chore: bump version

feat: add rc1.rs exercise

.all-contributorsrc

@@ -1146,6 +1146,357 @@
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.clog.toml

@@ -1,4 +0,0 @@
-[clog]
-
-repository = "https://github.com/rust-lang/rustlings"
-changelog = "CHANGELOG.md"

.editorconfig

@@ -2,6 +2,6 @@ root = true
 
 [*.rs]
 end_of_line = lf
-insert_final_newfile = true
+insert_final_newline = true
 indent_style = space
 indent_size = 4

.github/workflows/rust.yml

@@ -0,0 +1,20 @@
+name: Rustlings Tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Build
+      run: cargo build --verbose
+    - name: Run tests
+      run: cargo test --verbose

.gitignore

@@ -5,6 +5,8 @@ target/
 *.pdb
 exercises/clippy/Cargo.toml
 exercises/clippy/Cargo.lock
+rust-project.json
 .idea
 .vscode
 *.iml
+*.o

.gitpod.yml

@@ -4,4 +4,4 @@ tasks:
 
 vscode:
   extensions:
-    - rust-lang.rust@0.7.8:CvNqMTgDdt3UXt+6BCDTVg==
+    - rust-lang.rust@0.7.8

AUTHORS.md

@@ -164,6 +164,55 @@ authors.
     <td align="center"><a href="https://github.com/ragreenburg"><img src="https://avatars.githubusercontent.com/u/24358100?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ragreenburg</b></sub></a><br /><a href="#content-ragreenburg" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/stevenfukase"><img src="https://avatars.githubusercontent.com/u/66785624?v=4?s=100" width="100px;" alt=""/><br /><sub><b>stevenfukase</b></sub></a><br /><a href="#content-stevenfukase" title="Content">🖋</a></td>
     <td align="center"><a href="https://github.com/J-S-Kim"><img src="https://avatars.githubusercontent.com/u/17569303?v=4?s=100" width="100px;" alt=""/><br /><sub><b>J-S-Kim</b></sub></a><br /><a href="#content-J-S-Kim" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/Fointard"><img src="https://avatars.githubusercontent.com/u/9333398?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fointard</b></sub></a><br /><a href="#content-Fointard" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/rytheo"><img src="https://avatars.githubusercontent.com/u/22184325?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ryan Lowe</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=rytheo" title="Code">💻</a></td>
+    <td align="center"><a href="http://www.dashen.tech"><img src="https://avatars.githubusercontent.com/u/15921519?v=4?s=100" width="100px;" alt=""/><br /><sub><b>cui fliter</b></sub></a><br /><a href="#content-cuishuang" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/luskwater"><img src="https://avatars.githubusercontent.com/u/42529?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ron Lusk</b></sub></a><br /><a href="#content-luskwater" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="http://liby.github.io/liby/"><img src="https://avatars.githubusercontent.com/u/38807139?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Bryan Lee</b></sub></a><br /><a href="#content-liby" title="Content">🖋</a></td>
+    <td align="center"><a href="http://nandaja.space"><img src="https://avatars.githubusercontent.com/u/2624550?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Nandaja Varma</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nandajavarma" title="Documentation">📖</a></td>
+    <td align="center"><a href="https://github.com/merelymyself"><img src="https://avatars.githubusercontent.com/u/88221256?v=4?s=100" width="100px;" alt=""/><br /><sub><b>pwygab</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=merelymyself" title="Code">💻</a></td>
+    <td align="center"><a href="http://linkedin.com/in/lucasgrvarela"><img src="https://avatars.githubusercontent.com/u/37870368?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Lucas Grigolon Varela</b></sub></a><br /><a href="#content-lucasgrvarela" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/bufo24"><img src="https://avatars.githubusercontent.com/u/32884105?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Bufo</b></sub></a><br /><a href="#content-bufo24" title="Content">🖋</a></td>
+    <td align="center"><a href="http://rustnote.com"><img src="https://avatars.githubusercontent.com/u/77730378?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jack Clayton</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jackos" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/klkl0808"><img src="https://avatars.githubusercontent.com/u/24694249?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Konstantin</b></sub></a><br /><a href="#content-klkl0808" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/0pling"><img src="https://avatars.githubusercontent.com/u/104090344?v=4?s=100" width="100px;" alt=""/><br /><sub><b>0pling</b></sub></a><br /><a href="#content-0pling" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/KatanaFluorescent"><img src="https://avatars.githubusercontent.com/u/60199077?v=4?s=100" width="100px;" alt=""/><br /><sub><b>KatanaFluorescent</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=KatanaFluorescent" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/Drew-Morris"><img src="https://avatars.githubusercontent.com/u/95818166?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Drew Morris</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Drew-Morris" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/camperdue42"><img src="https://avatars.githubusercontent.com/u/43047763?v=4?s=100" width="100px;" alt=""/><br /><sub><b>camperdue42</b></sub></a><br /><a href="#content-camperdue42" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/YsuOS"><img src="https://avatars.githubusercontent.com/u/30138661?v=4?s=100" width="100px;" alt=""/><br /><sub><b>YsuOS</b></sub></a><br /><a href="#content-YsuOS" title="Content">🖋</a></td>
