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<ol class="chapter"><li class="chapter-item expanded affix "><a href="title-page.html">Rust 程序设计语言</a></li><li class="chapter-item expanded affix "><a href="foreword.html">前言</a></li><li class="chapter-item expanded affix "><a href="ch00-00-introduction.html">简介</a></li><li class="chapter-item expanded "><a href="ch01-00-getting-started.html"><strong aria-hidden="true">1.</strong> 入门指南</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch01-01-installation.html"><strong aria-hidden="true">1.1.</strong> 安装</a></li><li class="chapter-item expanded "><a href="ch01-02-hello-world.html"><strong aria-hidden="true">1.2.</strong> Hello, World!</a></li><li class="chapter-item expanded "><a href="ch01-03-hello-cargo.html"><strong aria-hidden="true">1.3.</strong> Hello, Cargo!</a></li></ol></li><li class="chapter-item expanded "><a href="ch02-00-guessing-game-tutorial.html"><strong aria-hidden="true">2.</strong> 写个猜数字游戏</a></li><li class="chapter-item expanded "><a href="ch03-00-common-programming-concepts.html"><strong aria-hidden="true">3.</strong> 常见编程概念</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch03-01-variables-and-mutability.html"><strong aria-hidden="true">3.1.</strong> 变量与可变性</a></li><li class="chapter-item expanded "><a href="ch03-02-data-types.html"><strong aria-hidden="true">3.2.</strong> 数据类型</a></li><li class="chapter-item expanded "><a href="ch03-03-how-functions-work.html"><strong aria-hidden="true">3.3.</strong> 函数</a></li><li class="chapter-item expanded "><a href="ch03-04-comments.html"><strong aria-hidden="true">3.4.</strong> 注释</a></li><li class="chapter-item expanded "><a href="ch03-05-control-flow.html"><strong aria-hidden="true">3.5.</strong> 控制流</a></li></ol></li><li class="chapter-item expanded "><a href="ch04-00-understanding-ownership.html"><strong aria-hidden="true">4.</strong> 认识所有权</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch04-01-what-is-ownership.html"><strong aria-hidden="true">4.1.</strong> 什么是所有权?</a></li><li class="chapter-item expanded "><a href="ch04-02-references-and-borrowing.html"><strong aria-hidden="true">4.2.</strong> 引用与借用</a></li><li class="chapter-item expanded "><a href="ch04-03-slices.html"><strong aria-hidden="true">4.3.</strong> Slice 类型</a></li></ol></li><li class="chapter-item expanded "><a href="ch05-00-structs.html"><strong aria-hidden="true">5.</strong> 使用结构体组织相关联的数据</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch05-01-defining-structs.html"><strong aria-hidden="true">5.1.</strong> 结构体的定义和实例化</a></li><li class="chapter-item expanded "><a href="ch05-02-example-structs.html"><strong aria-hidden="true">5.2.</strong> 结构体示例程序</a></li><li class="chapter-item expanded "><a href="ch05-03-method-syntax.html"><strong aria-hidden="true">5.3.</strong> 方法语法</a></li></ol></li><li class="chapter-item expanded "><a href="ch06-00-enums.html"><strong aria-hidden="true">6.</strong> 枚举和模式匹配</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch06-01-defining-an-enum.html"><strong aria-hidden="true">6.1.</strong> 枚举的定义</a></li><li class="chapter-item expanded "><a href="ch06-02-match.html"><strong aria-hidden="true">6.2.</strong> match 控制流结构</a></li><li class="chapter-item expanded "><a href="ch06-03-if-let.html"><strong aria-hidden="true">6.3.