Adjust structure

course9/course_en.md

@@ -185,6 +185,18 @@ impl MyTrait for Int with f(self) {
 
 ---
 
+# Automatic Derivation of Builtin Traits
+
+- Some simple builtin traits can be automatically derived by adding `derive(<traits>)` after the type definition.
+
+```moonbit no-check
+struct BoxedInt { value : Int } derive(Default, Eq, Compare, Debug)
+```
+
+- The member data types should have implemented the same traits.
+
+---
+
 # Method Chaining
 
 - In addition to `<type>::<method>(<expr>, ...)`, we can as well call the method using `<expr>.<method>(...)`, given `<expr>` is of type `<type>`.
@@ -207,18 +219,6 @@ fn init {
 
 ---
 
-# Automatic Derivation of Builtin Traits
-
-- Some simple builtin traits can be automatically derived by adding `derive(<traits>)` after the type definition.
-
-```moonbit no-check
-struct BoxedInt { value : Int } derive(Default, Eq, Compare, Debug)
-```
-
-- The member data types should have implemented the same traits.
-
----
-
 # Using Traits to Implement a Map
 
 - A map is a collection of key-value pairs.

course9/lecture_en.md

@@ -154,6 +154,16 @@ impl MyTrait for Int with f(self) {
 }
 ```
 
+### Automatic Derivation
+
+In MoonBit, it is possible to automatically derive certain basic traits by adding `derive(<traits>)` after the type declaration. If the type is composed of other types, those member types must have already implemented the same traits.
+
+In the given example, we derive the `Default`, `Eq`, `Compare`, and `Debug` traits for `BoxedInt`. These traits can be successfully derived because `Int` already implements them. However, if the required traits are not implemented by the member types, the compiler will generate an error message.
+
+```moonbit no-check
+struct BoxedInt { value : Int } derive(Default, Eq, Compare, Debug)
+```
+
 ## Method Chaining
 
 In addition to `<type>::<method>(<expr>, ...)`, we can as well call the method using `<expr>.<method>(...)`, given `<expr>` is of type `<type>`. When defining such methods, `<type>::` can also be omitted when the first parameter is named `self`.
@@ -176,16 +186,6 @@ fn init {
 }
 ```
 
-## Automatic Derivation of Builtin Traits
-
-In MoonBit, it is possible to automatically derive certain basic traits by adding `derive(<traits>)` after the type declaration. If the type is composed of other types, those member types must have already implemented the same traits.
-
-In the given example, we derive the `Default`, `Eq`, `Compare`, and `Debug` traits for `BoxedInt`. These traits can be successfully derived because `Int` already implements them. However, if the required traits are not implemented by the member types, the compiler will generate an error message.
-
-```moonbit no-check
-struct BoxedInt { value : Int } derive(Default, Eq, Compare, Debug)
-```
-
 ## Example: Using Traits to Implement a Map
 
 Now, let's proceed to implement a generic map using traits.