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<ol class="chapter"><li class="chapter-item affix "><a href="../about-book.html">关于本书</a></li><li class="chapter-item affix "><a href="../into-rust.html">进入 Rust 编程世界</a></li><li class="chapter-item affix "><a href="../first-try/sth-you-should-not-do.html">避免从入门到放弃</a></li><li class="chapter-item affix "><a href="../community.html">社区和锈书</a></li><li class="spacer"></li><li class="chapter-item affix "><a href="../some-thoughts.html">Xobserve: 一切皆可观测</a></li><li class="chapter-item affix "><a href="../beat-ai.html">BeatAI: 工程师 AI 入门圣经</a></li><li class="chapter-item affix "><li class="part-title">Rust 语言基础学习</li><li class="spacer"></li><li class="chapter-item "><a href="../first-try/intro.html"><strong aria-hidden="true">1.</strong> 寻找牛刀，以便小试</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../first-try/installation.html"><strong aria-hidden="true">1.1.</strong> 安装 Rust 环境</a></li><li class="chapter-item "><a href="../first-try/editor.html"><strong aria-hidden="true">1.2.</strong> 墙推 VSCode!</a></li><li class="chapter-item "><a href="../first-try/cargo.html"><strong aria-hidden="true">1.3.</strong> 认识 Cargo</a></li><li class="chapter-item "><a href="../first-try/hello-world.html"><strong aria-hidden="true">1.4.</strong> 不仅仅是 Hello world</a></li><li class="chapter-item "><a href="../first-try/slowly-downloading.html"><strong aria-hidden="true">1.5.</strong> 下载依赖太慢了？</a></li></ol></li><li class="chapter-item "><a href="../basic/intro.html"><strong aria-hidden="true">2.</strong> Rust 基础入门</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/variable.html"><strong aria-hidden="true">2.1.</strong> 变量绑定与解构</a></li><li class="chapter-item "><a href="../basic/base-type/index.html"><strong aria-hidden="true">2.2.</strong> 基本类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/base-type/numbers.html"><strong aria-hidden="true">2.2.1.</strong> 数值类型</a></li><li class="chapter-item "><a href="../basic/base-type/char-bool.html"><strong aria-hidden="true">2.2.2.</strong> 字符、布尔、单元类型</a></li><li class="chapter-item "><a href="../basic/base-type/statement-expression.html"><strong aria-hidden="true">2.2.3.</strong> 语句与表达式</a></li><li class="chapter-item "><a href="../basic/base-type/function.html"><strong aria-hidden="true">2.2.4.</strong> 函数</a></li></ol></li><li class="chapter-item "><a href="../basic/ownership/index.html"><strong aria-hidden="true">2.3.</strong> 所有权和借用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/ownership/ownership.html"><strong aria-hidden="true">2.3.1.</strong> 所有权</a></li><li class="chapter-item "><a href="../basic/ownership/borrowing.html"><strong aria-hidden="true">2.3.2.</strong> 引用与借用</a></li></ol></li><li class="chapter-item "><a href="../basic/compound-type/intro.html"><strong aria-hidden="true">2.4.</strong> 复合类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/compound-type/string-slice.html"><strong aria-hidden="true">2.4.1.</strong> 字符串与切片</a></li><li class="chapter-item "><a href="../basic/compound-type/tuple.html"><strong aria-hidden="true">2.4.2.</strong> 元组</a></li><li class="chapter-item "><a href="../basic/compound-type/struct.html"><strong aria-hidden="true">2.4.3.</strong> 结构体</a></li><li class="chapter-item "><a href="../basic/compound-type/enum.html"><strong aria-hidden="true">2.4.4.</strong> 枚举</a></li><li class="chapter-item "><a href="../basic/compound-type/array.html"><strong aria-hidden="true">2.4.5.</strong> 数组</a></li></ol></li><li class="chapter-item "><a href="../basic/flow-control.html"><strong aria-hidden="true">2.5.</strong> 流程控制</a></li><li class="chapter-item "><a href="../basic/match-pattern/intro.html"><strong aria-hidden="true">2.6.</strong> 模式匹配</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/match-pattern/match-if-let.html"><strong aria-hidden="true">2.6.1.</strong> match 和 if let</a></li><li class="chapter-item "><a href="../basic/match-pattern/option.html"><strong aria-hidden="true">2.6.2.</strong> 解构 Option</a></li><li class="chapter-item "><a href="../basic/match-pattern/pattern-match.html"><strong aria-hidden="true">2.6.3.</strong> 模式适用场景</a></li><li class="chapter-item "><a href="../basic/match-pattern/all-patterns.html"><strong aria-hidden="true">2.6.4.</strong> 全模式列表</a></li></ol></li><li class="chapter-item "><a href="../basic/method.html"><strong aria-hidden="true">2.7.</strong> 方法 Method</a></li><li class="chapter-item "><a href="../basic/trait/intro.html"><strong aria-hidden="true">2.8.</strong> 泛型和特征</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/trait/generic.html"><strong aria-hidden="true">2.8.1.</strong> 泛型 Generics</a></li><li class="chapter-item "><a href="../basic/trait/trait.html"><strong aria-hidden="true">2.8.2.</strong> 特征 Trait</a></li><li class="chapter-item "><a href="../basic/trait/trait-object.html"><strong aria-hidden="true">2.8.3.</strong> 特征对象</a></li><li class="chapter-item "><a href="../basic/trait/advance-trait.html"><strong aria-hidden="true">2.8.4.</strong> 进一步深入特征</a></li></ol></li><li class="chapter-item "><a href="../basic/collections/intro.html"><strong aria-hidden="true">2.9.</strong> 集合类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/collections/vector.html"><strong aria-hidden="true">2.9.1.</strong> 动态数组 Vector</a></li><li class="chapter-item "><a href="../basic/collections/hashmap.html"><strong aria-hidden="true">2.9.2.</strong> KV 存储 HashMap</a></li></ol></li><li class="chapter-item "><a href="../basic/lifetime.html"><strong aria-hidden="true">2.10.</strong> 认识生命周期</a></li><li class="chapter-item "><a href="../basic/result-error/intro.html"><strong aria-hidden="true">2.11.</strong> 返回值和错误处理</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/result-error/panic.html"><strong aria-hidden="true">2.11.1.</strong> panic! 深入剖析</a></li><li class="chapter-item "><a href="../basic/result-error/result.html"><strong aria-hidden="true">2.11.2.</strong> 返回值 Result 和?</a></li></ol></li><li class="chapter-item "><a href="../basic/crate-module/intro.html"><strong aria-hidden="true">2.12.</strong> 包和模块</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic/crate-module/crate.html"><strong aria-hidden="true">2.12.1.</strong> 包 Crate</a></li><li class="chapter-item "><a href="../basic/crate-module/module.html"><strong aria-hidden="true">2.12.2.</strong> 模块 Module</a></li><li class="chapter-item "><a href="../basic/crate-module/use.html"><strong aria-hidden="true">2.12.3.</strong> 使用 use 引入模块及受限可见性</a></li></ol></li><li class="chapter-item "><a href="../basic/comment.html"><strong aria-hidden="true">2.13.</strong> 注释和文档</a></li><li class="chapter-item "><a href="../basic/formatted-output.html"><strong aria-hidden="true">2.14.</strong> 格式化输出</a></li></ol></li><li class="chapter-item "><a href="../basic-practice/intro.html"><strong aria-hidden="true">3.</strong> 入门实战：文件搜索工具</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../basic-practice/base-features.html"><strong aria-hidden="true">3.1.</strong> 基本功能</a></li><li class="chapter-item "><a href="../basic-practice/refactoring.html"><strong aria-hidden="true">3.2.</strong> 增加模块化和错误处理</a></li><li class="chapter-item "><a href="../basic-practice/tests.html"><strong aria-hidden="true">3.3.</strong> 测试驱动开发</a></li><li class="chapter-item "><a href="../basic-practice/envs.html"><strong aria-hidden="true">3.4.</strong> 使用环境变量</a></li><li class="chapter-item "><a href="../basic-practice/stderr.html"><strong aria-hidden="true">3.5.</strong> 重定向错误信息的输出</a></li><li class="chapter-item "><a href="../basic-practice/iterators.html"><strong aria-hidden="true">3.6.</strong> 使用迭代器来改进程序(可选)</a></li></ol></li><li class="chapter-item "><li class="part-title">Rust 语言进阶学习</li><li class="spacer"></li><li class="chapter-item expanded "><a href="../advance/intro.html"><strong aria-hidden="true">4.</strong> Rust 高级进阶</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/lifetime/intro.html"><strong aria-hidden="true">4.1.</strong> 生命周期</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/lifetime/advance.html"><strong aria-hidden="true">4.1.1.</strong> 深入生命周期</a></li><li class="chapter-item "><a href="../advance/lifetime/static.html"><strong aria-hidden="true">4.1.2.</strong> &'static 和 T: 'static</a></li></ol></li><li class="chapter-item "><a href="../advance/functional-programing/intro.html"><strong aria-hidden="true">4.2.</strong> 函数式编程: 闭包、迭代器</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/functional-programing/closure.html"><strong aria-hidden="true">4.2.1.</strong> 闭包 Closure</a></li><li class="chapter-item "><a href="../advance/functional-programing/iterator.html"><strong aria-hidden="true">4.2.2.