mirror of
https://github.com/google/comprehensive-rust.git
synced 2025-05-19 17:03:13 +02:00
Martin Geisler
GitHub
parent
3e26c0feed
commit
86a4bb4f89
270
po/zh-CN.po
270
po/zh-CN.po
@ -5382,13 +5382,15 @@ msgstr ""
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#: src/enums.md:1
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msgid "# Enums"
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msgstr ""
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msgstr "# 枚举"
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#: src/enums.md:3
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msgid ""
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"The `enum` keyword allows the creation of a type which has a few\n"
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"different variants:"
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msgstr ""
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"`enum` 关键字允许创建具有几个\n"
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"不同变体的类型："
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#: src/enums.md:6
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msgid ""
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@ -5418,7 +5420,7 @@ msgid ""
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"```"
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msgstr ""
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#: src/enums.md:35
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#: src/enums.md:36
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msgid ""
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"* Enumerations allow you to collect a set of values under one type\n"
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"* This page offers an enum type `CoinFlip` with two variants `Heads` and "
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@ -5431,10 +5433,19 @@ msgid ""
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"structs but then they wouldn’t be the same type as they would if they were "
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"all defined in an enum. "
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msgstr ""
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"* 枚举允许你从一种类型下收集一组值\n"
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"* 本页提供了一个枚举类型 `CoinFlip`，其中包含 `Heads` 和`Tail`两个变体。在使"
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"用变体时，你可能会注意到命名空间。\n"
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"* 这可能是比较结构体和枚举的好时机：\n"
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" * 在这两者中，你可以获得一个不含字段的简单版本（单位结构体），或一个包含不"
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"同类型字段的版本（变体载荷）。\n"
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" * 在这两者中，关联的函数都在 `impl` 块中定义。\n"
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" * 你甚至可以使用单独的结构体实现枚举的不同变体，但这样一来，如果它们都已在"
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"枚举中定义，类型与之前也不一样。"
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#: src/enums/variant-payloads.md:1
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msgid "# Variant Payloads"
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msgstr ""
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msgstr "# 变体载荷"
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#: src/enums/variant-payloads.md:3
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msgid ""
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@ -5442,6 +5453,8 @@ msgid ""
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"the\n"
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"`match` statement to extract the data from each variant:"
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msgstr ""
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"你可以定义更丰富的枚举，其中变体会携带数据。然后，你可以使用\n"
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"`match` 语句从每个变体中提取数据："
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#: src/enums/variant-payloads.md:6
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msgid ""
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@ -5472,6 +5485,32 @@ msgid ""
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"}\n"
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"```"
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msgstr ""
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"```rust,editable\n"
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"enum WebEvent {\n"
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" PageLoad, // Variant without payload\n"
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" KeyPress(char), // Tuple struct variant\n"
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" Click { x: i64, y: i64 }, // Full struct variant\n"
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"}\n"
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"\n"
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"#[rustfmt::skip]\n"
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"fn inspect(event: WebEvent) {\n"
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" match event {\n"
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" WebEvent::PageLoad => println!(\"page loaded\"),\n"
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" WebEvent::KeyPress(c) => println!(\"pressed '{c}'\"),\n"
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" WebEvent::Click { x, y } => println!(\"clicked at x={x}, y={y}\"),\n"
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" }\n"
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"}\n"
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"\n"
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"fn main() {\n"
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" let load = WebEvent::PageLoad;\n"
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" let press = WebEvent::KeyPress('x');\n"
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" let click = WebEvent::Click { x: 20, y: 80 };\n"
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"\n"
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" inspect(load);\n"
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" inspect(press);\n"
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" inspect(click);\n"
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"}\n"
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"```"
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#: src/enums/variant-payloads.md:35
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msgid ""
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@ -5497,16 +5536,30 @@ msgid ""
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"cannot implement traits, for example. \n"
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" "
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msgstr ""
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"* 枚举变体中的值只有在被模式匹配后，才可访问。模式将引用绑定到 `=>` 之后"
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"的“match 分支”中的字段。\n"
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" * 表达式会从上到下与模式匹配。没有像 C 或 C++ 中那样的跳转。\n"
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" * 匹配表达式拥有一个值。值是 match 分支中被执行的最后一个表达式。\n"
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" * 从顶部开始，查找与该值匹配的模式，然后沿箭头运行代码。一旦找到匹配，我们"
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"便会停止。\n"
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"* 展示搜索不详尽时会发生的情况。请注意 Rust 编译器的优势，即确认所有情况何时"
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"都得到了处理。\n"
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"* `match` 会检查 `enum` 中的隐藏的判别字段。\n"
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"* 可以通过调用 `std::mem::discriminant()` 来检索判别\n"
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" * 这很有用，例如如果为结构体实现 `PartialEq`，比较字段值不会影响等式。\n"
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"* `WebEvent::Click { ... }` 与含顶层 `struct Click { ... }` 的 `WebEvent::"
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"Click(Click)` 不完全相同。例如，内嵌版本无法实现 trait。\n"
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" "
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#: src/enums/sizes.md:1
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msgid "# Enum Sizes"
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msgstr ""
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msgstr "# 枚举大小"
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#: src/enums/sizes.md:3
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msgid ""
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"Rust enums are packed tightly, taking constraints due to alignment into "
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"account:"
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msgstr ""
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msgstr "Rust 枚举被紧密地打包，考虑到了对齐的影响，因此存在一些限制："
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#: src/enums/sizes.md:5
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msgid ""
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@ -5530,12 +5583,32 @@ msgid ""
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"}\n"
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"```"
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msgstr ""
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"```rust,editable\n"
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"use std::mem::{align_of, size_of};\n"
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"\n"
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"macro_rules! dbg_size {\n"
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" ($t:ty) => {\n"
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" println!(\"{}: size {} bytes, align: {} bytes\",\n"
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" stringify!($t), size_of::<$t>(), align_of::<$t>());\n"
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" };\n"
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"}\n"
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"\n"
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"enum Foo {\n"
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" A,\n"
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" B,\n"
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"}\n"
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"\n"
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"fn main() {\n"
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" dbg_size!(Foo);\n"
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"}\n"
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"```"
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#: src/enums/sizes.md:25
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msgid ""
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"* See the [Rust Reference](https://doc.rust-lang.org/reference/type-layout."
