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<main>
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<h2 id="附录-d实用开发工具"><a class="header" href="#附录-d实用开发工具">附录 D：实用开发工具</a></h2>
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<!-- https://github.com/rust-lang/book/blob/main/src/appendix-04-useful-development-tools.md -->
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<!-- commit 56ec353290429e6547109e88afea4de027b0f1a9 -->
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<p>在本附录中，我们将讨论 Rust 项目提供的一些有助于开发 Rust 代码的工具。我们将介绍自动格式化、快速应用警告修复、linter 以及与 IDE 的集成。</p>
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<h3 id="通过-rustfmt-自动格式化"><a class="header" href="#通过-rustfmt-自动格式化">通过 <code>rustfmt</code> 自动格式化</a></h3>
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|
<p><code>rustfmt</code> 工具根据社区代码风格格式化代码。很多项目使用 <code>rustfmt</code> 来避免编写 Rust 代码风格的争论：所有人都用这个工具格式化代码！</p>
|
|
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<p>安装 <code>rustfmt</code>：</p>
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|
|
<p>Rust 安装默认已包含 rustfmt，因此你的系统上应该已经有 <code>rustfmt</code> 和 <code>cargo-fmt</code> 程序了。这两个命令类似于 <code>rustc</code> 和 <code>cargo</code>，其中 <code>rustfmt</code> 提供了更细粒度的控制，而 <code>cargo-fmt</code> 则理解使用 Cargo 的项目约定。要格式化任何 Cargo 项目，请输入以下命令：</p>
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<pre><code class="language-sh">$ cargo fmt
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|
|
</code></pre>
|
|
|
<p>运行此命令会格式化当前 crate 中所有的 Rust 代码。这应该只会改变代码风格，而不是代码语义。</p>
|
|
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<p>该命令会为你提供 <code>rustfmt</code> 和 <code>cargo-fmt</code>，类似于 Rust 同时提供 <code>rustc</code> 和 <code>cargo</code>。要格式化任何 Cargo 项目，请执行以下命令：</p>
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|
|
<pre><code class="language-console">$ cargo fmt
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|
|
</code></pre>
|
|
|
<p>运行此命令会格式化当前 crate 中所有的 Rust 代码。这应该只会改变代码风格，而不是代码语义。有关 <code>rustfmt</code> 的更多信息，请参阅 <a href="https://github.com/rust-lang/rustfmt">该文档</a>。</p>
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<h3 id="通过-rustfix-修复代码"><a class="header" href="#通过-rustfix-修复代码">通过 <code>rustfix</code> 修复代码</a></h3>
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|
|
<p><code>rustfix</code> 工具已随 Rust 安装一并提供，可以自动修复那些具有明确修复方式的编译器警告，这通常正是你所需要的。你可能已经见过类似的编译器警告。例如，考虑如下代码：</p>
|
|
|
<p><span class="filename">文件名：src/main.rs</span></p>
|
|
|
<pre class="playground"><code class="language-rust edition2024">fn main() {
|
|
|
let mut x = 42;
|
|
|
println!("{x}");
|
|
|
}</code></pre>
|
|
|
<p>这里定义变量 <code>x</code> 为可变，但是我们从未修改它。Rust 会警告说：</p>
|
|
|
<p>这里调用了 <code>do_something</code> 函数 100 次，不过从未在 <code>for</code> 循环体中使用变量 <code>i</code>。Rust 会警告说：</p>
|
|
|
<pre><code class="language-console">$ cargo build
|
|
|
Compiling myprogram v0.1.0 (file:///projects/myprogram)
|
|
|
warning: variable does not need to be mutable
|
|
|
--> src/main.rs:2:9
|
|
|
|
|
|
|
2 | let mut x = 0;
|
|
|
| ----^
|
|
|
| |
|
|
|
| help: remove this `mut`
|
|
|
|
|
|
|
= note: `#[warn(unused_mut)]` on by default
|
|
|
</code></pre>
|