</strong> 迭代器 Iterator</a></li></ol></li><li class="chapter-item "><a href="../advance/into-types/intro.html"><strong aria-hidden="true">4.3.</strong> 深入类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/into-types/converse.html"><strong aria-hidden="true">4.3.1.</strong> 类型转换</a></li><li class="chapter-item "><a href="../advance/into-types/custom-type.html"><strong aria-hidden="true">4.3.2.</strong> newtype 和 类型别名</a></li><li class="chapter-item "><a href="../advance/into-types/sized.html"><strong aria-hidden="true">4.3.3.</strong> Sized 和不定长类型 DST</a></li><li class="chapter-item "><a href="../advance/into-types/enum-int.html"><strong aria-hidden="true">4.3.4.</strong> 枚举和整数</a></li></ol></li><li class="chapter-item "><a href="../advance/smart-pointer/intro.html"><strong aria-hidden="true">4.4.</strong> 智能指针</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/smart-pointer/box.html"><strong aria-hidden="true">4.4.1.</strong> Box堆对象分配</a></li><li class="chapter-item "><a href="../advance/smart-pointer/deref.html"><strong aria-hidden="true">4.4.2.</strong> Deref 解引用</a></li><li class="chapter-item "><a href="../advance/smart-pointer/drop.html"><strong aria-hidden="true">4.4.3.</strong> Drop 释放资源</a></li><li class="chapter-item "><a href="../advance/smart-pointer/rc-arc.html"><strong aria-hidden="true">4.4.4.</strong> Rc 与 Arc 实现 1vN 所有权机制</a></li><li class="chapter-item "><a href="../advance/smart-pointer/cell-refcell.html"><strong aria-hidden="true">4.4.5.</strong> Cell 与 RefCell 内部可变性</a></li></ol></li><li class="chapter-item "><a href="../advance/circle-self-ref/intro.html"><strong aria-hidden="true">4.5.</strong> 循环引用与自引用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/circle-self-ref/circle-reference.html"><strong aria-hidden="true">4.5.1.</strong> Weak 与循环引用</a></li><li class="chapter-item "><a href="../advance/circle-self-ref/self-referential.html"><strong aria-hidden="true">4.5.2.</strong> 结构体中的自引用</a></li></ol></li><li class="chapter-item "><a href="../advance/concurrency-with-threads/intro.html"><strong aria-hidden="true">4.6.</strong> 多线程并发编程</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/concurrency-with-threads/concurrency-parallelism.html"><strong aria-hidden="true">4.6.1.</strong> 并发和并行</a></li><li class="chapter-item "><a href="../advance/concurrency-with-threads/thread.html"><strong aria-hidden="true">4.6.2.</strong> 使用多线程</a></li><li class="chapter-item "><a href="../advance/concurrency-with-threads/message-passing.html"><strong aria-hidden="true">4.6.3.</strong> 线程同步：消息传递</a></li><li class="chapter-item "><a href="../advance/concurrency-with-threads/sync1.html"><strong aria-hidden="true">4.6.4.</strong> 线程同步：锁、Condvar 和信号量</a></li><li class="chapter-item "><a href="../advance/concurrency-with-threads/sync2.html"><strong aria-hidden="true">4.6.5.</strong> 线程同步：Atomic 原子操作与内存顺序</a></li><li class="chapter-item "><a href="../advance/concurrency-with-threads/send-sync.html"><strong aria-hidden="true">4.6.6.</strong> 基于 Send 和 Sync 的线程安全</a></li></ol></li><li class="chapter-item "><a href="../advance/global-variable.html"><strong aria-hidden="true">4.7.</strong> 全局变量</a></li><li class="chapter-item "><a href="../advance/errors.html"><strong aria-hidden="true">4.8.</strong> 错误处理</a></li><li class="chapter-item "><a href="../advance/unsafe/intro.html"><strong aria-hidden="true">4.9.</strong> Unsafe Rust</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/unsafe/superpowers.html"><strong aria-hidden="true">4.9.1.</strong> 五种兵器</a></li><li class="chapter-item "><a href="../advance/unsafe/inline-asm.html"><strong aria-hidden="true">4.9.2.</strong> 内联汇编</a></li></ol></li><li class="chapter-item expanded "><a href="../advance/macro.html" class="active"><strong aria-hidden="true">4.10.</strong> Macro 宏编程</a></li><li class="chapter-item "><a href="../advance/async/intro.html"><strong aria-hidden="true">4.11.</strong> async/await 异步编程</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance/async/getting-started.html"><strong aria-hidden="true">4.11.1.</strong> async 编程入门</a></li><li class="chapter-item "><a href="../advance/async/future-excuting.html"><strong aria-hidden="true">4.11.2.</strong> 底层探秘: Future 执行与任务调度</a></li><li class="chapter-item "><a href="../advance/async/pin-unpin.html"><strong aria-hidden="true">4.11.3.</strong> 定海神针 Pin 和 Unpin</a></li><li class="chapter-item "><a href="../advance/async/async-await.html"><strong aria-hidden="true">4.11.4.</strong> async/await 和 Stream 流处理</a></li><li class="chapter-item "><a href="../advance/async/multi-futures-simultaneous.html"><strong aria-hidden="true">4.11.5.</strong> 同时运行多个 Future</a></li><li class="chapter-item "><a href="../advance/async/pain-points-and-workarounds.html"><strong aria-hidden="true">4.11.6.</strong> 一些疑难问题的解决办法</a></li><li class="chapter-item "><a href="../advance/async/web-server.html"><strong aria-hidden="true">4.11.7.</strong> 实践应用：Async Web 服务器</a></li></ol></li></ol></li><li class="chapter-item "><a href="../advance-practice1/intro.html"><strong aria-hidden="true">5.</strong> 进阶实战1: 实现一个 web 服务器</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance-practice1/web-server.html"><strong aria-hidden="true">5.1.</strong> 单线程版本</a></li><li class="chapter-item "><a href="../advance-practice1/multi-threads.html"><strong aria-hidden="true">5.2.</strong> 多线程版本</a></li><li class="chapter-item "><a href="../advance-practice1/graceful-shutdown.html"><strong aria-hidden="true">5.3.</strong> 优雅关闭和资源清理</a></li></ol></li><li class="chapter-item "><a href="../advance-practice/intro.html"><strong aria-hidden="true">6.</strong> 进阶实战2: 实现一个简单 Redis</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../advance-practice/overview.html"><strong aria-hidden="true">6.1.</strong> tokio 概览</a></li><li class="chapter-item "><a href="../advance-practice/getting-startted.html"><strong aria-hidden="true">6.2.</strong> 使用初印象</a></li><li class="chapter-item "><a href="../advance-practice/spawning.html"><strong aria-hidden="true">6.3.</strong> 创建异步任务</a></li><li class="chapter-item "><a href="../advance-practice/shared-state.html"><strong aria-hidden="true">6.4.</strong> 共享状态</a></li><li class="chapter-item "><a href="../advance-practice/channels.html"><strong aria-hidden="true">6.5.</strong> 消息传递</a></li><li class="chapter-item "><a href="../advance-practice/io.html"><strong aria-hidden="true">6.6.</strong> I/O</a></li><li class="chapter-item "><a href="../advance-practice/frame.html"><strong aria-hidden="true">6.7.</strong> 解析数据帧</a></li><li class="chapter-item "><a href="../advance-practice/async.html"><strong aria-hidden="true">6.8.</strong> 深入 async</a></li><li class="chapter-item "><a href="../advance-practice/select.html"><strong aria-hidden="true">6.9.</strong> select</a></li><li class="chapter-item "><a href="../advance-practice/stream.html"><strong aria-hidden="true">6.10.</strong> 类似迭代器的 Stream</a></li><li class="chapter-item "><a href="../advance-practice/graceful-shutdown.html"><strong aria-hidden="true">6.11.</strong> 优雅的关闭</a></li><li class="chapter-item "><a href="../advance-practice/bridging-with-sync.html"><strong aria-hidden="true">6.12.</strong> 异步跟同步共存</a></li></ol></li><li class="chapter-item "><a href="../difficulties/intro.html"><strong aria-hidden="true">7.</strong> Rust 难点攻关</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../difficulties/slice.html"><strong aria-hidden="true">7.1.</strong> 切片和切片引用</a></li><li class="chapter-item "><a href="../difficulties/eq.html"><strong aria-hidden="true">7.2.</strong> Eq 和 PartialEq</a></li><li class="chapter-item "><a href="../difficulties/string.html"><strong aria-hidden="true">7.3.</strong> String、&str 和 str TODO</a></li><li class="chapter-item "><a href="../difficulties/lifetime.html"><strong aria-hidden="true">7.4.</strong> 作用域、生命周期和 NLL TODO</a></li><li class="chapter-item "><a href="../difficulties/move-copy.html"><strong aria-hidden="true">7.5.</strong> move、Copy 和 Clone TODO</a></li><li class="chapter-item "><a href="../advance/difficulties/pointer.html"><strong aria-hidden="true">7.6.</strong> 裸指针、引用和智能指针 TODO</a></li></ol></li><li class="chapter-item "><li class="part-title">常用工具链</li><li class="spacer"></li><li class="chapter-item "><a href="../test/intro.html"><strong aria-hidden="true">8.</strong> 自动化测试</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../test/write-tests.html"><strong aria-hidden="true">8.1.</strong> 编写测试及控制执行</a></li><li class="chapter-item "><a href="../test/unit-integration-test.html"><strong aria-hidden="true">8.2.</strong> 单元测试和集成测试</a></li><li class="chapter-item "><a href="../test/assertion.html"><strong aria-hidden="true">8.3.