+    <td align="center"><a href="https://lichess.org/@/StevenEmily"><img src="https://avatars.githubusercontent.com/u/58114641?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Steven Nguyen</b></sub></a><br /><a href="#content-icecream17" title="Content">🖋</a></td>
+    <td align="center"><a href="https://noahcairns.dev"><img src="https://avatars.githubusercontent.com/u/94420090?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nacairns1</b></sub></a><br /><a href="#content-nacairns1" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/pgjbz"><img src="https://avatars.githubusercontent.com/u/22059237?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Paulo Gabriel Justino Bezerra</b></sub></a><br /><a href="#content-pgjbz" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/jaystile"><img src="https://avatars.githubusercontent.com/u/46078028?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jason</b></sub></a><br /><a href="#content-jaystile" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="https://exdx.github.io"><img src="https://avatars.githubusercontent.com/u/31546601?v=4?s=100" width="100px;" alt=""/><br /><sub><b>exdx</b></sub></a><br /><a href="#content-exdx" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/Jzow"><img src="https://avatars.githubusercontent.com/u/68860495?v=4?s=100" width="100px;" alt=""/><br /><sub><b>James Zow</b></sub></a><br /><a href="#content-Jzow" title="Content">🖋</a></td>
+    <td align="center"><a href="https://jamesabromley.wordpress.com/"><img src="https://avatars.githubusercontent.com/u/2474334?v=4?s=100" width="100px;" alt=""/><br /><sub><b>James Bromley</b></sub></a><br /><a href="#content-jayber" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/swhiteCQC"><img src="https://avatars.githubusercontent.com/u/77438466?v=4?s=100" width="100px;" alt=""/><br /><sub><b>swhiteCQC</b></sub></a><br /><a href="#content-swhiteCQC" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/neilpate"><img src="https://avatars.githubusercontent.com/u/7802334?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Neil Pate</b></sub></a><br /><a href="#content-neilpate" title="Content">🖋</a></td>
+    <td align="center"><a href="https://wojexe.com"><img src="https://avatars.githubusercontent.com/u/21208490?v=4?s=100" width="100px;" alt=""/><br /><sub><b>wojexe</b></sub></a><br /><a href="#content-wojexe" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/Tostapunk"><img src="https://avatars.githubusercontent.com/u/25140297?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mattia Schiavon</b></sub></a><br /><a href="#content-Tostapunk" title="Content">🖋</a></td>
+    <td align="center"><a href="http://toucantoco.com"><img src="https://avatars.githubusercontent.com/u/18406791?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Eric Jolibois</b></sub></a><br /><a href="#content-PrettyWood" title="Content">🖋</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="http://edwinchang.vercel.app"><img src="https://avatars.githubusercontent.com/u/88263098?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Edwin Chang</b></sub></a><br /><a href="#content-EdwinChang24" title="Content">🖋</a></td>
+    <td align="center"><a href="https://saikat.dev/"><img src="https://avatars.githubusercontent.com/u/7412443?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Saikat Das</b></sub></a><br /><a href="#content-saikatdas0790" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/thatlittleboy"><img src="https://avatars.githubusercontent.com/u/30731072?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jeremy Goh</b></sub></a><br /><a href="#content-thatlittleboy" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/Lioness100"><img src="https://avatars.githubusercontent.com/u/65814829?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Lioness100</b></sub></a><br /><a href="#content-Lioness100" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/tvkn"><img src="https://avatars.githubusercontent.com/u/79277926?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Tristan Nicholls</b></sub></a><br /><a href="#content-tvkn" title="Content">🖋</a></td>
+    <td align="center"><a href="http://clairewang.net"><img src="https://avatars.githubusercontent.com/u/9344258?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Claire</b></sub></a><br /><a href="#content-clairew" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/Mouwrice"><img src="https://avatars.githubusercontent.com/u/56763273?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Maurice Van Wassenhove</b></sub></a><br /><a href="#content-Mouwrice" title="Content">🖋</a></td>
+    <td align="center"><a href="http://jmthree.com"><img src="https://avatars.githubusercontent.com/u/77524?v=4?s=100" width="100px;" alt=""/><br /><sub><b>John Mendelewski</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=johnmendel" title="Code">💻</a></td>
+  </tr>
+  <tr>
+    <td align="center"><a href="http://fakhoury.xyz"><img src="https://avatars.githubusercontent.com/u/20828724?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brian Fakhoury</b></sub></a><br /><a href="#content-brianfakhoury" title="Content">🖋</a></td>
+    <td align="center"><a href="https://github.com/markusboehme"><img src="https://avatars.githubusercontent.com/u/5074759?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Markus Boehme</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=markusboehme" title="Code">💻</a></td>
+    <td align="center"><a href="https://github.com/nico-vromans"><img src="https://avatars.githubusercontent.com/u/48183857?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Nico Vromans</b></sub></a><br /><a href="#content-nico-vromans" title="Content">🖋</a></td>
   </tr>
 </table>
 