</strong> if let 简洁控制流</a></li></ol></li><li class="chapter-item expanded "><a href="ch07-00-managing-growing-projects-with-packages-crates-and-modules.html"><strong aria-hidden="true">7.</strong> 使用包、Crate 和模块管理不断增长的项目</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch07-01-packages-and-crates.html"><strong aria-hidden="true">7.1.</strong> 包和 Crate</a></li><li class="chapter-item expanded "><a href="ch07-02-defining-modules-to-control-scope-and-privacy.html"><strong aria-hidden="true">7.2.</strong> 定义模块来控制作用域与私有性</a></li><li class="chapter-item expanded "><a href="ch07-03-paths-for-referring-to-an-item-in-the-module-tree.html"><strong aria-hidden="true">7.3.</strong> 引用模块项目的路径</a></li><li class="chapter-item expanded "><a href="ch07-04-bringing-paths-into-scope-with-the-use-keyword.html"><strong aria-hidden="true">7.4.</strong> 使用 use 关键字将路径引入作用域</a></li><li class="chapter-item expanded "><a href="ch07-05-separating-modules-into-different-files.html"><strong aria-hidden="true">7.5.</strong> 将模块拆分成多个文件</a></li></ol></li><li class="chapter-item expanded "><a href="ch08-00-common-collections.html"><strong aria-hidden="true">8.</strong> 常见集合</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch08-01-vectors.html"><strong aria-hidden="true">8.1.</strong> 使用 Vector 储存列表</a></li><li class="chapter-item expanded "><a href="ch08-02-strings.html"><strong aria-hidden="true">8.2.</strong> 使用字符串储存 UTF-8 编码的文本</a></li><li class="chapter-item expanded "><a href="ch08-03-hash-maps.html"><strong aria-hidden="true">8.3.</strong> 使用 Hash Map 储存键值对</a></li></ol></li><li class="chapter-item expanded "><a href="ch09-00-error-handling.html"><strong aria-hidden="true">9.</strong> 错误处理</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch09-01-unrecoverable-errors-with-panic.html"><strong aria-hidden="true">9.1.</strong> 用 panic! 处理不可恢复的错误</a></li><li class="chapter-item expanded "><a href="ch09-02-recoverable-errors-with-result.html"><strong aria-hidden="true">9.2.</strong> 用 Result 处理可恢复的错误</a></li><li class="chapter-item expanded "><a href="ch09-03-to-panic-or-not-to-panic.html"><strong aria-hidden="true">9.3.</strong> 要不要 panic!</a></li></ol></li><li class="chapter-item expanded "><a href="ch10-00-generics.html"><strong aria-hidden="true">10.</strong> 泛型、Trait 和生命周期</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch10-01-syntax.html"><strong aria-hidden="true">10.1.</strong> 泛型数据类型</a></li><li class="chapter-item expanded "><a href="ch10-02-traits.html"><strong aria-hidden="true">10.2.</strong> Trait定义共同行为</a></li><li class="chapter-item expanded "><a href="ch10-03-lifetime-syntax.html"><strong aria-hidden="true">10.3.</strong> 生命周期确保引用有效</a></li></ol></li><li class="chapter-item expanded "><a href="ch11-00-testing.html"><strong aria-hidden="true">11.</strong> 编写自动化测试</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch11-01-writing-tests.html"><strong aria-hidden="true">11.1.</strong> 如何编写测试</a></li><li class="chapter-item expanded "><a href="ch11-02-running-tests.html"><strong aria-hidden="true">11.2.</strong> 控制测试如何运行</a></li><li class="chapter-item expanded "><a href="ch11-03-test-organization.html"><strong aria-hidden="true">11.3.</strong> 测试的组织结构</a></li></ol></li><li class="chapter-item expanded "><a href="ch12-00-an-io-project.html"><strong aria-hidden="true">12.