|
|
<p>警告中建议移除 <code>mut</code> 关键字。我们可以通过运行 <code>cargo fix</code> 命令使用 <code>rustfix</code> 工具来自动采用该建议：</p>
|
|
|
<pre><code class="language-console">$ cargo fix
|
|
|
Checking myprogram v0.1.0 (file:///projects/myprogram)
|
|
|
Fixing src/main.rs (1 fix)
|
|
|
Finished dev [unoptimized + debuginfo] target(s) in 0.59s
|
|
|
</code></pre>
|
|
|
<p>如果再次查看 <em>src/main.rs</em>，会发现 <code>cargo fix</code> 修改了代码：</p>
|
|
|
<p><span class="filename">文件名：src/main.rs</span></p>
|
|
|
<pre class="playground"><code class="language-rust edition2024">fn main() {
|
|
|
let x = 42;
|
|
|
println!("{x}");
|
|
|
}</code></pre>
|
|
|
<p>变量 <code>x</code> 现在是不可变的了，警告也不再出现。</p>
|
|
|
<p><code>cargo fix</code> 命令可以用于在不同 Rust 版本间迁移代码。版本在<a href="appendix-05-editions.html">附录 E</a>中介绍。</p>
|
|
|
<h3 id="使用-clippy-获取更多-lint"><a class="header" href="#使用-clippy-获取更多-lint">使用 Clippy 获取更多 lint</a></h3>
|
|
|
<p>Clippy 工具是一组 lints 的集合，用于分析你的代码，帮助你捕捉常见错误并改进 Rust 代码。Clippy 已包含在 Rust 的标准安装中。</p>
|
|
|
<p>要对任何 Cargo 项目运行 Clippy 的 lint，请输入以下命令：</p>
|
|
|
<pre><code class="language-console">$ cargo clippy
|
|
|
</code></pre>
|
|
|
<p>例如，你编写了一个程序使用了数学常数，例如 pi，的一个近似值，如下所示，：</p>
|
|
|
<p><span class="filename">文件名：src/main.rs</span></p>
|
|
|
<pre class="playground"><code class="language-rust edition2024">fn main() {
|
|
|
let x = 3.1415;
|
|
|
let r = 8.0;
|
|
|
println!("the area of the circle is {}", x * r * r);
|
|
|
}</code></pre>
|
|
|
<p>在此项目上运行 <code>cargo clippy</code> 会导致这个错误：</p>
|
|
|
<pre><code class="language-text">error: approximate value of `f{32, 64}::consts::PI` found
|
|
|
--> src/main.rs:2:13
|
|
|
|
|
|
|
2 | let x = 3.1415;
|
|
|
| ^^^^^^
|
|
|
|
|
|
|
= note: `#[deny(clippy::approx_constant)]` on by default
|
|
|
= help: consider using the constant directly
|
|
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#approx_constant
|
|
|
</code></pre>
|
|
|
<p>该错误提示你 Rust 已经定义了一个更精确的 <code>PI</code> 常量，如果使用该常量，你的程序会更为正确。你可以将代码改为使用 <code>PI</code> 常量。如下代码就不会引发 Clippy 的任何错误或警告：</p>
|
|
|
<p><span class="filename">文件名：src/main.rs</span></p>
|
|
|
<pre class="playground"><code class="language-rust edition2024">fn main() {
|
|
|
let x = std::f64::consts::PI;
|
|
|
let r = 8.0;
|
|
|
println!("the area of the circle is {}", x * r * r);
|
|
|
}</code></pre>
|
|
|
<p>有关 Clippy 的更多信息，请参阅 <a href="https://github.com/rust-lang/rust-clippy">其文档</a>。</p>
|
|
|
<h3 id="使用-rust-analyzer-的-ide-集成"><a class="header" href="#使用-rust-analyzer-的-ide-集成">使用 <code>rust-analyzer</code> 的 IDE 集成</a></h3>
|
|
|
<p>为了帮助 IDE 集成，Rust 社区建议使用 <a href="https://rust-analyzer.github.io"><code>rust-analyzer</code></a>。这个工具是一组以编译器为中心的实用程序，它实现了 <a href="http://langserver.org/">Language Server Protocol</a>，一个 IDE 与编程语言之间的通信规范。<code>rust-analyzer</code> 可以用于不同的客户端，比如 <a href="https://marketplace.visualstudio.com/items?itemName=rust-lang.rust-analyzer">Visual Studio Code 的 Rust analyzer 插件</a>。</p>
|
|
|
<p>访问 <code>rust-analyzer</code> 项目的<a href="https://rust-analyzer.github.io">主页</a>来了解如何安装它，然后为你的 IDE 安装 language server 支持。如此你的 IDE 便会获得如自动补全、跳转到定义和 inline error 之类的功能。</p>
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