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"html)."
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msgstr ""
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"* 请参阅 [Rust 引用](https://doc.rust-lang.org/reference/type-layout.html)。"
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#: src/enums/sizes.md:31
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msgid ""
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@ -5680,6 +5753,139 @@ msgid ""
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" }\n"
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" ```"
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msgstr ""
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" * 在内部，Rust 使用字段（判别）来跟踪枚举变体。\n"
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"\n"
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" * 你可以根据需要控制判别（例如，与 C 的兼容性）：\n"
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" \n"
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" ```rust,editable\n"
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" #[repr(u32)]\n"
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" enum Bar {\n"
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" A, // 0\n"
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" B = 10000,\n"
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" C, // 10001\n"
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" }\n"
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" \n"
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" fn main() {\n"
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" println!(\"A: {}\", Bar::A as u32);\n"
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" println!(\"B: {}\", Bar::B as u32);\n"
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" println!(\"C: {}\", Bar::C as u32);\n"
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" }\n"
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" ```\n"
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"\n"
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" 如果不使用 `repr`，判别类型会占用 2 个字节，因为 10001 是一个 2\n"
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"个字节的数值。\n"
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"\n"
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"\n"
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" * 试试其他类型，例如：\n"
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" \n"
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" * `dbg_size!(bool)`：大小占用 1 个字节，对齐占用 1 个字节；\n"
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" * `dbg_size!(Option<bool>)`：大小占用 1 个字节，对齐占用 1 个字节（小众"
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"优化，请参阅下文）；\n"
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" * `dbg_size!(&i32)`：大小占用 8 个字节，对齐占用 8 个字节（在 64 位设备"
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"上）；\n"
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" * `dbg_size!(Option<&i32>)`：大小占用 8 个字节，对齐占用 8 个字节（Null "
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"指针优化，请参阅下文）。\n"
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"\n"
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" * 小众优化：Rust 将对枚举判别合并使用\n"
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"未使用的位模式。\n"
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"\n"
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" * Null 指针优化：对于[某些\n"
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"类型](https://doc.rust-lang.org/std/option/#representation)，Rust 保证\n"
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"`size_of::<T>()` 等效于 `size_of::<Option<T>>()`。\n"
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"\n"
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" 如果你想展示位表示方式在实践中“可能”会是什么样子，请参考示例代码。\n"
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" 请务必注意，编译器对此表示法不提供任何保证，因此这是完全不安全的。\n"
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"\n"
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" ```rust,editable\n"
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" use std::mem::transmute;\n"
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"\n"
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" macro_rules! dbg_bits {\n"
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" ($e:expr, $bit_type:ty) => {\n"
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" println!(\"- {}: {:#x}\", stringify!($e), transmute::<_, "
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"$bit_type>($e));\n"
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" };\n"
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" }\n"
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"\n"
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" fn main() {\n"
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" // TOTALLY UNSAFE. Rust provides no guarantees about the bitwise\n"
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" // representation of types.\n"
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" unsafe {\n"
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" println!(\"Bitwise representation of bool\");\n"
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" dbg_bits!(false, u8);\n"
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" dbg_bits!(true, u8);\n"
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"\n"
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" println!(\"Bitwise representation of Option<bool>\");\n"
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" dbg_bits!(None::<bool>, u8);\n"
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" dbg_bits!(Some(false), u8);\n"
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" dbg_bits!(Some(true), u8);\n"
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"\n"
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" println!(\"Bitwise representation of Option<Option<bool>>\");\n"
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" dbg_bits!(Some(Some(false)), u8);\n"
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" dbg_bits!(Some(Some(true)), u8);\n"
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" dbg_bits!(Some(None::<bool>), u8);\n"
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" dbg_bits!(None::<Option<bool>>, u8);\n"
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"\n"
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" println!(\"Bitwise representation of Option<&i32>\");\n"
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" dbg_bits!(None::<&i32>, usize);\n"
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" dbg_bits!(Some(&0i32), usize);\n"
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" }\n"
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" }\n"
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" ```\n"
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"\n"
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" 如果你想讨论当我们把 256 个以上的 `Option` 串联在一起时会发生什么，可以"
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"用更复杂的示例。\n"
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"\n"
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" ```rust,editable\n"
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" #![recursion_limit = \"1000\"]\n"
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"\n"
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" use std::mem::transmute;\n"
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" \n"
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" macro_rules! dbg_bits {\n"
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" ($e:expr, $bit_type:ty) => {\n"
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" println!(\"- {}: {:#x}\", stringify!($e), transmute::<_, "
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"$bit_type>($e));\n"
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" };\n"