</strong> 一个 I/O 项目:构建命令行程序</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch12-01-accepting-command-line-arguments.html"><strong aria-hidden="true">12.1.</strong> 接受命令行参数</a></li><li class="chapter-item expanded "><a href="ch12-02-reading-a-file.html"><strong aria-hidden="true">12.2.</strong> 读取文件</a></li><li class="chapter-item expanded "><a href="ch12-03-improving-error-handling-and-modularity.html"><strong aria-hidden="true">12.3.</strong> 重构以改进模块化与错误处理</a></li><li class="chapter-item expanded "><a href="ch12-04-testing-the-librarys-functionality.html"><strong aria-hidden="true">12.4.</strong> 采用测试驱动开发完善库的功能</a></li><li class="chapter-item expanded "><a href="ch12-05-working-with-environment-variables.html"><strong aria-hidden="true">12.5.</strong> 处理环境变量</a></li><li class="chapter-item expanded "><a href="ch12-06-writing-to-stderr-instead-of-stdout.html"><strong aria-hidden="true">12.6.</strong> 将错误信息输出到标准错误而不是标准输出</a></li></ol></li><li class="chapter-item expanded "><a href="ch13-00-functional-features.html"><strong aria-hidden="true">13.</strong> Rust 中的函数式语言功能:迭代器与闭包</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch13-01-closures.html"><strong aria-hidden="true">13.1.</strong> 闭包:可以捕获其环境的匿名函数</a></li><li class="chapter-item expanded "><a href="ch13-02-iterators.html"><strong aria-hidden="true">13.2.</strong> 使用迭代器处理元素序列</a></li><li class="chapter-item expanded "><a href="ch13-03-improving-our-io-project.html"><strong aria-hidden="true">13.3.</strong> 改进之前的 I/O 项目</a></li><li class="chapter-item expanded "><a href="ch13-04-performance.html"><strong aria-hidden="true">13.4.</strong> 性能比较:循环对迭代器</a></li></ol></li><li class="chapter-item expanded "><a href="ch14-00-more-about-cargo.html"><strong aria-hidden="true">14.</strong> 更多关于 Cargo 和 Crates.io 的内容</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch14-01-release-profiles.html"><strong aria-hidden="true">14.1.</strong> 采用发布配置自定义构建</a></li><li class="chapter-item expanded "><a href="ch14-02-publishing-to-crates-io.html"><strong aria-hidden="true">14.2.</strong> 将 crate 发布到 Crates.io</a></li><li class="chapter-item expanded "><a href="ch14-03-cargo-workspaces.html"><strong aria-hidden="true">14.3.</strong> Cargo 工作空间</a></li><li class="chapter-item expanded "><a href="ch14-04-installing-binaries.html"><strong aria-hidden="true">14.4.</strong> 使用 cargo install 安装二进制文件</a></li><li class="chapter-item expanded "><a href="ch14-05-extending-cargo.html"><strong aria-hidden="true">14.5.</strong> Cargo 自定义扩展命令</a></li></ol></li><li class="chapter-item expanded "><a href="ch15-00-smart-pointers.html"><strong aria-hidden="true">15.</strong> 智能指针</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch15-01-box.html"><strong aria-hidden="true">15.1.</strong> 使用 Box&lt;T&gt; 指向堆上数据</a></li><li class="chapter-item expanded "><a href="ch15-02-deref.html"><strong aria-hidden="true">15.2.</strong> 使用 Deref Trait 将智能指针当作常规引用处理</a></li><li class="chapter-item expanded "><a href="ch15-03-drop.html"><strong aria-hidden="true">15.3.</strong> 使用 Drop Trait 运行清理代码</a></li><li class="chapter-item expanded "><a href="ch15-04-rc.html"><strong aria-hidden="true">15.4.</strong> Rc&lt;T&gt; 引用计数智能指针</a></li><li class="chapter-item expanded "><a href="ch15-05-interior-mutability.html"><strong aria-hidden="true">15.5.