macro_rules!vec_strs{($($element:expr)// 重复的内容是元变量,类型为表达式,// 分隔符*// 匹配0个或者多个)=>{{letmutv=Vec::new();$(v.push(format!("{}",$element));)*// 重复性的将匹配到的$element以字符串的形式存入到vec中v// 最终展开产物}};}fnmain(){lets=vec_strs![1,"a",...
baz{($e:expr)=>{println!("baz expr: {}",$e);};($l:literal)=>{println!("baz literal: {}",$l);}}fnmain(){foo!(1);foo!(1+2);bar!(1);bar!(1+2);baz!(1);baz!(1+2);}// Output:// foo expr: 1// foo expr: 3// bar literal: 1// bar expr: 3// baz expr: ...
foo { ($e:expr) => {println!("foo expr: {}", $e); }; }macro_rules!bar{ ($l:literal) => {println!("bar literal: {}", $l); }; ($e:expr) => {println!("bar expr: {}", $e); }; }macro_rules!baz { ($e:expr) => {println!("baz expr: {}", $e); }; ($l...
```rust,skt-foo let p =PathBuf::from("foo");println!("{:?}", p);``` This tells skeptic to look in the template file for another markdown block with the sameskt-fooannotation, and compose them together using the standard Rustformat!macro. Here's what the template looks like: ...
println!("{}", x) Print x using DisplaySTD on std. out and append new line. '15 🗑️ println!("{x}") Same, but use variable x from scope. '21 format!("{a:.3} {b:?}") Convert a with 3 digits, add space, b with Debug STD, return String. '21Tooling...
Templates are Rust format specifiers that must take a single argument (i.e. they need to contain the string "{}"). See the (old) template example for more on templates. Note that in a template, real braces need to be doubled. The old-style, document-global template Within a document...
println!("{:?}", p); ``` ``` This tells skeptic to look in the template file for another markdown block with the sameskt-fooannotation, and compose them together using the standard Rustformat!macro. Here's what the template looks like: ...
strings are calledformat strings, while the"{}"in the string are calledformat specifiers. For printing simple types such as primitives, we can use the"{}"format specifier, whereas for other types, we use the"{:?}"format specifier. There are more details to this, though. Whenprintln!encoun...
/// ```no_run /// loop { /// println!("Hello, world"); /// } /// ``` compile_fail 告诉rustdoc 应该编译失败。如果便已通过,测试失败。但是需要注意现在版本 Rust 编译失败可能在将来 Rust 版本编译成功。/// ```compile_fail /// let x = 5; /// x += 2; // shouldn't compile...
我们前面理论刚了解过这个Fragment Specifiers的几种类型,但只是浅尝即止,接下来让我们来更直观点了解这14种类型。 注意:使用ident、lifetime和tt片段以外的任何内容进行捕获将使捕获的AST不透明,从而无法在将来的宏调用中将其与其他片段说明符进一步匹配。