</strong> 断言 assertion</a></li><li class="chapter-item "><a href="../test/ci.html"><strong aria-hidden="true">8.4.</strong> 用 GitHub Actions 进行持续集成</a></li><li class="chapter-item "><a href="../test/benchmark.html"><strong aria-hidden="true">8.5.</strong> 基准测试 benchmark</a></li></ol></li><li class="chapter-item "><a href="../cargo/intro.html"><strong aria-hidden="true">9.</strong> Cargo 使用指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cargo/getting-started.html"><strong aria-hidden="true">9.1.</strong> 上手使用</a></li><li class="chapter-item "><a href="../cargo/guide/intro.html"><strong aria-hidden="true">9.2.</strong> 基础指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cargo/guide/why-exist.html"><strong aria-hidden="true">9.2.1.</strong> 为何会有 Cargo</a></li><li class="chapter-item "><a href="../cargo/guide/download-package.html"><strong aria-hidden="true">9.2.2.</strong> 下载并构建 Package</a></li><li class="chapter-item "><a href="../cargo/guide/dependencies.html"><strong aria-hidden="true">9.2.3.</strong> 添加依赖</a></li><li class="chapter-item "><a href="../cargo/guide/package-layout.html"><strong aria-hidden="true">9.2.4.</strong> Package 目录结构</a></li><li class="chapter-item "><a href="../cargo/guide/cargo-toml-lock.html"><strong aria-hidden="true">9.2.5.</strong> Cargo.toml vs Cargo.lock</a></li><li class="chapter-item "><a href="../cargo/guide/tests-ci.html"><strong aria-hidden="true">9.2.6.</strong> 测试和 CI</a></li><li class="chapter-item "><a href="../cargo/guide/cargo-cache.html"><strong aria-hidden="true">9.2.7.</strong> Cargo 缓存</a></li><li class="chapter-item "><a href="../cargo/guide/build-cache.html"><strong aria-hidden="true">9.2.8.</strong> Build 缓存</a></li></ol></li><li class="chapter-item "><a href="../cargo/reference/intro.html"><strong aria-hidden="true">9.3.</strong> 进阶指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cargo/reference/specify-deps.html"><strong aria-hidden="true">9.3.1.</strong> 指定依赖项</a></li><li class="chapter-item "><a href="../cargo/reference/deps-overriding.html"><strong aria-hidden="true">9.3.2.</strong> 依赖覆盖</a></li><li class="chapter-item "><a href="../cargo/reference/manifest.html"><strong aria-hidden="true">9.3.3.</strong> Cargo.toml 清单详解</a></li><li class="chapter-item "><a href="../cargo/reference/cargo-target.html"><strong aria-hidden="true">9.3.4.</strong> Cargo Target</a></li><li class="chapter-item "><a href="../cargo/reference/workspaces.html"><strong aria-hidden="true">9.3.5.</strong> 工作空间 Workspace</a></li><li class="chapter-item "><a href="../cargo/reference/features/intro.html"><strong aria-hidden="true">9.3.6.</strong> 条件编译 Features</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cargo/reference/features/examples.html"><strong aria-hidden="true">9.3.6.1.</strong> Features 示例</a></li></ol></li><li class="chapter-item "><a href="../cargo/reference/profiles.html"><strong aria-hidden="true">9.3.7.</strong> 发布配置 Profile</a></li><li class="chapter-item "><a href="../cargo/reference/configuration.html"><strong aria-hidden="true">9.3.8.</strong> 通过 config.toml 对 Cargo 进行配置</a></li><li class="chapter-item "><a href="../cargo/reference/publishing-on-crates.io.html"><strong aria-hidden="true">9.3.9.</strong> 发布到 crates.io</a></li><li class="chapter-item "><a href="../cargo/reference/build-script/intro.html"><strong aria-hidden="true">9.3.10.</strong> 构建脚本 build.rs</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../cargo/reference/build-script/examples.html"><strong aria-hidden="true">9.3.10.1.</strong> 构建脚本示例</a></li></ol></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">开发实践</li><li class="spacer"></li><li class="chapter-item "><a href="../usecases/intro.html"><strong aria-hidden="true">10.</strong> 企业落地实践</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../usecases/aws-rust.html"><strong aria-hidden="true">10.1.</strong> AWS 为何这么喜欢 Rust?</a></li></ol></li><li class="chapter-item "><a href="../logs/intro.html"><strong aria-hidden="true">11.</strong> 日志和监控</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../logs/about-log.html"><strong aria-hidden="true">11.1.</strong> 日志详解</a></li><li class="chapter-item "><a href="../logs/log.html"><strong aria-hidden="true">11.2.</strong> 日志门面 log</a></li><li class="chapter-item "><a href="../logs/tracing.html"><strong aria-hidden="true">11.3.</strong> 使用 tracing 记录日志</a></li><li class="chapter-item "><a href="../logs/tracing-logger.html"><strong aria-hidden="true">11.4.</strong> 自定义 tracing 的输出格式</a></li><li class="chapter-item "><a href="../logs/observe/intro.html"><strong aria-hidden="true">11.5.</strong> 监控</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../logs/observe/about-observe.html"><strong aria-hidden="true">11.5.1.</strong> 可观测性</a></li><li class="chapter-item "><a href="../logs/observe/trace.html"><strong aria-hidden="true">11.5.2.</strong> 分布式追踪</a></li></ol></li></ol></li><li class="chapter-item "><a href="../practice/intro.html"><strong aria-hidden="true">12.</strong> Rust 最佳实践</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../practice/third-party-libs.html"><strong aria-hidden="true">12.1.</strong> 日常开发三方库精选</a></li><li class="chapter-item "><a href="../practice/naming.html"><strong aria-hidden="true">12.2.</strong> 命名规范</a></li><li class="chapter-item "><a href="../practice/interview.html"><strong aria-hidden="true">12.3.</strong> 面试经验</a></li><li class="chapter-item "><a href="../practice/best-pratice.html"><strong aria-hidden="true">12.4.</strong> 代码开发实践 todo</a></li></ol></li><li class="chapter-item "><a href="../too-many-lists/intro.html"><strong aria-hidden="true">13.</strong> 手把手带你实现链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/do-we-need-it.html"><strong aria-hidden="true">13.1.</strong> 我们到底需不需要链表</a></li><li class="chapter-item "><a href="../too-many-lists/bad-stack/intro.html"><strong aria-hidden="true">13.2.</strong> 不太优秀的单向链表：栈</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/bad-stack/layout.html"><strong aria-hidden="true">13.2.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../too-many-lists/bad-stack/basic-operations.html"><strong aria-hidden="true">13.2.2.</strong> 基本操作</a></li><li class="chapter-item "><a href="../too-many-lists/bad-stack/final-code.html"><strong aria-hidden="true">13.2.3.</strong> 最后实现</a></li></ol></li><li class="chapter-item "><a href="../too-many-lists/ok-stack/intro.html"><strong aria-hidden="true">13.3.</strong> 还可以的单向链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/ok-stack/type-optimizing.html"><strong aria-hidden="true">13.3.1.</strong> 优化类型定义</a></li><li class="chapter-item "><a href="../too-many-lists/ok-stack/peek.html"><strong aria-hidden="true">13.3.2.</strong> 定义 Peek 函数</a></li><li class="chapter-item "><a href="../too-many-lists/ok-stack/iter.html"><strong aria-hidden="true">13.3.3.</strong> IntoIter 和 Iter</a></li><li class="chapter-item "><a href="../too-many-lists/ok-stack/itermut.html"><strong aria-hidden="true">13.3.4.</strong> IterMut 以及完整代码</a></li></ol></li><li class="chapter-item "><a href="../too-many-lists/persistent-stack/intro.html"><strong aria-hidden="true">13.4.</strong> 持久化单向链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/persistent-stack/layout.html"><strong aria-hidden="true">13.4.1.</strong> 数据布局和基本操作</a></li><li class="chapter-item "><a href="../too-many-lists/persistent-stack/drop-arc.html"><strong aria-hidden="true">13.4.2.</strong> Drop、Arc 及完整代码</a></li></ol></li><li class="chapter-item "><a href="../too-many-lists/deque/intro.html"><strong aria-hidden="true">13.5.</strong> 不咋样的双端队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/deque/layout.html"><strong aria-hidden="true">13.5.1.</strong> 数据布局和基本操作</a></li><li class="chapter-item "><a href="../too-many-lists/deque/peek.html"><strong aria-hidden="true">13.5.2.</strong> Peek</a></li><li class="chapter-item "><a href="../too-many-lists/deque/symmetric.html"><strong aria-hidden="true">13.5.3.</strong> 基本操作的对称镜像</a></li><li class="chapter-item "><a href="../too-many-lists/deque/iterator.html"><strong aria-hidden="true">13.5.4.</strong> 迭代器</a></li><li class="chapter-item "><a href="../too-many-lists/deque/final-code.html"><strong aria-hidden="true">13.5.5.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/intro.html"><strong aria-hidden="true">13.6.</strong> 不错的 unsafe 队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/layout.html"><strong aria-hidden="true">13.6.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/basics.html"><strong aria-hidden="true">13.6.2.</strong> 基本操作</a></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/miri.html"><strong aria-hidden="true">13.6.3.