</strong> RefCell&lt;T&gt; 与内部可变性模式</a></li><li class="chapter-item expanded "><a href="ch15-06-reference-cycles.html"><strong aria-hidden="true">15.6.</strong> 引用循环会导致内存泄漏</a></li></ol></li><li class="chapter-item expanded "><a href="ch16-00-concurrency.html"><strong aria-hidden="true">16.</strong> 无畏并发</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch16-01-threads.html"><strong aria-hidden="true">16.1.</strong> 使用线程同时地运行代码</a></li><li class="chapter-item expanded "><a href="ch16-02-message-passing.html"><strong aria-hidden="true">16.2.</strong> 使用消息传递在线程间通信</a></li><li class="chapter-item expanded "><a href="ch16-03-shared-state.html"><strong aria-hidden="true">16.3.</strong> 共享状态并发</a></li><li class="chapter-item expanded "><a href="ch16-04-extensible-concurrency-sync-and-send.html"><strong aria-hidden="true">16.4.</strong> 使用 Sync 与 Send Traits 的可扩展并发</a></li></ol></li><li class="chapter-item expanded "><a href="ch17-00-oop.html"><strong aria-hidden="true">17.</strong> Rust 的面向对象编程特性</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch17-01-what-is-oo.html"><strong aria-hidden="true">17.1.</strong> 面向对象语言的特点</a></li><li class="chapter-item expanded "><a href="ch17-02-trait-objects.html"><strong aria-hidden="true">17.2.</strong> 顾及不同类型值的 trait 对象</a></li><li class="chapter-item expanded "><a href="ch17-03-oo-design-patterns.html"><strong aria-hidden="true">17.3.</strong> 面向对象设计模式的实现</a></li></ol></li><li class="chapter-item expanded "><a href="ch18-00-patterns.html"><strong aria-hidden="true">18.</strong> 模式与模式匹配</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch18-01-all-the-places-for-patterns.html"><strong aria-hidden="true">18.1.</strong> 所有可能会用到模式的位置</a></li><li class="chapter-item expanded "><a href="ch18-02-refutability.html"><strong aria-hidden="true">18.2.</strong> Refutability可反驳性: 模式是否会匹配失效</a></li><li class="chapter-item expanded "><a href="ch18-03-pattern-syntax.html"><strong aria-hidden="true">18.3.</strong> 模式语法</a></li></ol></li><li class="chapter-item expanded "><a href="ch19-00-advanced-features.html"><strong aria-hidden="true">19.</strong> 高级特征</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch19-01-unsafe-rust.html"><strong aria-hidden="true">19.1.</strong> 不安全的 Rust</a></li><li class="chapter-item expanded "><a href="ch19-03-advanced-traits.html"><strong aria-hidden="true">19.2.</strong> 高级 trait</a></li><li class="chapter-item expanded "><a href="ch19-04-advanced-types.html"><strong aria-hidden="true">19.3.</strong> 高级类型</a></li><li class="chapter-item expanded "><a href="ch19-05-advanced-functions-and-closures.html"><strong aria-hidden="true">19.4.</strong> 高级函数与闭包</a></li><li class="chapter-item expanded "><a href="ch19-06-macros.html"><strong aria-hidden="true">19.5.</strong></a></li></ol></li><li class="chapter-item expanded "><a href="ch20-00-final-project-a-web-server.html"><strong aria-hidden="true">20.</strong> 最后的项目:构建多线程 web server</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch20-01-single-threaded.html"><strong aria-hidden="true">20.1.</strong> 建立单线程 web server</a></li><li class="chapter-item expanded "><a href="ch20-02-multithreaded.html"><strong aria-hidden="true">20.2.</strong> 将单线程 server 变为多线程 server</a></li><li class="chapter-item expanded "><a href="ch20-03-graceful-shutdown-and-cleanup.html"><strong aria-hidden="true">20.3.