CHANGELOG.md

@@ -1,3 +1,153 @@
+<a name="5.1.0"></a>
+## 5.1.0 (2022-08-16)
+
+#### Features
+
+- Added a new `rc1` exercise.
+- Added a new `cow1` exercise.
+
+#### Bug Fixes
+
+- **variables5**: Corrected reference to previous exercise
+- **functions4**: Fixed line number reference
+- **strings3**: Clarified comment wording
+- **traits4, traits5**: Fixed line number reference
+- **traits5**:
+  - Fixed typo in "parameter"
+  - Made exercise prefer a traits-based solution
+- **lifetimes2**: Improved hint
+- **threads3**: Fixed typo in hint
+- **box1**: Replaced `unimplemented!` with `todo!`
+- **errors5**: Provided an explanation for usage of `Box<dyn Error>`
+- **quiz2**: Fixed a typo
+- **macros**: Updated the macros book link
+- **options1**:
+  - Removed unused code
+  - Added more granular tests
+- Fixed some comment syntax shenanigans in info.toml
+
+#### Housekeeping
+
+- Fixed a typo in .editorconfig
+- Fixed a typo in integration_tests.rs
+- Clarified manual installation instructions using `cargo install --path .`
+- Added a link to our Zulip in the readme file
+
+<a name="5.0.0"></a>
+## 5.0.0 (2022-07-16)
+
+#### Features
+
+- Hint comments in exercises now also include a reference to the
+  `hint` watch mode subcommand.
+- **intro1**: Added more hints to point the user to the source file.
+- **variables**: Switched variables3 and variables4.
+- Moved `vec` and `primitive_types` exercises before `move_semantics`.
+- Renamed `vec` to `vecs` to be more in line with the naming in general.
+- Split up the `collections` exercises in their own folders.
+- **vec2**: Added a second part of the function that provides an alternative,
+  immutable way of modifying vec values.
+- **enums3**: Added a hint.
+- Moved `strings` before `modules`.
+- Added a `strings3` exercise to teach modifying strings.
+- Added a `hashmaps3` exercise for some advanced usage of hashmaps.
+- Moved the original `quiz2` to be `strings4`, since it only tested strings
+  anyways.
+- Reworked `quiz2` into a new exercise that tests more chapters.
+- Renamed `option` to `options`.
+- **options1**: Rewrote parts of the exercise to remove the weird array
+  iteration stuff.
+- Moved `generics3` to be `quiz3`.
+- Moved box/arc exercises behind `iterators`.
+- **iterators4**: Added a test for factorials of zero.
+- Split `threads1` between two exercises, the first one focusing more on
+  `JoinHandle`s.
+- Added a `threads3` exercises that uses `std::sync::mpsc`.
+- Added a `clippy3` exercises with some more interesting checks.
+- **as_ref_mut**: Added a section that actually tests `AsMut`.
+- Added 3 new lifetimes exercises.
+- Added 3 new traits exercises.
+
+#### Bug Fixes
+
+- **variables2**: Made output messages more verbose.
+- **variables5**: Added a nudging hint about shadowing.
+- **variables6**: Fixed link to book.
+- **functions**: Clarified the README wording. Generally cleaned up
+  some hints and added some extra comments.
+- **if2**: Renamed function name to `foo_if_fizz`.
+- **move_semantics**: Clarified some hints.
+- **quiz1**: Renamed the function name to be more verbose.
+- **structs1**: Use an integer type instead of strings. Renamed "unit structs"
+  to "unit-like structs", as is used in the book.
+- **structs3**: Added the `panic!` statement in from the beginning.
+- **errors1**: Use `is_empty()` instead of `len() > 0`
+- **errors3**: Improved the hint.
+- **errors5**: Improved exercise instructions and the hint.
+- **errors6**: Provided the skeleton of one of the functions that's supposed
+  to be implemented.
+- **iterators3**: Inserted `todo!` into `divide()` to keep a compiler error
+  from happening.
+- **from_str**: Added a hint comment about string error message conversion with
+  `Box<dyn Error>`.
+- **try_from_into**: Fixed the function name in comment.
+  
+#### Removed
+
+- Removed the legacy LSP feature that was using `mod.rs` files.
+- Removed `quiz4`.
+- Removed `advanced_errs`. These were the last exercises in the recommended
+  order, and I've always felt like they didn't quite fit in with the mostly
+  simple, book-following style we've had in Rustlings.
+
+#### Housekeeping
+
+- Added missing exercises to the book index.
+- Updated spacing in Cargo.toml.
+- Added a GitHub actions config so that tests run on every PR/commit.
+
+<a name="4.8.0"></a>
+## 4.8.0 (2022-07-01)
+
+#### Features
+
+- Added a progress indicator for `rustlings watch`.
+- The installation script now checks for Rustup being installed.
+- Added a `rustlings lsp` command to enable `rust-analyzer`.
+
+#### Bug Fixes
+
+- **move_semantics5**: Replaced "in vogue" with "in scope" in hint.
+- **if2**: Fixed a typo in the hint.
+- **variables1**: Fixed an incorrect line reference in the hint.
+- Fixed an out of bounds check in the installation Bash script.
+
+#### Housekeeping
+
+- Replaced the git.io URL with the fully qualified URL because of git.io's sunsetting.
+- Removed the deprecated Rust GitPod extension.
+
+<a name="4.7.1"></a>
+## 4.7.1 (2022-04-20)
+
+#### Features
+
+- The amount of dependency crates that need to be compiled went down from ~65 to
+  ~45 by bumping dependency versions.
+- The minimum Rust version in the install scripts has been bumped to 1.56.0 (this isn't in
+  the release itself, since install scripts don't really get versioned)
+
+#### Bug Fixes
+
+- **arc1**: A small part has been rewritten using a more functional code style (#968).
+- **using_as**: A small part has been refactored to use `sum` instead of `fold`, resulting
+  in better readability.
+
+#### Housekeeping
+
+- The changelog will now be manually written instead of being automatically generated by the
+  Git log.
+
 <a name="4.7.0"></a>
 ## 4.7.0 (2022-04-14)
 