</strong> Miri</a></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/stacked-borrow.html"><strong aria-hidden="true">13.6.4.</strong> 栈借用</a></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/testing-stacked-borrow.html"><strong aria-hidden="true">13.6.5.</strong> 测试栈借用</a></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/layout2.html"><strong aria-hidden="true">13.6.6.</strong> 数据布局 2</a></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/extra-junk.html"><strong aria-hidden="true">13.6.7.</strong> 额外的操作</a></li><li class="chapter-item "><a href="../too-many-lists/unsafe-queue/final-code.html"><strong aria-hidden="true">13.6.8.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/intro.html"><strong aria-hidden="true">13.7.</strong> 生产级的双向 unsafe 队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/layout.html"><strong aria-hidden="true">13.7.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/variance-and-phantomData.html"><strong aria-hidden="true">13.7.2.</strong> 型变与子类型</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/basics.html"><strong aria-hidden="true">13.7.3.</strong> 基础结构</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/drop-and-panic-safety.html"><strong aria-hidden="true">13.7.4.</strong> 恐慌与安全</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/boring-combinatorics.html"><strong aria-hidden="true">13.7.5.</strong> 无聊的组合</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/filling-in-random-bits.html"><strong aria-hidden="true">13.7.6.</strong> 其它特征</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/testing.html"><strong aria-hidden="true">13.7.7.</strong> 测试</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/send-sync-and-compile-tests.html"><strong aria-hidden="true">13.7.8.</strong> Send,Sync和编译测试</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/implementing-cursors.html"><strong aria-hidden="true">13.7.9.</strong> 实现游标</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/testing-cursors.html"><strong aria-hidden="true">13.7.10.</strong> 测试游标</a></li><li class="chapter-item "><a href="../too-many-lists/production-unsafe-deque/final-code.html"><strong aria-hidden="true">13.7.11.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../too-many-lists/advanced-lists/intro.html"><strong aria-hidden="true">13.8.</strong> 使用高级技巧实现链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../too-many-lists/advanced-lists/double-singly.html"><strong aria-hidden="true">13.8.1.</strong> 双单向链表</a></li><li class="chapter-item "><a href="../too-many-lists/advanced-lists/stack-allocated.html"><strong aria-hidden="true">13.8.2.</strong> 栈上的链表</a></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">攻克编译错误</li><li class="spacer"></li><li class="chapter-item "><a href="../compiler/intro.html"><strong aria-hidden="true">14.</strong> 征服编译错误</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../compiler/fight-with-compiler/intro.html"><strong aria-hidden="true">14.1.</strong> 对抗编译检查</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../compiler/fight-with-compiler/lifetime/intro.html"><strong aria-hidden="true">14.1.1.</strong> 生命周期</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../compiler/fight-with-compiler/lifetime/too-long1.html"><strong aria-hidden="true">14.1.1.1.</strong> 生命周期过大-01</a></li><li class="chapter-item "><a href="../compiler/fight-with-compiler/lifetime/too-long2.html"><strong aria-hidden="true">14.1.1.2.</strong> 生命周期过大-02</a></li><li class="chapter-item "><a href="../compiler/fight-with-compiler/lifetime/loop.html"><strong aria-hidden="true">14.1.1.3.</strong> 循环中的生命周期</a></li><li class="chapter-item "><a href="../compiler/fight-with-compiler/lifetime/closure-with-static.html"><strong aria-hidden="true">14.1.1.4.</strong> 闭包碰到特征对象-01</a></li></ol></li><li class="chapter-item "><a href="../compiler/fight-with-compiler/borrowing/intro.html"><strong aria-hidden="true">14.1.2.</strong> 重复借用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../compiler/fight-with-compiler/borrowing/ref-exist-in-out-fn.html"><strong aria-hidden="true">14.1.2.1.</strong> 同时在函数内外使用引用</a></li><li class="chapter-item "><a href="../compiler/fight-with-compiler/borrowing/borrow-distinct-fields-of-struct.html"><strong aria-hidden="true">14.1.2.2.</strong> 智能指针引起的重复借用错误</a></li></ol></li><li class="chapter-item "><a href="../compiler/fight-with-compiler/unconstrained.html"><strong aria-hidden="true">14.1.3.</strong> 类型未限制(todo)</a></li><li class="chapter-item "><a href="../compiler/fight-with-compiler/phantom-data.html"><strong aria-hidden="true">14.1.4.</strong> 幽灵数据(todo)</a></li></ol></li><li class="chapter-item "><a href="../compiler/pitfalls/index.html"><strong aria-hidden="true">14.2.</strong> Rust 常见陷阱</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../compiler/pitfalls/use-vec-in-for.html"><strong aria-hidden="true">14.2.1.</strong> for 循环中使用外部数组</a></li><li class="chapter-item "><a href="../compiler/pitfalls/stack-overflow.html"><strong aria-hidden="true">14.2.2.</strong> 线程类型导致的栈溢出</a></li><li class="chapter-item "><a href="../compiler/pitfalls/arithmetic-overflow.html"><strong aria-hidden="true">14.2.3.</strong> 算术溢出导致的 panic</a></li><li class="chapter-item "><a href="../compiler/pitfalls/closure-with-lifetime.html"><strong aria-hidden="true">14.2.4.</strong> 闭包中奇怪的生命周期</a></li><li class="chapter-item "><a href="../compiler/pitfalls/the-disabled-mutability.html"><strong aria-hidden="true">14.2.5.</strong> 可变变量不可变？</a></li><li class="chapter-item "><a href="../compiler/pitfalls/multiple-mutable-references.html"><strong aria-hidden="true">14.2.6.</strong> 可变借用失败引发的深入思考</a></li><li class="chapter-item "><a href="../compiler/pitfalls/lazy-iterators.html"><strong aria-hidden="true">14.2.7.</strong> 不太勤快的迭代器</a></li><li class="chapter-item "><a href="../compiler/pitfalls/weird-ranges.html"><strong aria-hidden="true">14.2.8.</strong> 奇怪的序列 x..y</a></li><li class="chapter-item "><a href="../compiler/pitfalls/iterator-everywhere.html"><strong aria-hidden="true">14.2.9.</strong> 无处不在的迭代器</a></li><li class="chapter-item "><a href="../compiler/pitfalls/main-with-channel-blocked.html"><strong aria-hidden="true">14.2.10.</strong> 线程间传递消息导致主线程无法结束</a></li><li class="chapter-item "><a href="../compiler/pitfalls/utf8-performance.html"><strong aria-hidden="true">14.2.11.</strong> 警惕 UTF-8 引发的性能隐患</a></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">性能优化</li><li class="spacer"></li><li class="chapter-item "><a href="../profiling/intro.html"><strong aria-hidden="true">15.</strong> Rust 性能优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../profiling/memory/intro.html"><strong aria-hidden="true">15.1.</strong> 深入内存 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../profiling/memory/pointer-ref.html"><strong aria-hidden="true">15.1.1.</strong> 指针和引用 todo</a></li><li class="chapter-item "><a href="../profiling/memory/uninit.html"><strong aria-hidden="true">15.1.2.</strong> 未初始化内存 todo</a></li><li class="chapter-item "><a href="../profiling/memory/allocation.html"><strong aria-hidden="true">15.1.3.</strong> 内存分配 todo</a></li><li class="chapter-item "><a href="../profiling/memory/layout.html"><strong aria-hidden="true">15.1.4.</strong> 内存布局 todo</a></li><li class="chapter-item "><a href="../profiling/memory/virtual.html"><strong aria-hidden="true">15.1.5.</strong> 虚拟内存 todo</a></li></ol></li><li class="chapter-item "><a href="../profiling/performance/intro.html"><strong aria-hidden="true">15.2.</strong> 性能调优 doing</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../profiling/performance/string.html"><strong aria-hidden="true">15.2.1.</strong> 字符串操作性能</a></li><li class="chapter-item "><a href="../profiling/performance/deep-into-move.html"><strong aria-hidden="true">15.2.2.</strong> 深入理解 move</a></li><li class="chapter-item "><a href="../profiling/performance/early-optimise.html"><strong aria-hidden="true">15.2.3.</strong> 糟糕的提前优化 todo</a></li><li class="chapter-item "><a href="../profiling/performance/clone-copy.html"><strong aria-hidden="true">15.2.4.</strong> Clone 和 Copy todo</a></li><li class="chapter-item "><a href="../profiling/performance/runtime-check.html"><strong aria-hidden="true">15.2.5.</strong> 减少 Runtime check(todo)</a></li><li class="chapter-item "><a href="../profiling/performance/cpu-cache.html"><strong aria-hidden="true">15.2.6.</strong> CPU 缓存性能优化 todo</a></li><li class="chapter-item "><a href="../profiling/performance/calculate.html"><strong aria-hidden="true">15.2.7.</strong> 计算性能优化 todo</a></li><li class="chapter-item "><a href="../profiling/performance/heap-stack.html"><strong aria-hidden="true">15.2.8.