From 76a71eb7d6703630abbcf934b89c21753af99b79 Mon Sep 17 00:00:00 2001
From: sunface <cto@188.com>
Date: Thu, 17 Mar 2022 13:41:40 +0800
Subject: [PATCH] =?UTF-8?q?rename=20Rust=E7=BC=96=E7=A8=8B=E5=AD=A6?=
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---
 README.md                            |  4 +-
 src/SUMMARY.md                       |  1 -
 src/about-book.md                    |  2 +-
 src/too-many-lists/deque/iterator.md | 63 ++++++++++++++++++++++++++++
 4 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 0f862b49..53b3b840 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@
 </div>
 
 - 在线阅读
-  - Rust编程学院： [https://course.rs](https://course.rs)
+  - 官网： [https://course.rs](https://course.rs)
   - 知乎专栏： [支持章节内目录跳转，很好用!](https://www.zhihu.com/column/c_1452781034895446017)
   
 - 配套项目  
@@ -50,7 +50,7 @@
 
 
 ## 学习社区
-为了帮助大家更好的学习和交流 Rust，我们建立了一个社区：**Rust编程学院**。
+为了帮助大家更好的学习和交流 Rust，我们建立了一个社区：**Rust语言学习社区**。
 
 QQ群 1009730433， 欢迎大家加入，一起 happy，一起进步。
 
diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index 2e400eb1..00182480 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -240,7 +240,6 @@
     - [编译器优化 todo](profiling/compiler/optimization/intro.md)
       - [Option 枚举 todo](profiling/compiler/optimization/option.md)
 
-
 - [标准库解析 todo](std/intro.md)
   - [标准库使用最佳时间 todo](std/search.md)
   - [Vector 常用方法 todo](std/vector.md)
diff --git a/src/about-book.md b/src/about-book.md
index fcbfa616..6c577d8b 100644
--- a/src/about-book.md
+++ b/src/about-book.md
@@ -50,7 +50,7 @@
 
 
 ## 学习社区
-为了帮助大家更好的学习和交流 Rust，我们建立了一个社区：**Rust编程学院**。
+为了帮助大家更好的学习和交流 Rust，我们建立了一个社区：**Rust学习社区**。
 
 QQ群 1009730433， 欢迎大家加入，一起 happy，一起进步。
 
diff --git a/src/too-many-lists/deque/iterator.md b/src/too-many-lists/deque/iterator.md
index 51967d55..199e69e2 100644
--- a/src/too-many-lists/deque/iterator.md
+++ b/src/too-many-lists/deque/iterator.md
@@ -24,3 +24,66 @@ impl<T> Iterator for IntoIter<T> {
 
 答案是: `DoubleEndedIterator`，它继承自 `Iterator`( 通过 [`supertrait`](https://course.rs/basic/trait/advance-trait.html?highlight=supertrait#特征定义中的特征约束) )，因此意味着要实现该特征，首先需要实现 `Iterator`。
 
+这样只要为 `DoubleEndedIterator` 实现 `next_back` 方法，就可以支持双向迭代了: `Iterator` 的 `next` 方法从前往后，而 `next_back` 从后向前。
+
+```rust
+impl<T> DoubleEndedIterator for IntoIter<T> {
+    fn next_back(&mut self) -> Option<T> {
+        self.0.pop_back()
+    }
+}
+```
+
+测试下:
+```rust
+#[test]
+fn into_iter() {
+    let mut list = List::new();
+    list.push_front(1); list.push_front(2); list.push_front(3);
+
+    let mut iter = list.into_iter();
+    assert_eq!(iter.next(), Some(3));
+    assert_eq!(iter.next_back(), Some(1));
+    assert_eq!(iter.next(), Some(2));
+    assert_eq!(iter.next_back(), None);
+    assert_eq!(iter.next(), None);
+}
+```
+
+```shell
+cargo test
+
+     Running target/debug/lists-5c71138492ad4b4a
+
+running 11 tests
+test fourth::test::basics ... ok
+test fourth::test::peek ... ok
+test fourth::test::into_iter ... ok
+test first::test::basics ... ok
+test second::test::basics ... ok
+test second::test::iter ... ok
+test second::test::iter_mut ... ok
+test third::test::iter ... ok
+test third::test::basics ... ok
+test second::test::into_iter ... ok
+test second::test::peek ... ok
+
+test result: ok. 11 passed; 0 failed; 0 ignored; 0 measured
+```
+
+## Iter
+这里又要用到糟糕的 `Ref`:
+```rust
+pub struct Iter<'a, T>(Option<Ref<'a, Node<T>>>);
+
+impl<T> List<T> {
+    pub fn iter(&self) -> Iter<T> {
+        Iter(self.head.as_ref().map(|head| head.borrow()))
+    }
+}
+```
+
+```shell
+> cargo build
+```
+