tour: add lesson for newtype (#384)

moonbitlang · Dec 25, 2024 · 4530fe3 · 4530fe3
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Showing 6 changed files with 9 additions and 2 deletions.
diff --git a/moonbit-tour/tour/chapter2_data_types/lesson4_newtype/index.mbt b/moonbit-tour/tour/chapter2_data_types/lesson4_newtype/index.mbt
@@ -4,8 +4,9 @@ type UserName String
 fn main {
   let user_id : UserId = UserId(1)
   let user_name : UserName = UserName("Alice")
-  let UserId(id) = user_id
-  let UserName(name) = user_name
   println(user_id._)
   println(user_name._)
+  // use some pattern matching to extract the values
+  let UserId(id) = user_id 
+  let UserName(name) = user_name
 }
diff --git a/moonbit-tour/tour/chapter2_data_types/lesson4_newtype/index.md b/moonbit-tour/tour/chapter2_data_types/lesson4_newtype/index.md
@@ -0,0 +1,6 @@
+# Newtype
+
+Newtypes are similar to enums with only one constructor (with the same name as the newtype itself). You can use the constructor to create values of the newtype and use `._` to extract the internal representation. 
+
+*Pattern matching* can also be used.
+
diff --git a/...pter2_data_types/lesson4_option/index.mbt → ...pter2_data_types/lesson5_option/index.mbt b/...pter2_data_types/lesson4_option/index.mbt → ...pter2_data_types/lesson5_option/index.mbt
diff --git a/...apter2_data_types/lesson4_option/index.md → ...apter2_data_types/lesson5_option/index.md b/...apter2_data_types/lesson4_option/index.md → ...apter2_data_types/lesson5_option/index.md
diff --git a/...pter2_data_types/lesson5_result/index.mbt → ...pter2_data_types/lesson6_result/index.mbt b/...pter2_data_types/lesson5_result/index.mbt → ...pter2_data_types/lesson6_result/index.mbt
diff --git a/...apter2_data_types/lesson5_result/index.md → ...apter2_data_types/lesson6_result/index.md b/...apter2_data_types/lesson5_result/index.md → ...apter2_data_types/lesson6_result/index.md