</strong> 堆和栈 todo</a></li><li class="chapter-item "><a href="../profiling/performance/allocator.html"><strong aria-hidden="true">15.2.9.</strong> 内存 allocator todo</a></li><li class="chapter-item "><a href="../profiling/performance/tools.html"><strong aria-hidden="true">15.2.10.</strong> 常用性能测试工具 todo</a></li><li class="chapter-item "><a href="../profiling/performance/enum.html"><strong aria-hidden="true">15.2.11.</strong> Enum 内存优化 todo</a></li></ol></li><li class="chapter-item "><a href="../profiling/compiler/intro.html"><strong aria-hidden="true">15.3.</strong> 编译优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../profiling/compiler/llvm.html"><strong aria-hidden="true">15.3.1.</strong> LLVM todo</a></li><li class="chapter-item "><a href="../profiling/compiler/attributes.html"><strong aria-hidden="true">15.3.2.</strong> 常见属性标记 todo</a></li><li class="chapter-item "><a href="../profiling/compiler/speed-up.html"><strong aria-hidden="true">15.3.3.</strong> 提升编译速度 todo</a></li><li class="chapter-item "><a href="../profiling/compiler/optimization/intro.html"><strong aria-hidden="true">15.3.4.</strong> 编译器优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../profiling/compiler/optimization/option.html"><strong aria-hidden="true">15.3.4.1.</strong> Option 枚举 todo</a></li></ol></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">附录</li><li class="spacer"></li><li class="chapter-item "><div><strong aria-hidden="true">16.</strong> Appendix</div><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../appendix/keywords.html"><strong aria-hidden="true">16.1.</strong> 关键字</a></li><li class="chapter-item "><a href="../appendix/operators.html"><strong aria-hidden="true">16.2.</strong> 运算符与符号</a></li><li class="chapter-item "><a href="../appendix/expressions.html"><strong aria-hidden="true">16.3.</strong> 表达式</a></li><li class="chapter-item "><a href="../appendix/derive.html"><strong aria-hidden="true">16.4.</strong> 派生特征 trait</a></li><li class="chapter-item "><a href="../appendix/prelude.html"><strong aria-hidden="true">16.5.</strong> prelude 模块 todo</a></li><li class="chapter-item "><a href="../appendix/rust-version.html"><strong aria-hidden="true">16.6.</strong> Rust 版本说明</a></li><li class="chapter-item "><a href="../appendix/rust-versions/intro.html"><strong aria-hidden="true">16.7.</strong> Rust 历次版本更新解读</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../appendix/rust-versions/1.58.html"><strong aria-hidden="true">16.7.1.</strong> 1.58</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.59.html"><strong aria-hidden="true">16.7.2.</strong> 1.59</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.60.html"><strong aria-hidden="true">16.7.3.</strong> 1.60</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.61.html"><strong aria-hidden="true">16.7.4.</strong> 1.61</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.62.html"><strong aria-hidden="true">16.7.5.</strong> 1.62</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.63.html"><strong aria-hidden="true">16.7.6.</strong> 1.63</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.64.html"><strong aria-hidden="true">16.7.7.</strong> 1.64</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.65.html"><strong aria-hidden="true">16.7.8.</strong> 1.65</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.66.html"><strong aria-hidden="true">16.7.9.</strong> 1.66</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.67.html"><strong aria-hidden="true">16.7.10.</strong> 1.67</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.68.html"><strong aria-hidden="true">16.7.11.</strong> 1.68</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.69.html"><strong aria-hidden="true">16.7.12.</strong> 1.69</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.70.html"><strong aria-hidden="true">16.7.13.</strong> 1.70</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.71.html"><strong aria-hidden="true">16.7.14.</strong> 1.71</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.72.html"><strong aria-hidden="true">16.7.15.</strong> 1.72</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.73.html"><strong aria-hidden="true">16.7.16.</strong> 1.73</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.74.html"><strong aria-hidden="true">16.7.17.</strong> 1.74</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.75.html"><strong aria-hidden="true">16.7.18.</strong> 1.75</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.76.html"><strong aria-hidden="true">16.7.19.</strong> 1.76</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.77.html"><strong aria-hidden="true">16.7.20.</strong> 1.77</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.78.html"><strong aria-hidden="true">16.7.21.</strong> 1.78</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.79.html"><strong aria-hidden="true">16.7.22.</strong> 1.79</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.80.html"><strong aria-hidden="true">16.7.23.</strong> 1.80</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.81.html"><strong aria-hidden="true">16.7.24.</strong> 1.81</a></li><li class="chapter-item "><a href="../appendix/rust-versions/1.82.html"><strong aria-hidden="true">16.7.25.</strong> 1.82</a></li></ol></li></ol></li></ol>
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<h1 id="macro-宏编程"><a class="header" href="#macro-宏编程">Macro 宏编程</a></h1>
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<p>在编程世界可以说是谈“宏”色变，原因在于 C 语言中的宏是非常危险的东东，但并不是所有语言都像 C 这样，例如对于古老的语言 Lisp 来说，宏就是就是一个非常强大的好帮手。</p>
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<p>那话说回来，在 Rust 中宏到底是好是坏呢？本章将带你揭开它的神秘面纱。</p>
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<p>事实上，我们虽然没有见过宏，但是已经多次用过它，例如在全书的第一个例子中就用到了：<code>println!("你好，世界")</code>，这里 <code>println!</code> 就是一个最常用的宏，可以看到它和函数最大的区别是：它在调用时多了一个 <code>!</code>，除此之外还有 <code>vec!</code> 、<code>assert_eq!</code> 都是相当常用的，可以说<strong>宏在 Rust 中无处不在</strong>。</p>
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<p>细心的读者可能会注意到 <code>println!</code> 后面跟着的是 <code>()</code>，而 <code>vec!</code> 后面跟着的是 <code>[]</code>，这是因为宏的参数可以使用 <code>()</code>、<code>[]</code> 以及 <code>{}</code>:</p>
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<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
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println!("aaaa");
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println!["aaaa"];
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println!{"aaaa"}
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}</code></pre></pre>
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<p>虽然三种使用形式皆可，但是 Rust 内置的宏都有自己约定俗成的使用方式，例如 <code>vec![...]</code>、<code>assert_eq!(...)</code> 等。</p>
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<p>在 Rust 中宏分为两大类：<strong>声明式宏( <em>declarative macros</em> )</strong> <code>macro_rules!</code> 和三种<strong>过程宏( <em>procedural macros</em> )</strong>:</p>
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<ul>
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<li><code>#[derive]</code>，在之前多次见到的派生宏，可以为目标结构体或枚举派生指定的代码，例如 <code>Debug</code> 特征</li>
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<li>类属性宏(Attribute-like macro)，用于为目标添加自定义的属性</li>
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<li>类函数宏(Function-like macro)，看上去就像是函数调用</li>
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</ul>
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<p>如果感觉难以理解，也不必担心，接下来我们将逐个看看它们的庐山真面目，在此之前，先来看下为何需要宏，特别是 Rust 的函数明明已经很强大了。</p>
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<h2 id="宏和函数的区别"><a class="header" href="#宏和函数的区别">宏和函数的区别</a></h2>
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<p>宏和函数的区别并不少，而且对于宏擅长的领域，函数其实是有些无能为力的。</p>
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<h4 id="元编程"><a class="header" href="#元编程">元编程</a></h4>
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<p>从根本上来说，宏是通过一种代码来生成另一种代码，如果大家熟悉元编程，就会发现两者的共同点。</p>
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<p>在<a href="https://course.rs/appendix/derive.html">附录 D</a>中讲到的 <code>derive</code> 属性，就会自动为结构体派生出相应特征所需的代码，例如 <code>#[derive(Debug)]</code>，还有熟悉的 <code>println!</code> 和 <code>vec!</code>，所有的这些宏都会展开成相应的代码，且很可能是长得多的代码。</p>
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<p>总之，元编程可以帮我们减少所需编写的代码，也可以一定程度上减少维护的成本，虽然函数复用也有类似的作用，但是宏依然拥有自己独特的优势。</p>
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<h4 id="可变参数"><a class="header" href="#可变参数">可变参数</a></h4>
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<p>Rust 的函数签名是固定的：定义了两个参数，就必须传入两个参数，多一个少一个都不行，对于从 JS/TS 过来的同学，这一点其实是有些恼人的。</p>
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<p>而宏就可以拥有可变数量的参数，例如可以调用一个参数的 <code>println!("hello")</code>，也可以调用两个参数的 <code>println!("hello {}", name)</code>。</p>
