Merge 5f2aff6783 into 8d0aa11a35

docs: add gerases as a contributor for content

.all-contributorsrc

@@ -2550,6 +2550,15 @@
       "contributions": [
         "content"
       ]
+    },
+    {
+      "login": "gerases",
+      "name": "gerases",
+      "avatar_url": "https://avatars.githubusercontent.com/u/8953623?v=4",
+      "profile": "https://github.com/gerases",
+      "contributions": [
+        "content"
+      ]
     }
   ],
   "contributorsPerLine": 8,

AUTHORS.md

@@ -360,6 +360,9 @@ authors.
       <td align="center" valign="top" width="12.5%"><a href="https://github.com/neuschaefer"><img src="https://avatars.githubusercontent.com/u/1021512?v=4?s=100" width="100px;" alt="J. Neuschäfer"/><br /><sub><b>J. Neuschäfer</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=neuschaefer" title="Code">💻</a></td>
       <td align="center" valign="top" width="12.5%"><a href="https://scooterhacking.org"><img src="https://avatars.githubusercontent.com/u/58905488?v=4?s=100" width="100px;" alt="Bastian Pedersen"/><br /><sub><b>Bastian Pedersen</b></sub></a><br /><a href="#content-bastianpedersen" title="Content">🖋</a></td>
     </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/gerases"><img src="https://avatars.githubusercontent.com/u/8953623?v=4?s=100" width="100px;" alt="gerases"/><br /><sub><b>gerases</b></sub></a><br /><a href="#content-gerases" title="Content">🖋</a></td>
+    </tr>
   </tbody>
 </table>
 

exercises/02_functions/README.md

@@ -1,8 +1,9 @@
 # Functions
 
 Here, you'll learn how to write functions and how the Rust compiler can help you debug errors even
-in more complex code.
+in more complex code. You will also learn what is the difference with closures.
 
 ## Further information
 
 - [How Functions Work](https://doc.rust-lang.org/book/ch03-03-how-functions-work.html)
+- [Closures](https://doc.rust-lang.org/book/ch13-01-closures.html)

exercises/02_functions/functions6.rs

@@ -0,0 +1,20 @@
+// functions6.rs
+//
+// Here you can practice special functions called `closures`, that can capture
+// variables of their parent context.
+// Fix the code below to make it compile, without changing the two closure
+// definitions.
+//
+// Execute `rustlings hint functions6` or use the `hint` watch subcommand for
+// some hints.
+
+// I AM NOT DONE
+
+fn main() {
+  let closure_1 = |input_var: u32| -> u32 {input_var + outer_var};
+  println!("Closure#1 returns {}", closure_1(5));
+
+  let closure_2 = |input_var| println!("Closure#2 (input_var {})", input_var);
+  closure_2(2);
+  closure_2("5");
+}

exercises/06_move_semantics/move_semantics7.rs

@@ -0,0 +1,27 @@
+// move_semantics6.rs
+//
+// Here you will practice how mutable/immutable borrowing works in the context
+// of a closure.
+//
+// Try to fix this code to make it compile and not panic.
+// You can't change anything except removing 1 line.
+//
+// Execute `rustlings hint move_semantics7` or use the `hint` watch subcommand
+// for a hint.
+
+// I AM NOT DONE
+
+fn main() {
+  let mut counter = 0;
+
+  let mut increment = || {
+    counter += 1;
+    println!("counter: {}", counter);
+  };
+
+  increment();
+  let _reborrowed_counter = &counter;
+  increment();
+
+  assert_eq!(counter, 2);
+}

exercises/11_hashmaps/hashmaps3.rs

@@ -36,7 +36,7 @@ fn build_scores_table(results: String) -> HashMap<String, Team> {
         let team_2_score: u8 = v[3].parse().unwrap();
         // TODO: Populate the scores table with details extracted from the
         // current line. Keep in mind that goals scored by team_1
-        // will be the number of goals conceded from team_2, and similarly
+        // will be the number of goals conceded by team_2, and similarly
         // goals scored by team_2 will be the number of goals conceded by
         // team_1.
     }

exercises/README.md

@@ -3,7 +3,7 @@
 | Exercise               | Book Chapter        |
 | ---------------------- | ------------------- |
 | variables              | §3.1                |
-| functions              | §3.3                |
+| functions              | §3.3, §13.1         |
 | if                     | §3.5                |
 | primitive_types        | §3.2, §4.3          |
 | vecs                   | §8.1                |

info.toml

@@ -164,6 +164,21 @@ They are not the same. There are two solutions:
 1. Add a `return` ahead of `num * num;`
 2. remove `;`, make it to be `num * num`"""
 
+[[exercises]]
+name = "functions6"
+path = "exercises/02_functions/functions6.rs"
+mode = "compile"
+hint = """
+Hint FIX #1: Closures can capture variables defined in the outer context.
+
+Hint FIX #2: Closures can infer both input and returned types, when they are not
+specified in the signature. But the closure cannot be reused with different
+input types.
+
+Read more about closures in the rust book dedicated section:
+https://doc.rust-lang.org/book/ch13-01-closures.html
+"""
+
 # IF
 
 [[exercises]]
@@ -406,6 +421,20 @@ Can you figure out how?
 
 Another hint: it has to do with the `&` character."""
 
+[[exercises]]
+name = "move_semantics7"
+path = "exercises/06_move_semantics/move_semantics7.rs"
+mode = "compile"
+hint = """
+When a closure capture a variable to modify it, it borrows that variable as a
+mutable reference. In this exercise, as the closure mutably borrows `counter`
+and is called later, any attempt to reborrow `counter` in between will lead to
+an error.
+
+You cannot immutably borrow a variable if a mutable closure is
+called later in the scope.
+"""
+
 # STRUCTS
 
 [[exercises]]