</strong> 优雅停机与清理</a></li></ol></li><li class="chapter-item expanded "><a href="appendix-00.html"><strong aria-hidden="true">21.</strong> 附录</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="appendix-01-keywords.html"><strong aria-hidden="true">21.1.</strong> A - 关键字</a></li><li class="chapter-item expanded "><a href="appendix-02-operators.html"><strong aria-hidden="true">21.2.</strong> B - 运算符与符号</a></li><li class="chapter-item expanded "><a href="appendix-03-derivable-traits.html"><strong aria-hidden="true">21.3.</strong> C - 可派生的 trait</a></li><li class="chapter-item expanded "><a href="appendix-04-useful-development-tools.html"><strong aria-hidden="true">21.4.</strong> D - 实用开发工具</a></li><li class="chapter-item expanded "><a href="appendix-05-editions.html"><strong aria-hidden="true">21.5.</strong> E - 版本</a></li><li class="chapter-item expanded "><a href="appendix-06-translation.html"><strong aria-hidden="true">21.6.</strong> F - 本书译本</a></li><li class="chapter-item expanded "><a href="appendix-07-nightly-rust.html" class="active"><strong aria-hidden="true">21.7.</strong> G - Rust 是如何开发的与 “Nightly Rust”</a></li></ol></li></ol>
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<h2 id="附录-grust-是如何开发的与-nightly-rust"><a class="header" href="#附录-grust-是如何开发的与-nightly-rust">附录 GRust 是如何开发的与 “Nightly Rust”</a></h2>
<blockquote>
<p><a href="https://github.com/rust-lang/book/blob/main/src/appendix-07-nightly-rust.md">appendix-07-nightly-rust.md</a>
<br />
commit d44317c3122b44fb713aba66cc295dee3453b24b</p>
</blockquote>
<p>本附录介绍 Rust 是如何开发的以及这如何影响作为 Rust 开发者的你。</p>
<h3 id="无停滞稳定"><a class="header" href="#无停滞稳定">无停滞稳定</a></h3>
<p>作为一个语言Rust <strong>十分</strong> 注重代码的稳定性。我们希望 Rust 成为你代码坚实的基础,假如持续地有东西在变,这个希望就实现不了。但与此同时,如果不能实验新功能的话,在发布之前我们又无法发现其中重大的缺陷,而一旦发布便再也没有修改的机会了。</p>
<p>对于这个问题我们的解决方案被称为 “无停滞稳定”“stability without stagnation”其指导性原则是无需担心升级到最新的稳定版 Rust。每次升级应该是无痛的并应带来新功能更少的 bug 和更快的编译速度。</p>
<h3 id="choo-choo-发布通道和发布时刻表riding-the-trains"><a class="header" href="#choo-choo-发布通道和发布时刻表riding-the-trains">Choo, Choo! 发布通道和发布时刻表Riding the Trains</a></h3>
<p>Rust 开发运行于一个 <strong>发布时刻表</strong><em>train schedule</em>)之上。也就是说,所有的开发工作都位于 Rust 仓库的 <code>master</code> 分支。发布采用 software release train 模型,其被用于思科 IOS 等其它软件项目。Rust 有三个 <strong>发布通道</strong><em>release channel</em></p>
<ul>
<li>Nightly</li>
<li>Beta</li>
<li>Stable稳定版</li>
</ul>
<p>大部分 Rust 开发者主要采用稳定版通道,不过希望实验新功能的开发者可能会使用 nightly 或 beta 版。</p>
<p>如下是一个开发和发布过程如何运转的例子:假设 Rust 团队正在进行 Rust 1.5 的发布工作。该版本发布于 2015 年 12 月不过这里只是为了提供一个真实的版本。Rust 新增了一项功能:一个 <code>master</code> 分支的新提交。每天晚上,会产生一个新的 nightly 版本。每天都是发布版本的日子,而这些发布由发布基础设施自动完成。所以随着时间推移,发布轨迹看起来像这样,版本一天一发:</p>
<pre><code class="language-text">nightly: * - - * - - *
</code></pre>
<p>每 6 周时间是准备发布新版本的时候了Rust 仓库的 <code>beta</code> 分支会从用于 nightly 的 <code>master</code> 分支产生。现在,有了两个发布版本:</p>
<pre><code class="language-text">nightly: * - - * - - *
|
beta: *
</code></pre>
<p>大部分 Rust 用户不会主要使用 beta 版本,不过在 CI 系统中对 beta 版本进行测试能够帮助 Rust 发现可能的回归缺陷regression。同时每天仍产生 nightly 发布:</p>
<pre><code class="language-text">nightly: * - - * - - * - - * - - *
|
beta: *
</code></pre>
<p>比如我们发现了一个回归缺陷。好消息是在这些缺陷流入稳定发布之前还有一些时间来测试 beta 版本fix 被合并到 <code>master</code>,为此 nightly 版本得到了修复,接着这些 fix 将 backport 到 <code>beta</code> 分支,一个新的 beta 发布就产生了:</p>
<pre><code class="language-text">nightly: * - - * - - * - - * - - * - - *