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<h4 id="宏展开"><a class="header" href="#宏展开">宏展开</a></h4>
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|
|
<p>由于宏会被展开成其它代码，且这个展开过程是发生在编译器对代码进行解释之前。因此，宏可以为指定的类型实现某个特征：先将宏展开成实现特征的代码后，再被编译。</p>
|
|
|
<p>而函数就做不到这一点，因为它直到运行时才能被调用，而特征需要在编译期被实现。</p>
|
|
|
<h4 id="宏的缺点"><a class="header" href="#宏的缺点">宏的缺点</a></h4>
|
|
|
<p>相对函数来说，由于宏是基于代码再展开成代码，因此实现相比函数来说会更加复杂，再加上宏的语法更为复杂，最终导致定义宏的代码相当地难读，也难以理解和维护。</p>
|
|
|
<h2 id="声明式宏-macro_rules"><a class="header" href="#声明式宏-macro_rules">声明式宏 <code>macro_rules!</code></a></h2>
|
|
|
<p>在 Rust 中使用最广的就是声明式宏，它们也有一些其它的称呼，例如示例宏( macros by example )、<code>macro_rules!</code> 或干脆直接称呼为<strong>宏</strong>。</p>
|
|
|
<p>声明式宏允许我们写出类似 <code>match</code> 的代码。<code>match</code> 表达式是一个控制结构，其接收一个表达式，然后将表达式的结果与多个模式进行匹配，一旦匹配了某个模式，则该模式相关联的代码将被执行:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>match target {
|
|
|
模式1 => 表达式1,
|
|
|
模式2 => {
|
|
|
语句1;
|
|
|
语句2;
|
|
|
表达式2
|
|
|
},
|
|
|
_ => 表达式3
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>而<strong>宏也是将一个值跟对应的模式进行匹配，且该模式会与特定的代码相关联</strong>。但是与 <code>match</code> 不同的是，<strong>宏里的值是一段 Rust 源代码</strong>(字面量)，模式用于跟这段源代码的结构相比较，一旦匹配，传入宏的那段源代码将被模式关联的代码所替换，最终实现宏展开。值得注意的是，<strong>所有的这些都是在编译期发生，并没有运行期的性能损耗</strong>。</p>
|
|
|
<h4 id="简化版的-vec"><a class="header" href="#简化版的-vec">简化版的 vec!</a></h4>
|
|
|
<p>在<a href="https://course.rs/basic/collections/vector.html#vec">动态数组 Vector 章节</a>中，我们学习了使用 <code>vec!</code> 来便捷的初始化一个动态数组:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>let v: Vec<u32> = vec![1, 2, 3];
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>最重要的是，通过 <code>vec!</code> 创建的动态数组支持任何元素类型，也并没有限制数组的长度，如果使用函数，我们是无法做到这一点的。</p>
|
|
|
<p>好在我们有 <code>macro_rules!</code>，来看看该如何使用它来实现 <code>vec!</code>，以下是一个简化实现：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>#[macro_export]
|
|
|
macro_rules! vec {
|
|
|
( $( $x:expr ),* ) => {
|
|
|
{
|
|
|
let mut temp_vec = Vec::new();
|
|
|
$(
|
|
|
temp_vec.push($x);
|
|
|
)*
|
|
|
temp_vec
|
|
|
}
|
|
|
};
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>简化实现版本？这也太难了吧！！只能说，欢迎来到宏的世界，在这里你能见到优雅 Rust 的另一面:) 标准库中的 <code>vec!</code> 还包含了预分配内存空间的代码，如果引入进来，那大家将更难以接受。</p>
|
|
|
<p><code>#[macro_export]</code> 注释将宏进行了导出，这样其它的包就可以将该宏引入到当前作用域中，然后才能使用。可能有同学会提问：我们在使用标准库 <code>vec!</code> 时也没有引入宏啊，那是因为 Rust 已经通过 <a href="https://course.rs/appendix/prelude.html"><code>std::prelude</code></a> 的方式为我们自动引入了。</p>
|
|
|
<p>紧接着，就使用 <code>macro_rules!</code> 进行了宏定义，需要注意的是宏的名称是 <code>vec</code>，而不是 <code>vec!</code>，后者的感叹号只在调用时才需要。</p>
|
|
|
<p><code>vec</code> 的定义结构跟 <code>match</code> 表达式很像，但这里我们只有一个分支，其中包含一个模式 <code>( $( $x:expr ),* )</code>，跟模式相关联的代码就在 <code>=></code> 之后。一旦模式成功匹配，那这段相关联的代码就会替换传入的源代码。</p>
|
|
|
<p>由于 <code>vec</code> 宏只有一个模式，因此它只能匹配一种源代码，其它类型的都将导致报错，而更复杂的宏往往会拥有更多的分支。</p>
|
|
|
<p>虽然宏和 <code>match</code> 都称之为模式，但是前者跟<a href="https://course.rs/basic/match-pattern/all-patterns.html">后者</a>的模式规则是不同的。如果大家想要更深入的了解宏的模式，可以查看<a href="https://doc.rust-lang.org/reference/macros-by-example.html">这里</a>。</p>
|
|
|
<h4 id="模式解析"><a class="header" href="#模式解析">模式解析</a></h4>
|
|
|
<p>而现在，我们先来简单讲解下 <code>( $( $x:expr ),* )</code> 的含义。</p>
|
|
|
<p>首先，我们使用圆括号 <code>()</code> 将整个宏模式包裹其中。紧随其后的是 <code>$()</code>，跟括号中模式相匹配的值(传入的 Rust 源代码)会被捕获，然后用于代码替换。在这里，模式 <code>$x:expr</code> 会匹配任何 Rust 表达式并给予该模式一个名称：<code>$x</code>。</p>
|
|
|
<p><code>$()</code> 之后的逗号说明在 <code>$()</code> 所匹配的代码的后面会有一个可选的逗号分隔符，紧随逗号之后的 <code>*</code> 说明 <code>*</code> 之前的模式会被匹配零次或任意多次(类似正则表达式)。</p>
|
|
|
<p>当我们使用 <code>vec![1, 2, 3]</code> 来调用该宏时，<code>$x</code> 模式将被匹配三次，分别是 <code>1</code>、<code>2</code>、<code>3</code>。为了帮助大家巩固，我们再来一起过一下：</p>
|
|
|
<ol>
|
|
|
<li><code>$()</code> 中包含的是模式 <code>$x:expr</code>，该模式中的 <code>expr</code> 表示会匹配任何 Rust 表达式，并给予该模式一个名称 <code>$x</code></li>
|
|
|
<li>因此 <code>$x</code> 模式可以跟整数 <code>1</code> 进行匹配，也可以跟字符串 "hello" 进行匹配: <code>vec!["hello", "world"]</code></li>
|
|
|
<li><code>$()</code> 之后的逗号，意味着<code>1</code> 和 <code>2</code> 之间可以使用逗号进行分割，也意味着 <code>3</code> 既可以没有逗号，也可以有逗号：<code>vec![1, 2, 3,]</code></li>
|
|
|
<li><code>*</code> 说明之前的模式可以出现零次也可以任意次，这里出现了三次</li>
|
|
|
</ol>
|
|
|
<p>接下来，我们再来看看与模式相关联、在 <code>=></code> 之后的代码：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>{
|
|
|
{
|
|
|
let mut temp_vec = Vec::new();
|
|
|
$(
|
|
|
temp_vec.push($x);
|
|
|
)*
|
|
|
temp_vec
|
|
|
}
|
|
|
};
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>这里就比较好理解了，<code>$()</code> 中的 <code>temp_vec.push()</code> 将根据模式匹配的次数生成对应的代码，当调用 <code>vec![1, 2, 3]</code> 时，下面这段生成的代码将替代传入的源代码，也就是替代 <code>vec![1, 2, 3]</code> :</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>{
|
|
|
let mut temp_vec = Vec::new();
|
|
|
temp_vec.push(1);
|
|
|
temp_vec.push(2);
|
|
|
temp_vec.push(3);
|
|
|
temp_vec
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>如果是 <code>let v = vec![1, 2, 3]</code>，那生成的代码最后返回的值 <code>temp_vec</code> 将被赋予给变量 <code>v</code>，等同于 :</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>let v = {
|
|
|
let mut temp_vec = Vec::new();
|
|
|
temp_vec.push(1);
|
|
|
temp_vec.push(2);
|
|
|
temp_vec.push(3);
|
|
|
temp_vec
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>至此，我们定义了一个宏，它可以接受任意类型和数量的参数，并且理解了其语法的含义。</p>
|
|
|
<h4 id="未来将被替代的-macro_rules"><a class="header" href="#未来将被替代的-macro_rules">未来将被替代的 <code>macro_rules</code></a></h4>
|
|
|
<p>对于 <code>macro_rules</code> 来说，它是存在一些问题的，因此，Rust 计划在未来使用新的声明式宏来替换它：工作方式类似，但是解决了目前存在的一些问题，在那之后，<code>macro_rules</code> 将变为 <code>deprecated</code> 状态。</p>
|
|
|
<p>由于绝大多数 Rust 开发者都是宏的用户而不是编写者，因此在这里我们不会对 <code>macro_rules</code> 进行更深入的学习，如果大家感兴趣，可以看看这本书 <a href="https://veykril.github.io/tlborm/"> “The Little Book of Rust Macros”</a>。</p>
|
|
|
<h2 id="用过程宏为属性标记生成代码"><a class="header" href="#用过程宏为属性标记生成代码">用过程宏为属性标记生成代码</a></h2>
|
|
|
<p>第二种常用的宏就是<a href="https://doc.rust-lang.org/reference/procedural-macros.html"><em>过程宏</em></a> ( <em>procedural macros</em> )，从形式上来看，过程宏跟函数较为相像，但过程宏是使用源代码作为输入参数，基于代码进行一系列操作后，再输出一段全新的代码。<strong>注意，过程宏中的 derive 宏输出的代码并不会替换之前的代码，这一点与声明宏有很大的不同！</strong></p>
|
|
|
<p>至于前文提到的过程宏的三种类型(自定义 <code>derive</code>、属性宏、函数宏)，它们的工作方式都是类似的。</p>
|
|
|
<p>当<strong>创建过程宏</strong>时，它的定义必须要放入一个独立的包中，且包的类型也是特殊的，这么做的原因相当复杂，大家只要知道这种限制在未来可能会有所改变即可。</p>
|
|
|
<blockquote>
|
|
|
<p>事实上，根据<a href="https://www.reddit.com/r/rust/comments/t1oa1e/what_are_the_complex_technical_reasons_why/">这个说法</a>，过程宏放入独立包的原因在于它必须先被编译后才能使用，如果过程宏和使用它的代码在一个包，就必须先单独对过程宏的代码进行编译，然后再对我们的代码进行编译，但悲剧的是 Rust 的编译单元是包，因此你无法做到这一点。</p>
|
|
|
</blockquote>
|
|
|
<p>假设我们要创建一个 <code>derive</code> 类型的过程宏：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>use proc_macro;
|
|
|
|
|
|
#[proc_macro_derive(HelloMacro)]
|
|
|
pub fn some_name(input: TokenStream) -> TokenStream {
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>用于定义过程宏的函数 <code>some_name</code> 使用 <code>TokenStream</code> 作为输入参数，并且返回的也是同一个类型。<code>TokenStream</code> 是在 <code>proc_macro</code> 包中定义的，顾名思义，它代表了一个 <code>Token</code> 序列。</p>
|
|
|
<p>在理解了过程宏的基本定义后，我们再来看看该如何创建三种类型的过程宏，首先，从大家最熟悉的 <code>derive</code> 开始。</p>
|
|
|
<h2 id="自定义-derive-过程宏"><a class="header" href="#自定义-derive-过程宏">自定义 <code>derive</code> 过程宏</a></h2>
|
|
|
<p>假设我们有一个特征 <code>HelloMacro</code>，现在有两种方式让用户使用它：</p>
|
|
|
<ul>
|
|
|
<li>为每个类型手动实现该特征，就像之前<a href="https://course.rs/basic/trait/trait.html#%E4%B8%BA%E7%B1%BB%E5%9E%8B%E5%AE%9E%E7%8E%B0%E7%89%B9%E5%BE%81">特征章节</a>所做的</li>
|
|
|
<li>使用过程宏来统一实现该特征，这样用户只需要对类型进行标记即可：<code>#[derive(HelloMacro)]</code></li>
|
|
|
</ul>
|
|
|
<p>以上两种方式并没有孰优孰劣，主要在于不同的类型是否可以使用同样的默认特征实现，如果可以，那过程宏的方式可以帮我们减少很多代码实现:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">use hello_macro::HelloMacro;
|
|
|
use hello_macro_derive::HelloMacro;
|
|
|
|
|
|
#[derive(HelloMacro)]
|
|
|
struct Sunfei;
|
|
|
|
|
|
#[derive(HelloMacro)]
|
|
|
struct Sunface;
|
|
|
|
|
|
fn main() {
|
|
|
Sunfei::hello_macro();
|
|
|
Sunface::hello_macro();
|
|
|
}</code></pre></pre>
|
|
|
<p>简单吗？简单！不过为了实现这段代码展示的功能，我们还需要创建相应的过程宏才行。 首先，创建一个新的工程用于演示：</p>
|
|
|
<pre><code class="language-shell">$ cargo new hello_macro
|
|
|
$ cd hello_macro/
|
|
|
$ touch src/lib.rs
|
|
|
</code></pre>
|
|
|
<p>此时，<code>src</code> 目录下包含两个文件 <code>lib.rs</code> 和 <code>main.rs</code>，前者是 <code>lib</code> 包根，后者是二进制包根，如果大家对包根不熟悉，可以看看<a href="https://course.rs/basic/crate-module/crate.html">这里</a>。</p>
|
|
|
<p>接下来，先在 <code>src/lib.rs</code> 中定义过程宏所需的 <code>HelloMacro</code> 特征和其关联函数:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>pub trait HelloMacro {
|
|
|
fn hello_macro();
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>然后在 <code>src/main.rs</code> 中编写主体代码，首先映入大家脑海的可能会是如下实现:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">use hello_macro::HelloMacro;
