翻譯Drop

src/SUMMARY.md

@@ -23,7 +23,7 @@
     * [字串](strings.md)
     * [泛型](generics.md)
     * [Traits](traits.md)
-    * [Drop](drop.md)
+    * [丟棄](drop.md)
     * [if let](if-let.md)
     * [Trait Objects](trait-objects.md)
     * [Closures](closures.md)

src/drop.md

@@ -1,8 +1,7 @@
-% Drop
+% 丟棄
 
-Now that we’ve discussed traits, let’s talk about a particular trait provided
-by the Rust standard library, [`Drop`][drop]. The `Drop` trait provides a way
-to run some code when a value goes out of scope. For example:
+基於我們已經討論過特徵了，現在讓我們一起來了解由Rust語言標準庫提供的特殊的特徵—— [`Drop`(丟棄)][drop]。
+丟棄(drop)的特徵(trait)是由一個值離開作用域時觸發的方法，譬如說：
 
 [drop]: ../std/ops/trait.Drop.html
 
@@ -23,13 +22,11 @@ fn main() {
 } // x goes out of scope here
 ```
 
-When `x` goes out of scope at the end of `main()`, the code for `Drop` will
-run. `Drop` has one method, which is also called `drop()`. It takes a mutable
-reference to `self`.
+當變數 `x` 離開它的作用域 `main()` 的底部的時候, 丟棄 `Drop` 的代碼就被觸發了。
+丟棄 `Drop` 有一個方法也被寫作 `drop()`。它用來回去一個自身 `self` 的可變引用。
 
-That’s it! The mechanics of `Drop` are very simple, but there are some
-subtleties. For example, values are dropped in the opposite order they are
-declared. Here’s another example:
+正因如此，丟棄 `Drop` 的運行原理非常簡單。只是還有一些細節問題：
+譬如說值會被以它們宣告的相反順序觸發丟棄(drop)的過程，譬如說：
 
 ```rust
 struct Firework {
@@ -48,21 +45,20 @@ fn main() {
 }
 ```
 
-This will output:
+輸出結果：
 
 ```text
 BOOM times 100!!!
 BOOM times 1!!!
 ```
 
-The TNT goes off before the firecracker does, because it was declared
-afterwards. Last in, first out.
+由於 TNT 在 firecracker 之後被聲明，所以 TNT 在 firecracker 之前離開作用域。
+
+那麼 `Drop`  有什麼好處呢？通常情況下 `Drop` 被用來清理和 `struct` 關聯得到資源。
+譬如說 [`Arc<T>` 型別][arc] 是一個引用計數型別。
+當 `Drop` 被調用的時候，它就會減少引用計數。
+此外，如果引用的總數為零，底層的值將會被擦除。
 
-So what is `Drop` good for? Generally, `Drop` is used to clean up any resources
-associated with a `struct`. For example, the [`Arc<T>` type][arc] is a
-reference-counted type. When `Drop` is called, it will decrement the reference
-count, and if the total number of references is zero, will clean up the
-underlying value.
 
 [arc]: ../std/sync/struct.Arc.html