Merge pull request #890 from qwer252/main

。

listings/ch18-oop/listing-18-07/src/lib.rs

@@ -23,7 +23,7 @@ pub struct Button {
 
 impl Draw for Button {
     fn draw(&self) {
-        // code to actually draw a button
+        // 实际绘制按钮的代码
     }
 }
 // ANCHOR_END: here

listings/ch18-oop/listing-18-08/src/lib.rs

@@ -22,6 +22,6 @@ pub struct Button {
 
 impl Draw for Button {
     fn draw(&self) {
-        // code to actually draw a button
+        // 实际绘制按钮的代码
     }
 }

listings/ch20-advanced-features/listing-20-11/src/main.rs

@@ -1,8 +1,7 @@
 static mut COUNTER: u32 = 0;
 
-/// SAFETY: Calling this from more than a single thread at a time is undefined
+/// SAFETY: 同时在多个线程调用这个方法是未定义的行为，所以你*必须*保证同一时间只
-/// behavior, so you *must* guarantee you only call it from a single thread at
+/// 有一个线程在调用它。
-/// a time.
 unsafe fn add_to_count(inc: u32) {
     unsafe {
         COUNTER += inc;
@@ -11,7 +10,7 @@ unsafe fn add_to_count(inc: u32) {
 
 fn main() {
     unsafe {
-        // SAFETY: This is only called from a single thread in `main`.
+        // SAFETY: 它只在 `main` 这一个线程被调用。
         add_to_count(3);
         println!("COUNTER: {}", *(&raw const COUNTER));
     }

listings/ch20-advanced-features/listing-20-12/src/main.rs

@@ -1,10 +1,10 @@
 // ANCHOR: here
 unsafe trait Foo {
-    // methods go here
+    // 方法在这里
 }
 
 unsafe impl Foo for i32 {
-    // method implementations go here
+    // 方法实现在这里
 }
 // ANCHOR_END: here
 

listings/ch20-advanced-features/listing-20-40/hello_macro/hello_macro_derive/src/lib.rs

@@ -3,10 +3,9 @@ use quote::quote;
 
 #[proc_macro_derive(HelloMacro)]
 pub fn hello_macro_derive(input: TokenStream) -> TokenStream {
-    // Construct a representation of Rust code as a syntax tree
+    // 将 Rust 代码构建成我们可以操作的语法树。
-    // that we can manipulate.
     let ast = syn::parse(input).unwrap();
 
-    // Build the trait implementation.
+    // 生成 trait 的实现。
     impl_hello_macro(&ast)
 }