@@ -264,7 +414,7 @@
 #### Features
 
 *   add Option2 exercise (#290) ([86b5c08b](https://github.com/rust-lang/rustlings/commit/86b5c08b9bea1576127a7c5f599f5752072c087d))
-*   add excercise for option (#282) ([135e5d47](https://github.com/rust-lang/rustlings/commit/135e5d47a7c395aece6f6022117fb20c82f2d3d4))
+*   add exercise for option (#282) ([135e5d47](https://github.com/rust-lang/rustlings/commit/135e5d47a7c395aece6f6022117fb20c82f2d3d4))
 *   add new exercises for generics (#280) ([76be5e4e](https://github.com/rust-lang/rustlings/commit/76be5e4e991160f5fd9093f03ee2ba260e8f7229))
 * **ci:**  add buildkite config ([b049fa2c](https://github.com/rust-lang/rustlings/commit/b049fa2c84dba0f0c8906ac44e28fd45fba51a71))
 

CONTRIBUTING.md

@@ -21,7 +21,7 @@ _implement a new feature! ➡️ [open an Issue to discuss it first, then a Pull
 
 `rustlings` is basically a glorified `rustc` wrapper. Therefore the source code
 isn't really that complicated since the bulk of the work is done by `rustc`.
-`src/main.rs` contains a simple `clap` CLI that loads from `src/verify.rs` and `src/run.rs`.
+`src/main.rs` contains a simple `argh` CLI that connects to most of the other source files.
 
 <a name="addex"></a>
 ### Adding an exercise
@@ -29,7 +29,7 @@ isn't really that complicated since the bulk of the work is done by `rustc`.
 The first step is to add the exercise! Name the file `exercises/yourTopic/yourTopicN.rs`, make sure to
 put in some helpful links, and link to sections of the book in `exercises/yourTopic/README.md`.
 
-Next make sure it runs with `rustlings`. The exercise metadata is stored in `info.toml`, under the `exercises` array. The order of the `exercises` array determines the order the exercises are run by `rustlings verify`.
+Next make sure it runs with `rustlings`. The exercise metadata is stored in `info.toml`, under the `exercises` array. The order of the `exercises` array determines the order the exercises are run by `rustlings verify` and `rustlings watch`.
 