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" }\n"
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"\n"
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" // 用于封装 2^n Some() 中的值的宏，其中 n 的 \"@\" 符号的个数。\n"
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" // 增加递归限制需要评估这个宏。\n"
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" macro_rules! many_options {\n"
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" ($value:expr) => { Some($value) };\n"
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" ($value:expr, @) => {\n"
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" Some(Some($value))\n"
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" };\n"
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" ($value:expr, @ $($more:tt)+) => {\n"
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" many_options!(many_options!($value, $($more)+), $($more)+)\n"
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" };\n"
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" }\n"
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"\n"
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" fn main() {\n"
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" // TOTALLY UNSAFE. Rust provides no guarantees about the bitwise\n"
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" // representation of types.\n"
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" unsafe {\n"
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" assert_eq!(many_options!(false), Some(false));\n"
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" assert_eq!(many_options!(false, @), Some(Some(false)));\n"
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" assert_eq!(many_options!(false, @@), "
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"Some(Some(Some(Some(false)))));\n"
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"\n"
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" println!(\"Bitwise representation of a chain of 128 Option's."
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"\");\n"
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" dbg_bits!(many_options!(false, @@@@@@@), u8);\n"
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" dbg_bits!(many_options!(true, @@@@@@@), u8);\n"
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"\n"
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" println!(\"Bitwise representation of a chain of 256 Option's."
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"\");\n"
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" dbg_bits!(many_options!(false, @@@@@@@@), u16);\n"
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" dbg_bits!(many_options!(true, @@@@@@@@), u16);\n"
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"\n"
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" println!(\"Bitwise representation of a chain of 257 Option's."
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"\");\n"
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" dbg_bits!(many_options!(Some(false), @@@@@@@@), u16);\n"
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" dbg_bits!(many_options!(Some(true), @@@@@@@@), u16);\n"
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" dbg_bits!(many_options!(None::<bool>, @@@@@@@@), u16);\n"
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" }\n"
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" }\n"
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" ```"
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#: src/methods.md:3
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msgid ""
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@ -19571,3 +19777,57 @@ msgid ""
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"}\n"
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"```"
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msgstr ""
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#: src/enums.md:6
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msgid ""
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"```rust,editable\n"
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"fn generate_random_number() -> i32 {\n"
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" // Implementation based on https://xkcd.com/221/\n"
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" 4 // Chosen by fair dice roll. Guaranteed to be random.\n"
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"}\n"
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"\n"
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"#[derive(Debug)]\n"
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"enum CoinFlip {\n"
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" Heads,\n"
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" Tails,\n"
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"}\n"
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"\n"
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"fn flip_coin() -> CoinFlip {\n"
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" let random_number = generate_random_number();\n"
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" if random_number % 2 == 0 {\n"
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" return CoinFlip::Heads;\n"
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" } else {\n"
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" return CoinFlip::Tails;\n"
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" }\n"
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"}\n"
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"\n"
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"fn main() {\n"
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" println!(\"You got: {:?}\", flip_coin());\n"
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"}\n"
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"```"
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msgstr ""
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"```rust,editable\n"
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"fn generate_random_number() -> i32 {\n"
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" // Implementation based on https://xkcd.com/221/\n"
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" 4 // Chosen by fair dice roll. Guaranteed to be random.\n"
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"}\n"
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"\n"
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"#[derive(Debug)]\n"
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"enum CoinFlip {\n"
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" Heads,\n"
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" Tails,\n"
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"}\n"
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"\n"
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"fn flip_coin() -> CoinFlip {\n"
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" let random_number = generate_random_number();\n"
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" if random_number % 2 == 0 {\n"
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" return CoinFlip::Heads;\n"
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" } else {\n"
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" return CoinFlip::Tails;\n"
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" }\n"
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"}\n"
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"\n"
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"fn main() {\n"
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" println!(\"You got: {:?}\", flip_coin());\n"
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"}\n"
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"```"
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