过程宏都有一个名称, 以及若干个规则...
The argument(s) of a macro are prefixed by a dollar sign $ and type annotated with a designator.Rust will try to match the patterns defined within the match rules. In the above example our rule is:($message:expr) => { println!("{}", $message) };...
Let's look at an example of a simple macro that defines a new function to print "Hello, World!". // A simple macro named `hello_world`macro_rules!hello_world {// `()` indicates that the macro takes no argument() => {// The macro will expand into the contents of this blockprintln!
macro Rust 也有 宏系统 (macro), 不是类似 C 的那种简单文本替换的宏,而是类似 Lisp 系语 言的宏,使用过 Lisp 方言的同学自然会明白宏的强大,《黑客与画家》的作者 Paul Gram 也是宏的忠实粉丝。比如我使用宏来创建一个函数: 代码语言:javascript
在Rust源代码中,rust-analyzer工具的mbe(Macro by Example)crate中的syntax_bridge.rs文件的作用是提供宏展开的语法桥接功能。具体来说,它定义了一些结构体、枚举和trait,用于处理句法的建模和转换。 首先,让我们了解以下几个结构体的作用: SyntheticTokenId:一个公共结构体,包含了合成令牌(SyntheticToken)的标识符,以...
The original Little Book of Rust Macros has helped me immensely with understanding Macros by Example style 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...
Linq-in-Rust - Macro and methods for C#-LINQ-like expressions. Markup language CommonMark pulldown-cmark/pulldown-cmark - CommonMark parser insomnimus/tidier [tidier] - A library to format HTML, XHTML and XML documents. Mobile Android / iOS ivnsch/rust_android_ios - An example of ...
构建集成测试时会设置CARGO_BIN_EXE_<name>环境变量<https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>以便它可以使用env宏<https://doc.rust-lang.org/std/macro.env.html>来定位可执行文件。传递目标选择标志将只构建指定的目标。注意--bin、-...
macro_rules!calculate {//单个 'eval' 模式(eval $e:expr) =>{ let val: usize= $e;//强制类型为整形println!("{} = {}", stringify!{$e}, val); };//递归的拆解多重 'eval'(eval $e:expr, $(eval $es:expr),+) =>{ calculate!{eval $e} ...