 Add the metadata for your exercise in the correct order in the `exercises` array. If you are unsure of the correct ordering, add it at the bottom and ask in your pull request. The exercise metadata should contain the following:
 ```diff
@@ -43,7 +43,7 @@ Add the metadata for your exercise in the correct order in the `exercises` array
   ...
 ```
 
-The `mode` attribute decides whether Rustlings will only compile your exercise, or compile and test it. If you have tests to verify in your exercise, choose `test`, otherwise `compile`.
+The `mode` attribute decides whether Rustlings will only compile your exercise, or compile and test it. If you have tests to verify in your exercise, choose `test`, otherwise `compile`. If you're working on a Clippy exercise, use `mode = "clippy"`.
 
 That's all! Feel free to put up a pull request.
 
@@ -67,19 +67,19 @@ changes. There's a couple of things to watch out for:
 #### Write correct commit messages
 
 We follow the [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0-beta.4/)
-specification, because it makes it easier to generate changelogs automatically.
+specification.
 This means that you have to format your commit messages in a specific way. Say
 you're working on adding a new exercise called `foobar1.rs`. You could write
 the following commit message:
 
 ```
-feat: Add foobar1.rs exercise
+feat: add foobar1.rs exercise
 ```
 
 If you're just fixing a bug, please use the `fix` type:
 
 ```
-fix(verify): Make sure verify doesn't self-destruct
+fix(verify): make sure verify doesn't self-destruct
 ```
 
 The scope within the brackets is optional, but should be any of these:
@@ -96,7 +96,7 @@ When the commit also happens to close an existing issue, link it in the message
 body:
 
 ```
-fix: Update foobar
+fix: update foobar
 
 closes #101029908
 ```
@@ -104,13 +104,13 @@ closes #101029908
 If you're doing simple changes, like updating a book link, use `chore`:
 
 ```
-chore: Update exercise1.rs book link
+chore: update exercise1.rs book link
 ```
 
 If you're updating documentation, use `docs`:
 
 ```
-docs: Add more information to Readme
+docs: add more information to Readme
 ```
 
 If, and only if, you're absolutely sure you want to make a breaking change
@@ -118,7 +118,7 @@ If, and only if, you're absolutely sure you want to make a breaking change
 explain the breaking change in the message body:
 
 ```
-fix!: Completely change verification
+fix!: completely change verification
 
 BREAKING CHANGE: This has to be done because lorem ipsum dolor
 ```
@@ -126,6 +126,5 @@ BREAKING CHANGE: This has to be done because lorem ipsum dolor
 #### Pull Request Workflow
 
 Once you open a Pull Request, it may be reviewed or labeled (or both) until
-the maintainers accept your change. Then, [bors](https://github.com/bors) will
-run the test suite with your changes and if it's successful, automatically
-merge it in!
+the maintainers accept your change. Please be patient, it may take some time
+for this to happen!

Cargo.lock

@@ -52,17 +52,6 @@ dependencies = [
  "predicates-tree",
 ]
 
-[[package]]
-name = "atty"
-version = "0.2.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
-dependencies = [
- "hermit-abi",
- "libc",
- "winapi 0.3.9",
-]
-
 [[package]]
 name = "autocfg"
 version = "1.0.1"
@@ -87,45 +76,15 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
-[[package]]
-name = "clicolors-control"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90082ee5dcdd64dc4e9e0d37fbf3ee325419e39c0092191e0393df65518f741e"
-dependencies = [
- "atty",
- "lazy_static",
- "libc",
- "winapi 0.3.9",
-]
-
 [[package]]
 name = "console"
-version = "0.7.7"
+version = "0.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ca57c2c14b8a2bf3105bc9d15574aad80babf6a9c44b1058034cdf8bd169628"
-dependencies = [
- "atty",
- "clicolors-control",
- "encode_unicode",
- "lazy_static",
- "libc",
- "parking_lot",
- "regex",
- "termios",
- "unicode-width",
- "winapi 0.3.9",
-]
-
-[[package]]
-name = "console"
-version = "0.14.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3993e6445baa160675931ec041a5e03ca84b9c6e32a056150d3aa2bdda0a1f45"
+checksum = "a28b32d32ca44b70c3e4acd7db1babf555fa026e385fb95f18028f88848b3c31"
 dependencies = [
  "encode_unicode",
- "lazy_static",
  "libc",
+ "once_cell",
  "regex",
  "terminal_size",
  "unicode-width",
@@ -228,24 +187,23 @@ dependencies = [
 ]
 
 [[package]]
-name = "hermit-abi"
-version = "0.1.19"
+name = "home"
+version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+checksum = "2456aef2e6b6a9784192ae780c0f15bc57df0e918585282325e8c8ac27737654"
 dependencies = [
- "libc",
+ "winapi 0.3.9",
 ]
 