|
|
|
|
|
|
struct Sunfei;
|
|
|
|
|
|
impl HelloMacro for Sunfei {
|
|
|
fn hello_macro() {
|
|
|
println!("Hello, Macro! My name is Sunfei!");
|
|
|
}
|
|
|
}
|
|
|
|
|
|
struct Sunface;
|
|
|
|
|
|
impl HelloMacro for Sunface {
|
|
|
fn hello_macro() {
|
|
|
println!("Hello, Macro! My name is Sunface!");
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn main() {
|
|
|
Sunfei::hello_macro();
|
|
|
}</code></pre></pre>
|
|
|
<p>但是这种方式有个问题，如果想要实现不同的招呼内容，就需要为每一个类型都实现一次相应的特征，Rust 不支持反射，因此我们无法在运行时获得类型名。</p>
|
|
|
<p>使用宏，就不存在这个问题：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">use hello_macro::HelloMacro;
|
|
|
use hello_macro_derive::HelloMacro;
|
|
|
|
|
|
#[derive(HelloMacro)]
|
|
|
struct Sunfei;
|
|
|
|
|
|
#[derive(HelloMacro)]
|
|
|
struct Sunface;
|
|
|
|
|
|
fn main() {
|
|
|
Sunfei::hello_macro();
|
|
|
Sunface::hello_macro();
|
|
|
}</code></pre></pre>
|
|
|
<p>简单明了的代码总是令人愉快，为了让代码运行起来，还需要定义下过程宏。就如前文提到的，目前只能在单独的包中定义过程宏，尽管未来这种限制会被取消，但是现在我们还得遵循这个规则。</p>
|
|
|
<p>宏所在的包名自然也有要求，必须以 <code>derive</code> 为后缀，对于 <code>hello_macro</code> 宏而言，包名就应该是 <code>hello_macro_derive</code>。在之前创建的 <code>hello_macro</code> 项目根目录下，运行如下命令，创建一个单独的 <code>lib</code> 包:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>cargo new hello_macro_derive --lib
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>至此， <code>hello_macro</code> 项目的目录结构如下：</p>
|
|
|
<pre><code class="language-shell">hello_macro
|
|
|
├── Cargo.toml
|
|
|
├── src
|
|
|
│ ├── main.rs
|
|
|
│ └── lib.rs
|
|
|
└── hello_macro_derive
|
|
|
├── Cargo.toml
|
|
|
├── src
|
|
|
└── lib.rs
|
|
|
</code></pre>
|
|
|
<p>由于过程宏所在的包跟我们的项目紧密相连，因此将它放在项目之中。现在，问题又来了，该如何在项目的 <code>src/main.rs</code> 中引用 <code>hello_macro_derive</code> 包的内容？</p>
|
|
|
<p>方法有两种，第一种是将 <code>hello_macro_derive</code> 发布到 <code>crates.io</code> 或 <code>GitHub</code> 中，就像我们引用的其它依赖一样；另一种就是使用相对路径引入的本地化方式，修改 <code>hello_macro/Cargo.toml</code> 文件添加以下内容:</p>
|
|
|
<pre><code class="language-toml">[dependencies]
|
|
|
hello_macro_derive = { path = "../hello_macro/hello_macro_derive" }
|
|
|
# 也可以使用下面的相对路径
|
|
|
# hello_macro_derive = { path = "./hello_macro_derive" }
|
|
|
</code></pre>
|
|
|
<p>此时，<code>hello_macro</code> 项目就可以成功的引用到 <code>hello_macro_derive</code> 本地包了，对于项目依赖引入的详细介绍，可以参见 <a href="https://course.rs/cargo/dependency.html">Cargo 章节</a>。</p>
|
|
|
<p>另外，学习过程更好的办法是通过展开宏来阅读和调试自己写的宏，这里需要用到一个 cargo-expand 的工具，可以通过下面的命令安装</p>
|
|
|
<pre><code class="language-bash">cargo install cargo-expand
|
|
|
</code></pre>
|
|
|
<p>接下来，就到了重头戏环节，一起来看看该如何定义过程宏。</p>
|
|
|
<h4 id="定义过程宏"><a class="header" href="#定义过程宏">定义过程宏</a></h4>
|
|
|
<p>首先，在 <code>hello_macro_derive/Cargo.toml</code> 文件中添加以下内容：</p>
|
|
|
<pre><code class="language-toml">[lib]
|
|
|
proc-macro = true
|
|
|
|
|
|
[dependencies]
|
|
|
syn = "1.0"
|
|
|
quote = "1.0"
|
|
|
</code></pre>
|
|
|
<p>其中 <code>syn</code> 和 <code>quote</code> 依赖包都是定义过程宏所必需的，同时，还需要在 <code>[lib]</code> 中将过程宏的开关开启 : <code>proc-macro = true</code>。</p>
|
|
|
<p>其次，在 <code>hello_macro_derive/src/lib.rs</code> 中添加如下代码：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>extern crate proc_macro;
|
|
|
|
|
|
use proc_macro::TokenStream;
|
|
|
use quote::quote;
|
|
|
use syn;
|
|
|
use syn::DeriveInput;
|
|
|
|
|
|
#[proc_macro_derive(HelloMacro)]
|
|
|
pub fn hello_macro_derive(input: TokenStream) -> TokenStream {
|
|
|
// 基于 input 构建 AST 语法树
|
|
|
let ast:DeriveInput = syn::parse(input).unwrap();
|
|
|
|
|
|
// 构建特征实现代码
|
|
|
impl_hello_macro(&ast)
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>这个函数的签名我们在之前已经介绍过，总之，这种形式的过程宏定义是相当通用的，下面来分析下这段代码。</p>
|
|
|
<p>首先有一点，对于绝大多数过程宏而言，这段代码往往只在 <code>impl_hello_macro(&ast)</code> 中的实现有所区别，对于其它部分基本都是一致的，如包的引入、宏函数的签名、语法树构建等。</p>
|
|
|
<p><code>proc_macro</code> 包是 Rust 自带的，因此无需在 <code>Cargo.toml</code> 中引入依赖，它包含了相关的编译器 <code>API</code>，可以用于读取和操作 Rust 源代码。</p>
|
|
|
<p>由于我们为 <code>hello_macro_derive</code> 函数标记了 <code>#[proc_macro_derive(HelloMacro)]</code>，当用户使用 <code>#[derive(HelloMacro)]</code> 标记了他的类型后，<code>hello_macro_derive</code> 函数就将被调用。这里的秘诀就是特征名 <code>HelloMacro</code>，它就像一座桥梁，将用户的类型和过程宏联系在一起。</p>
|
|
|
<p><code>syn</code> 将字符串形式的 Rust 代码解析为一个 AST 树的数据结构，该数据结构可以在随后的 <code>impl_hello_macro</code> 函数中进行操作。最后，操作的结果又会被 <code>quote</code> 包转换回 Rust 代码。这些包非常关键，可以帮我们节省大量的精力，否则你需要自己去编写支持代码解析和还原的解析器，这可不是一件简单的任务！</p>
|
|
|
<p>derive过程宏只能用在struct/enum/union上，多数用在结构体上，我们先来看一下一个结构体由哪些部分组成:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>// vis，可视范围 ident，标识符 generic，范型 fields: 结构体的字段
|
|
|
pub struct User <'a, T> {
|
|
|
|
|
|
// vis ident type
|
|
|
pub name: &'a T,
|
|
|
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>其中type还可以细分，具体请阅读syn文档或源码</p>
|
|
|
<p><code>syn::parse</code> 调用会返回一个 <code>DeriveInput</code> 结构体来代表解析后的 Rust 代码:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>DeriveInput {
|
|
|
// --snip--
|
|
|
vis: Visibility,
|
|
|
ident: Ident {
|
|
|
ident: "Sunfei",
|
|
|
span: #0 bytes(95..103)
|
|
|
},
|
|
|
generics: Generics,
|
|
|
// Data是一个枚举，分别是DataStruct，DataEnum，DataUnion，这里以 DataStruct 为例
|
|
|
data: Data(
|
|
|
DataStruct {
|
|
|
struct_token: Struct,
|
|
|
fields: Fields,
|
|
|
semi_token: Some(
|
|
|
Semi
|
|
|
)
|
|
|
}
|
|
|
)
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>以上就是源代码 <code>struct Sunfei;</code> 解析后的结果，里面有几点值得注意:</p>
|
|
|
<ul>
|
|
|
<li><code>fields: Fields</code> 是一个枚举类型，<code>Fields::Named</code>, <code>Fields::Unnamed</code>, <code>Fields::Unit</code> 分别表示结构体中的显式命名字段（如例子所示），元组或元组变体中的匿名字段(例如<code>Some(T)</code>)，单元类型或单元变体字段（例如<code>None</code> ）。</li>
|
|
|
<li><code>ident: "Sunfei"</code> 说明类型名称为 <code>Sunfei</code>， <code>ident</code> 是标识符 <code>identifier</code> 的简写</li>
|
|
|
</ul>
|
|
|
<p>如果想要了解更多的信息，可以查看 <a href="https://docs.rs/syn/1.0/syn/struct.DeriveInput.html"><code>syn</code> 文档</a>。</p>
|
|
|
<p>大家可能会注意到在 <code>hello_macro_derive</code> 函数中有 <code>unwrap</code> 的调用，也许会以为这是为了演示目的，没有做错误处理，实际上并不是的。由于该函数只能返回 <code>TokenStream</code> 而不是 <code>Result</code>，那么在报错时直接 <code>panic</code> 来抛出错误就成了相当好的选择。当然，这里实际上还是做了简化，在生产项目中，你应该通过 <code>panic!</code> 或 <code>expect</code> 抛出更具体的报错信息。</p>
|
|
|
<p>至此，这个函数大家应该已经基本理解了，下面来看看如何构建特征实现的代码，也是过程宏的核心目标:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>fn impl_hello_macro(ast: &syn::DeriveInput) -> TokenStream {
|
|
|
let name = &ast.ident;
|
|
|
let gen = quote! {
|
|
|
impl HelloMacro for #name {
|
|
|
fn hello_macro() {
|
|
|
println!("Hello, Macro! My name is {}!", stringify!(#name));
|
|
|
}
|
|
|
}
|
|
|
};
|
|
|
gen.into()
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>首先，将结构体的名称赋予给 <code>name</code>，也就是 <code>name</code> 中会包含一个字段，它的值是字符串 "Sunfei"。</p>
|
|
|
<p>其次，使用 <code>quote!</code> 可以定义我们想要返回的 Rust 代码。由于编译器需要的内容和 <code>quote!</code> 直接返回的不一样，因此还需要使用 <code>.into</code> 方法其转换为 <code>TokenStream</code>。</p>
|
|
|
<p>大家注意到 <code>#name</code> 的使用了吗？这也是 <code>quote!</code> 提供的功能之一，如果想要深入了解 <code>quote</code>，可以看看<a href="https://docs.rs/quote">官方文档</a>。</p>
|
|
|
<p>特征的 <code>hell_macro()</code> 函数只有一个功能，就是使用 <code>println!</code> 打印一行欢迎语句。</p>
|
|
|
<p>其中 <code>stringify!</code> 是 Rust 提供的内置宏，可以将一个表达式(例如 <code>1 + 2</code>)在编译期转换成一个字符串字面值(<code>"1 + 2"</code>)，该字面量会直接打包进编译出的二进制文件中，具有 <code>'static</code> 生命周期。而 <code>format!</code> 宏会对表达式进行求值，最终结果是一个 <code>String</code> 类型。在这里使用 <code>stringify!</code> 有两个好处:</p>
|
|
|
<ul>
|
|
|
<li><code>#name</code> 可能是一个表达式，我们需要它的字面值形式</li>
|
|
|
<li>可以减少一次 <code>String</code> 带来的内存分配</li>
|
|
|
</ul>
|
|
|
<p>在运行之前，可以先用 expand 展开宏，观察是否有错误或符合预期:</p>
|
|
|
<pre><code class="language-shell">$ cargo expand --bin hello_macro
|
|
|
</code></pre>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">struct Sunfei;
|
|
|
impl HelloMacro for Sunfei {
|
|
|
fn hello_macro() {
|
|
|
{
|
|
|
::std::io::_print(
|
|
|
::core::fmt::Arguments::new_v1(
|
|
|
&["Hello, Macro! My name is ", "!\n"],
|
|
|
&[::core::fmt::ArgumentV1::new_display(&"Sunfei")],
|
|
|
),
|
|
|
);
|
|
|
};
|
|
|
}
|
|
|
}
|
|
|
struct Sunface;
|
|
|
impl HelloMacro for Sunface {
|
|
|
fn hello_macro() {
|
|
|
{
|
|
|
::std::io::_print(
|
|
|
::core::fmt::Arguments::new_v1(
|
|
|
&["Hello, Macro! My name is ", "!\n"],
|
|
|
&[::core::fmt::ArgumentV1::new_display(&"Sunface")],
|
|
|
),
|
|
|
);
|
|
|
};
|
|
|
}
|
|
|
}
|
|
|
fn main() {
|
|
|
Sunfei::hello_macro();
|
|
|
Sunface::hello_macro();
|
|
|
}</code></pre></pre>
|
|
|
<p>从展开的代码也能看出derive宏的特性，<code>struct Sunfei;</code> 和 <code>struct Sunface;</code> 都被保留了，也就是说最后 <code>impl_hello_macro()</code> 返回的token被加到结构体后面，这和类属性宏可以修改输入
|
|
|
的token是不一样的，input的token并不能被修改。</p>
|
|
|
<p>至此，过程宏的定义、特征定义、主体代码都已经完成，运行下试试:</p>
|
|
|
<pre><code class="language-shell">$ cargo run
|
|
|
|
|
|
Running `target/debug/hello_macro`
|
|
|
Hello, Macro! My name is Sunfei!
