ex(06): move semantics

The first interesting one!

.rustlings-state.txt

···
 DON'T EDIT THIS FILE!
 
-move_semantics1
+structs1
 
 intro1
 intro2
···
 primitive_types5
 primitive_types6
 vecs1
-vecs2
+vecs2
+move_semantics1
+move_semantics2
+move_semantics3
+move_semantics4
+move_semantics5

exercises/06_move_semantics/move_semantics1.rs

···
 // TODO: Fix the compiler error in this function.
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let vec = vec;
+    let mut vec = vec;
 
     vec.push(88);
 

exercises/06_move_semantics/move_semantics2.rs

···
     fn move_semantics2() {
         let vec0 = vec![22, 44, 66];
 
-        let vec1 = fill_vec(vec0);
+        let vec1 = fill_vec(vec0.clone());
 
         assert_eq!(vec0, [22, 44, 66]);
         assert_eq!(vec1, [22, 44, 66, 88]);

exercises/06_move_semantics/move_semantics3.rs

···
 // TODO: Fix the compiler error in the function without adding any new line.
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(mut vec: Vec<i32>) -> Vec<i32> {
     vec.push(88);
 
     vec

exercises/06_move_semantics/move_semantics4.rs

···
     fn move_semantics4() {
         let mut x = Vec::new();
         let y = &mut x;
-        let z = &mut x;
         y.push(42);
+        let z = &mut x;
         z.push(13);
         assert_eq!(x, [42, 13]);
     }

exercises/06_move_semantics/move_semantics5.rs

···
 // removing references (the character `&`).
 
 // Shouldn't take ownership
-fn get_char(data: String) -> char {
+fn get_char(data: &String) -> char {
     data.chars().last().unwrap()
 }
 
 // Should take ownership
-fn string_uppercase(mut data: &String) {
+fn string_uppercase(mut data: String) {
     data = data.to_uppercase();
 
     println!("{data}");
···
 fn main() {
     let data = "Rust is great!".to_string();
 
-    get_char(data);
+    get_char(&data);
 
-    string_uppercase(&data);
+    string_uppercase(data);
 }

solutions/06_move_semantics/move_semantics1.rs

···
+fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+    let mut vec = vec;
+    //  ^^^ added
+
+    vec.push(88);
+
+    vec
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn move_semantics1() {
+        let vec0 = vec![22, 44, 66];
+        let vec1 = fill_vec(vec0);
+        // `vec0` can't be accessed anymore because it is moved to `fill_vec`.
+        assert_eq!(vec1, vec![22, 44, 66, 88]);
+    }
 }

solutions/06_move_semantics/move_semantics2.rs

···
+fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+    let mut vec = vec;
+
+    vec.push(88);
+
+    vec
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn move_semantics2() {
+        let vec0 = vec![22, 44, 66];
+
+        // Cloning `vec0` so that the clone is moved into `fill_vec`, not `vec0`
+        // itself.
+        let vec1 = fill_vec(vec0.clone());
+
+        assert_eq!(vec0, [22, 44, 66]);
+        assert_eq!(vec1, [22, 44, 66, 88]);
+    }
 }

solutions/06_move_semantics/move_semantics3.rs

···
+fn fill_vec(mut vec: Vec<i32>) -> Vec<i32> {
+    //      ^^^ added
+    vec.push(88);
+
+    vec
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn move_semantics3() {
+        let vec0 = vec![22, 44, 66];
+        let vec1 = fill_vec(vec0);
+        assert_eq!(vec1, [22, 44, 66, 88]);
+    }
 }

solutions/06_move_semantics/move_semantics4.rs

···
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    // TODO: Fix the compiler errors only by reordering the lines in the test.
+    // Don't add, change or remove any line.
+    #[test]
+    fn move_semantics4() {
+        let mut x = Vec::new();
+        let y = &mut x;
+        // `y` used here.
+        y.push(42);
+        // The mutable reference `y` is not used anymore,
+        // therefore a new reference can be created.
+        let z = &mut x;
+        z.push(13);
+        assert_eq!(x, [42, 13]);
+    }
 }

solutions/06_move_semantics/move_semantics5.rs

···
+#![allow(clippy::ptr_arg)]
+
+// Borrows instead of taking ownership.
+// It is recommended to use `&str` instead of `&String` here. But this is
+// enough for now because we didn't handle strings yet.
+fn get_char(data: &String) -> char {
+    data.chars().last().unwrap()
+}
+
+// Takes ownership instead of borrowing.
+fn string_uppercase(mut data: String) {
+    data = data.to_uppercase();
+
+    println!("{data}");
+}
+
 fn main() {
-    // DON'T EDIT THIS SOLUTION FILE!
-    // It will be automatically filled after you finish the exercise.
+    let data = "Rust is great!".to_string();
+
+    get_char(&data);
+
+    string_uppercase(data);
 }