 [[package]]
 name = "indicatif"
-version = "0.10.3"
+version = "0.16.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "40ecd1e2ee08e6c255ce890f5a99d17000850e664e7acf119fb03b25b0575bfe"
+checksum = "2d207dc617c7a380ab07ff572a6e52fa202a2a8f355860ac9c38e23f8196be1b"
 dependencies = [
- "console 0.14.1",
+ "console",
  "lazy_static",
  "number_prefix",
- "parking_lot",
  "regex",
 ]
 
@@ -269,15 +227,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "instant"
-version = "0.1.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bee0328b1209d157ef001c94dd85b4f8f64139adb0eac2659f4b08382b2f474d"
-dependencies = [
- "cfg-if 1.0.0",
-]
-
 [[package]]
 name = "iovec"
 version = "0.1.4"
@@ -289,9 +238,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "0.4.8"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b71991ff56294aa922b450139ee08b3bfc70982c6b2c7562771375cf73542dd4"
+checksum = "112c678d4050afce233f4f2852bb2eb519230b3cf12f33585275537d7e41578d"
 
 [[package]]
 name = "kernel32-sys"
@@ -321,15 +270,6 @@ version = "0.2.100"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1fa8cddc8fbbee11227ef194b5317ed014b8acbf15139bd716a18ad3fe99ec5"
 
-[[package]]
-name = "lock_api"
-version = "0.4.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0382880606dff6d15c9476c416d18690b72742aa7b605bb6dd6ec9030fbf07eb"
-dependencies = [
- "scopeguard",
-]
-
 [[package]]
 name = "log"
 version = "0.4.14"
@@ -434,37 +374,15 @@ dependencies = [
 
 [[package]]
 name = "number_prefix"
-version = "0.2.8"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dbf9993e59c894e3c08aa1c2712914e9e6bf1fcbfc6bef283e2183df345a4fee"
-dependencies = [
- "num-traits",
-]
+checksum = "830b246a0e5f20af87141b25c173cd1b609bd7779a4617d6ec582abaf90870f3"
 
 [[package]]
-name = "parking_lot"
-version = "0.11.1"
+name = "once_cell"
+version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d7744ac029df22dca6284efe4e898991d28e3085c706c972bcd7da4a27a15eb"
-dependencies = [
- "instant",
- "lock_api",
- "parking_lot_core",
-]
-
-[[package]]
-name = "parking_lot_core"
-version = "0.8.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fa7a782938e745763fe6907fc6ba86946d72f49fe7e21de074e08128a99fb018"
-dependencies = [
- "cfg-if 1.0.0",
- "instant",
- "libc",
- "redox_syscall",
- "smallvec",
- "winapi 0.3.9",
-]
+checksum = "87f3e037eac156d1775da914196f0f37741a274155e34a0b7e427c35d2a2ecb9"
 
 [[package]]
 name = "predicates"
@@ -524,9 +442,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.5.4"
+version = "1.5.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
+checksum = "1a11647b6b25ff05a515cb92c365cec08801e83423a235b51e231e1808747286"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -541,17 +459,19 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "rustlings"
-version = "4.7.0"
+version = "5.1.0"
 dependencies = [
  "argh",
  "assert_cmd",
- "console 0.7.7",
+ "console",
  "glob",
+ "home",
  "indicatif",
  "notify",
  "predicates",
  "regex",
  "serde",
+ "serde_json",
  "toml",
 ]
 
@@ -570,12 +490,6 @@ dependencies = [
  "winapi-util",
 ]
 
-[[package]]
-name = "scopeguard"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
-
 [[package]]
 name = "serde"
 version = "1.0.129"
@@ -598,9 +512,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.66"
+version = "1.0.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "336b10da19a12ad094b59d870ebde26a45402e5b470add4b5fd03c5048a32127"
+checksum = "9b7ce2b32a1aed03c558dc61a5cd328f15aff2dbc17daad8fb8af04d2100e15c"
 dependencies = [
  "itoa",
  "ryu",
@@ -613,12 +527,6 @@ version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c307a32c1c5c437f38c7fd45d753050587732ba8628319fbdf12a7e289ccc590"
 
-[[package]]
-name = "smallvec"
-version = "1.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
-
 [[package]]
 name = "syn"
 version = "1.0.75"
@@ -640,20 +548,11 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
-[[package]]
-name = "termios"
-version = "0.3.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "411c5bf740737c7918b8b1fe232dca4dc9f8e754b8ad5e20966814001ed0ac6b"
-dependencies = [
- "libc",
-]
-
 [[package]]
 name = "toml"
-version = "0.4.10"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "758664fc71a3a69038656bee8b6be6477d2a6c315a6b81f7081f591bffa4111f"
+checksum = "8d82e1a7758622a465f8cee077614c73484dac5b836c02ff6a40d5d1010324d7"
 dependencies = [
  "serde",
 ]