|
|
|
Hello, Macro! My name is Sunface!
|
|
|
</code></pre>
|
|
|
<p>Bingo，虽然过程有些复杂，但是结果还是很喜人，我们终于完成了自己的第一个过程宏！</p>
|
|
|
<p>下面来实现一个更实用的例子，实现官方的#[derive(Default)]宏，废话不说直接开干:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>extern crate proc_macro;
|
|
|
use proc_macro::TokenStream;
|
|
|
use quote::quote;
|
|
|
use syn::{self, Data};
|
|
|
use syn::DeriveInput;
|
|
|
|
|
|
#[proc_macro_derive(MyDefault)]
|
|
|
pub fn my_default(input: TokenStream) -> TokenStream {
|
|
|
let ast: DeriveInput = syn::parse(input).unwrap();
|
|
|
let id = ast.ident;
|
|
|
|
|
|
let Data::Struct(s) = ast.data else{
|
|
|
panic!("MyDefault derive macro must use in struct");
|
|
|
};
|
|
|
|
|
|
// 声明一个新的ast，用于动态构建字段赋值的token
|
|
|
let mut field_ast = quote!();
|
|
|
|
|
|
// 这里就是要动态添加token的地方了，需要动态完成Self的字段赋值
|
|
|
for (idx,f) in s.fields.iter().enumerate() {
|
|
|
let (field_id, field_ty) = (&f.ident, &f.ty);
|
|
|
|
|
|
|
|
|
if field_id.is_none(){
|
|
|
//没有ident表示是匿名字段，对于匿名字段，都需要添加 `#field_idx: #field_type::default(),` 这样的代码
|
|
|
let field_idx = syn::Index::from(idx);
|
|
|
field_ast.extend(quote! {
|
|
|
<span class="boring"> field_idx: # field_ty::default(),
|
|
|
</span> });
|
|
|
}else{
|
|
|
//对于命名字段，都需要添加 `#field_name: #field_type::default(),` 这样的代码
|
|
|
field_ast.extend(quote! {
|
|
|
<span class="boring"> field_id: # field_ty::default(),
|
|
|
</span> });
|
|
|
}
|
|
|
}
|
|
|
|
|
|
quote! {
|
|
|
impl Default for # id {
|
|
|
fn default() -> Self {
|
|
|
Self {
|
|
|
<span class="boring"> field_ast
|
|
|
</span> }
|
|
|
}
|
|
|
}
|
|
|
}.into()
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>然后来写使用代码:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">#[derive(MyDefault)]
|
|
|
struct SomeData (u32,String);
|
|
|
|
|
|
#[derive(MyDefault)]
|
|
|
struct User {
|
|
|
name: String,
|
|
|
data: SomeData,
|
|
|
}
|
|
|
|
|
|
fn main() {
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
<p>然后我们先展开代码看一看</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">struct SomeData(u32, String);
|
|
|
impl Default for SomeData {
|
|
|
fn default() -> Self {
|
|
|
Self {
|
|
|
0: u32::default(),
|
|
|
1: String::default(),
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
struct User {
|
|
|
name: String,
|
|
|
data: SomeData,
|
|
|
}
|
|
|
impl Default for User {
|
|
|
fn default() -> Self {
|
|
|
Self {
|
|
|
name: String::default(),
|
|
|
data: SomeData::default(),
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
fn main() {}</code></pre></pre>
|
|
|
<p>展开的代码符合预期，然后我们修改一下使用代码并测试结果</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">#[derive(MyDefault, Debug)]
|
|
|
struct SomeData (u32,String);
|
|
|
|
|
|
#[derive(MyDefault, Debug)]
|
|
|
struct User {
|
|
|
name: String,
|
|
|
data: SomeData,
|
|
|
}
|
|
|
|
|
|
fn main() {
|
|
|
println!("{:?}", User::default());
|
|
|
}</code></pre></pre>
|
|
|
<p>执行</p>
|
|
|
<pre><code class="language-shell">$ cargo run
|
|
|
|
|
|
Running `target/debug/aaa`
|
|
|
User { name: "", data: SomeData(0, "") }
|
|
|
</code></pre>
|
|
|
<p>接下来，再来看看过程宏的另外两种类型跟 <code>derive</code> 类型有何区别。</p>
|
|
|
<h2 id="类属性宏attribute-like-macros"><a class="header" href="#类属性宏attribute-like-macros">类属性宏(Attribute-like macros)</a></h2>
|
|
|
<p>类属性过程宏跟 <code>derive</code> 宏类似，但是前者允许我们定义自己的属性。除此之外，<code>derive</code> 只能用于结构体和枚举，而类属性宏可以用于其它类型项，例如函数。</p>
|
|
|
<p>假设我们在开发一个 <code>web</code> 框架，当用户通过 <code>HTTP GET</code> 请求访问 <code>/</code> 根路径时，使用 <code>index</code> 函数为其提供服务:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>#[route(GET, "/")]
|
|
|
fn index() {
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>如上所示，代码功能非常清晰、简洁，这里的 <code>#[route]</code> 属性就是一个过程宏，它的定义函数大概如下：</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span>#[proc_macro_attribute]
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pub fn route(attr: TokenStream, item: TokenStream) -> TokenStream {
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<span class="boring">}</span></code></pre></pre>
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<p>与 <code>derive</code> 宏不同，类属性宏的定义函数有两个参数：</p>
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<ul>
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<li>第一个参数时用于说明属性包含的内容：<code>Get, "/"</code> 部分</li>
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<li>第二个是属性所标注的类型项，在这里是 <code>fn index() {...}</code>，注意，函数体也被包含其中</li>
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</ul>
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<p>除此之外，类属性宏跟 <code>derive</code> 宏的工作方式并无区别：创建一个包，类型是 <code>proc-macro</code>，接着实现一个函数用于生成想要的代码。</p>
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<h2 id="类函数宏function-like-macros"><a class="header" href="#类函数宏function-like-macros">类函数宏(Function-like macros)</a></h2>
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<p>类函数宏可以让我们定义像函数那样调用的宏，从这个角度来看，它跟声明宏 <code>macro_rules</code> 较为类似。</p>
|
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<p>区别在于，<code>macro_rules</code> 的定义形式与 <code>match</code> 匹配非常相像，而类函数宏的定义形式则类似于之前讲过的两种过程宏:</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span>#[proc_macro]
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pub fn sql(input: TokenStream) -> TokenStream {
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<span class="boring">}</span></code></pre></pre>
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<p>而使用形式则类似于函数调用:</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span>let sql = sql!(SELECT * FROM posts WHERE id=1);
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<span class="boring">}</span></code></pre></pre>
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<p>大家可能会好奇，为何我们不使用声明宏 <code>macro_rules</code> 来定义呢？原因是这里需要对 <code>SQL</code> 语句进行解析并检查其正确性，这个复杂的过程是 <code>macro_rules</code> 难以对付的，<strong>而过程宏相比起来就会灵活的多</strong>。</p>
|
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<h2 id="补充学习资料"><a class="header" href="#补充学习资料">补充学习资料</a></h2>
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<ol>
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<li><a href="https://github.com/dtolnay/proc-macro-workshop">dtolnay/proc-macro-workshop</a>，学习如何编写过程宏</li>
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<li><a href="https://veykril.github.io/tlborm/">The Little Book of Rust Macros</a>，学习如何编写声明宏 <code>macro_rules!</code></li>
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<li><a href="https://crates.io/crates/syn">syn</a> 和 <a href="https://crates.io/crates/quote">quote</a> ，用于编写过程宏的包，它们的文档有很多值得学习的东西</li>
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<li><a href="https://www.reddit.com/r/rust/comments/rjumsg/any_good_resources_for_learning_rust_macros/">Structuring, testing and debugging procedural macro crates</a>，从测试、debug、结构化的角度来编写过程宏</li>
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<li><a href="https://blog.turbo.fish">blog.turbo.fish</a>，里面的过程宏系列文章值得一读</li>
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<li><a href="https://zjp-cn.github.io/tlborm/">Rust 宏小册中文版</a>，非常详细的解释了宏各种知识</li>
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</ol>
|
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<h2 id="总结"><a class="header" href="#总结">总结</a></h2>
|
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<p>Rust 中的宏主要分为两大类：声明宏和过程宏。</p>
|
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<p>声明宏目前使用 <code>macro_rules</code> 进行创建，它的形式类似于 <code>match</code> 匹配，对于用户而言，可读性和维护性都较差。由于其存在的问题和限制，在未来， <code>macro_rules</code> 会被 <code>deprecated</code>，Rust 会使用一个新的声明宏来替代它。</p>
|
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<p>而过程宏的定义更像是我们平时写函数的方式，因此它更加灵活，它分为三种类型：<code>derive</code> 宏、类属性宏、类函数宏，具体在文中都有介绍。</p>
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<p>虽然 Rust 中的宏很强大，但是它并不应该成为我们的常规武器，原因是它会影响 Rust 代码的可读性和可维护性，我相信没有几个人愿意去维护别人写的宏 ：）</p>
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<p>因此，大家应该熟悉宏的使用场景，但是不要滥用，当你真的需要时，再回来查看本章了解实现细节，这才是最完美的使用方式。</p>
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