|
beta: * - - - - - - - - *
</code></pre>
<p>第一个 beta 版的 6 周后,是发布稳定版的时候了!<code>stable</code> 分支从 <code>beta</code> 分支生成:</p>
<pre><code class="language-text">nightly: * - - * - - * - - * - - * - - * - * - *
|
beta: * - - - - - - - - *
|
stable: *
</code></pre>
<p>好的Rust 1.5 发布了!然而,我们忘了些东西:因为又过了 6 周,我们还需发布 <strong>新版</strong> Rust 的 beta 版Rust 1.6。所以从 <code>beta</code> 生成 <code>stable</code> 分支后,新版的 <code>beta</code> 分支也再次从 <code>nightly</code> 生成:</p>
<pre><code class="language-text">nightly: * - - * - - * - - * - - * - - * - * - *
| |
beta: * - - - - - - - - * *
|
stable: *
</code></pre>
<p>这被称为 “train model”因为每 6 周,一个版本 “离开车站”“leaves the station”不过从 beta 通道到达稳定通道还有一段旅程。</p>
<p>Rust 每 6 周发布一个版本,如时钟般准确。如果你知道了某个 Rust 版本的发布时间就可以知道下个版本的时间6 周后。每 6 周发布版本的一个好的方面是下一班车会来得更快。如果特定版本碰巧缺失某个功能也无需担心:另一个版本很快就会到来!这有助于减少因临近发版时间而偷偷释出未经完善的功能的压力。</p>
<p>多亏了这个过程,你总是可以切换到下一版本的 Rust 并验证是否可以轻易的升级:如果 beta 版不能如期工作,你可以向 Rust 团队报告并在发布稳定版之前得到修复beta 版造成的破坏是非常少见的,不过 <code>rustc</code> 也不过是一个软件,可能会存在 bug。</p>
<h3 id="不稳定功能"><a class="header" href="#不稳定功能">不稳定功能</a></h3>
<p>这个发布模型中另一个值得注意的地方不稳定功能unstable features。Rust 使用一个被称为 “功能标记”“feature flags”的技术来确定给定版本的某个功能是否启用。如果新功能正在积极地开发中其提交到了 <code>master</code>,因此会出现在 nightly 版中,不过会位于一个 <strong>功能标记</strong> 之后。作为用户,如果你希望尝试这个正在开发的功能,则可以在源码中使用合适的标记来开启,不过必须使用 nightly 版。</p>
<p>如果使用的是 beta 或稳定版 Rust则不能使用任何功能标记。这是在新功能被宣布为永久稳定之前获得实用价值的关键。这既满足了希望使用最尖端技术的同学那些坚持稳定版的同学也知道其代码不会被破坏。这就是无停滞稳定。</p>
<p>本书只包含稳定的功能,因为还在开发中的功能仍可能改变,当其进入稳定版时肯定会与编写本书的时候有所不同。你可以在网上获取 nightly 版的文档。</p>
<h3 id="rustup-和-rust-nightly-的职责"><a class="header" href="#rustup-和-rust-nightly-的职责">Rustup 和 Rust Nightly 的职责</a></h3>
<p>Rustup 使得改变不同发布通道的 Rust 更为简单,其在全局或分项目的层次工作。其默认会安装稳定版 Rust。例如为了安装 nightly</p>
<pre><code class="language-console">$ rustup toolchain install nightly
</code></pre>
<p>你会发现 <code>rustup</code> 也安装了所有的 <strong>工具链</strong><em>toolchains</em>Rust 和其相关组件)。如下是一位作者的 Windows 计算机上的例子:</p>
<pre><code class="language-powershell">&gt; rustup toolchain list
stable-x86_64-pc-windows-msvc (default)
beta-x86_64-pc-windows-msvc
nightly-x86_64-pc-windows-msvc
</code></pre>
<p>如你所见,默认是稳定版。大部分 Rust 用户在大部分时间使用稳定版。你可能也会这么做,不过如果你关心最新的功能,可以为特定项目使用 nightly 版。为此,可以在项目目录使用 <code>rustup override</code> 来设置当前目录 <code>rustup</code> 使用 nightly 工具链:</p>
<pre><code class="language-console">$ cd ~/projects/needs-nightly
$ rustup override set nightly
</code></pre>
<p>现在,每次在 <em>~/projects/needs-nightly</em> 调用 <code>rustc</code><code>cargo</code><code>rustup</code> 会确保使用 nightly 版 Rust。在你有很多 Rust 项目时大有裨益!</p>
<h3 id="rfc-过程和团队"><a class="header" href="#rfc-过程和团队">RFC 过程和团队</a></h3>
<p>那么你如何了解这些新功能呢Rust 开发模式遵循一个 <strong>Request For Comments (RFC) 过程</strong>。如果你希望改进 Rust可以编写一个提议也就是 RFC。</p>
<p>任何人都可以编写 RFC 来改进 Rust同时这些 RFC 会被 Rust 团队评审和讨论,他们由很多不同分工的子团队组成。这里是 <a href="https://www.rust-lang.org/governance">Rust 官网上</a> 所有团队的总列表,其包含了项目中每个领域的团队:语言设计、编译器实现、基础设施、文档等。各个团队会阅读相应的提议和评论,编写回复,并最终达成接受或回绝功能的一致。</p>
<p>如果功能被接受了,在 Rust 仓库会打开一个 issue人们就可以实现它。实现功能的人当然可能不是最初提议功能的人当实现完成后其会合并到 <code>master</code> 分支并位于一个功能开关feature gate之后正如 <a href="#%E4%B8%8D%E7%A8%B3%E5%AE%9A%E5%8A%9F%E8%83%BD">“不稳定功能”</a> 部分所讨论的。</p>
<p>在稍后的某个时间,一旦使用 nightly 版的 Rust 团队能够尝试这个功能了,团队成员会讨论这个功能,它如何在 nightly 中工作,并决定是否应该进入稳定版。如果决定继续推进,功能开关会移除,然后这个功能就被认为是稳定的了!乘着“发布的列车”,最终在新的稳定版 Rust 中出现。</p>
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