Cargo.toml

@@ -1,17 +1,20 @@
 [package]
 name = "rustlings"
-version = "4.7.0"
-authors = ["mokou <mokou@fastmail.com>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
+version = "5.1.0"
+authors = ["Liv <mokou@fastmail.com>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
 edition = "2021"
 
 [dependencies]
-argh = "0.1.4"
-indicatif = "0.10.3"
-console = "0.7.7"
-notify = "4.0.15"
-toml = "0.4.10"
-regex = "1.1.6"
-serde = { version = "1.0.10", features = ["derive"] }
+argh = "0.1"
+indicatif = "0.16"
+console = "0.15"
+notify = "4.0"
+toml = "0.5"
+regex = "1.5"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0.81"
+home = "0.5.3"
+glob = "0.3.0"
 
 [[bin]]
 name = "rustlings"
@@ -21,6 +24,3 @@ path = "src/main.rs"
 assert_cmd = "0.11.0"
 predicates = "1.0.1"
 glob = "0.3.0"
-
-[features]
-exercises = []

README.md

@@ -21,9 +21,9 @@ You will need to have Rust installed. You can get it by visiting https://rustup.
 Just run:
 
 ```bash
-curl -L https://git.io/install-rustlings | bash
+curl -L https://raw.githubusercontent.com/rust-lang/rustlings/main/install.sh | bash
 # Or if you want it to be installed to a different path:
-curl -L https://git.io/install-rustlings | bash -s mypath/
+curl -L https://raw.githubusercontent.com/rust-lang/rustlings/main/install.sh | bash -s mypath/
 ```
 
 This will install Rustlings and give you access to the `rustlings` command. Run it to get started!
@@ -39,26 +39,26 @@ Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
 Then, you can run:
 
 ```ps1
-Start-BitsTransfer -Source https://git.io/JTL5v -Destination $env:TMP/install_rustlings.ps1; Unblock-File $env:TMP/install_rustlings.ps1; Invoke-Expression $env:TMP/install_rustlings.ps1
+Start-BitsTransfer -Source https://raw.githubusercontent.com/rust-lang/rustlings/main/install.ps1 -Destination $env:TMP/install_rustlings.ps1; Unblock-File $env:TMP/install_rustlings.ps1; Invoke-Expression $env:TMP/install_rustlings.ps1
 ```
 
 To install Rustlings. Same as on MacOS/Linux, you will have access to the `rustlings` command after it.
 
-When you get a permission denied message then you have to exclude the directory where you placed the rustlings in your virus-scanner
+If you get a permission denied message, you might have to exclude the directory where you cloned Rustlings in your antivirus.
 
-## Browser:
+## Browser
 
 [Run on Repl.it](https://repl.it/github/rust-lang/rustlings)
 
-[Open in Gitpod](https://gitpod.io/#https://github.com/rust-lang/rustlings)
+[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/rust-lang/rustlings)
 
 ## Manually
 
-Basically: Clone the repository at the latest tag, run `cargo install`.
+Basically: Clone the repository at the latest tag, run `cargo install --path .`.
 
 ```bash
-# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 4.6.0)
-git clone -b 4.6.0 --depth 1 https://github.com/rust-lang/rustlings
+# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 5.1.0)
+git clone -b 5.1.0 --depth 1 https://github.com/rust-lang/rustlings
 cd rustlings
 cargo install --force --path .
 ```
@@ -126,24 +126,7 @@ After every couple of sections, there will be a quiz that'll test your knowledge
 
 ## Enabling `rust-analyzer`
 
-`rust-analyzer` support is provided, but it depends on your editor
-whether it's enabled by default. (RLS support is not provided)
-
-To enable `rust-analyzer`, you'll need to make Cargo build the project
-with the `exercises` feature, which will automatically include the `exercises/`
-subfolder in the project. The easiest way to do this is to tell your editor to
-build the project with all features (the equivalent of `cargo build --all-features`).
-For specific editor instructions:
-
-- **VSCode**: Add a `.vscode/settings.json` file with the following:
-```json
-{
-    "rust-analyzer.cargo.features": ["exercises"]
-}
-```
-- **IntelliJ-based Editors**: Using the Rust plugin, everything should work
-    by default.
-- _Missing your editor? Feel free to contribute more instructions!_
+Run the command `rustlings lsp` which will generate a `rust-project.json` at the root of the project, this allows [rust-analyzer](https://rust-analyzer.github.io/) to parse each exercise. 
 
 ## Continuing On
 
@@ -167,28 +150,14 @@ cargo uninstall rustlings
 
 Now you should be done!
 
-## Completion
-
-Rustlings isn't done; there are a couple of sections that are very experimental and don't have proper documentation. These include:
-
-- Errors (`exercises/errors/`)
-- Option (`exercises/option/`)
-- Result (`exercises/result/`)
-- Move Semantics (could still be improved, `exercises/move_semantics/`)
-
-Additionally, we could use exercises on a couple of topics:
-
-- Structs
-- Better ownership stuff
-- `impl`
-- ??? probably more
-
-If you are interested in improving or adding new ones, please feel free to contribute! Read on for more information :)
-
 ## Contributing
 
 See [CONTRIBUTING.md](./CONTRIBUTING.md).
 
+Development-focused discussion about Rustlings happens in the [**rustlings** stream](https://rust-lang.zulipchat.com/#narrow/stream/334454-rustlings)
+on the [Rust Project Zulip](https://rust-lang.zulipchat.com). Feel free to start a new thread there
+if you have ideas or suggestions!
+
 ## Contributors ✨
 
 Thanks goes to the wonderful people listed in [AUTHORS.md](./AUTHORS.md) 🎉

exercises/README.md

@@ -1,24 +1,26 @@
 # Exercise to Book Chapter mapping
 
-| Exercise               | Book Chapter |
-|------------------------|--------------|
-| variables              | §3.1          |
-| functions              | §3.3          |
-| if                     | §3.5          |
-| move_semantics         | §4.1          |
-| primitive_types        | §4.3          |
-| structs                | §5.1          |
-| enums                  | §6            |
-| modules                | §7            |
-| collections            | §8.1, §8.3    |
-| strings                | §8.2          |
-| error_handling         | §9            |
-| generics               | §10           |
-| option                 | §10.1         |
-| traits                 | §10.2         |
-| tests                  | §11.1         |
-| standard_library_types | §13.2         |
-| threads                | §16.1         |
-| macros                 | §19.6         |
-| clippy                 | n/a           |
-| conversions            | n/a           |
+| Exercise               | Book Chapter        |
+| ---------------------- | ------------------- |
+| variables              | §3.1                |
+| functions              | §3.3                |
+| if                     | §3.5                |
+| primitive_types        | §3.2, §4.3          |
+| vecs                   | §8.1                |
+| move_semantics         | §4.1, §4.2          |
+| structs                | §5.1, §5.3          |
+| enums                  | §6, §18.3           |
+| strings                | §8.2                |
+| modules                | §7                  |
+| hashmaps               | §8.3                |
+| options                | §10.1               |
+| error_handling         | §9                  |
+| generics               | §10                 |
+| traits                 | §10.2               |
+| tests                  | §11.1               |
+| lifetimes              | §10.3               |
+| standard_library_types | §13.2, §15.1, §16.3 |
+| threads                | §16.1, §16.2, §16.3 |
+| macros                 | §19.6               |
+| clippy                 | n/a                 |
+| conversions            | n/a                 |

exercises/advanced_errors/advanced_errs1.rs

@@ -1,98 +0,0 @@
-// advanced_errs1.rs
-
-// Remember back in errors6, we had multiple mapping functions so that we
-// could translate lower-level errors into our custom error type using
-// `map_err()`? What if we could use the `?` operator directly instead?
-
-// Make this code compile! Execute `rustlings hint advanced_errs1` for
-// hints :)
-
-// I AM NOT DONE
-
-use std::num::ParseIntError;
-use std::str::FromStr;
-
-// This is a custom error type that we will be using in the `FromStr`
-// implementation.
-#[derive(PartialEq, Debug)]
-enum ParsePosNonzeroError {
-    Creation(CreationError),
-    ParseInt(ParseIntError),
-}
-
-impl From<CreationError> for ParsePosNonzeroError {
-    fn from(e: CreationError) -> Self {
-        // TODO: complete this implementation so that the `?` operator will
-        // work for `CreationError`
-    }
-}
-
-// TODO: implement another instance of the `From` trait here so that the
-// `?` operator will work in the other place in the `FromStr`
-// implementation below.
-
-// Don't change anything below this line.
-
-impl FromStr for PositiveNonzeroInteger {
-    type Err = ParsePosNonzeroError;
-    fn from_str(s: &str) -> Result<PositiveNonzeroInteger, Self::Err> {
-        let x: i64 = s.parse()?;
-        Ok(PositiveNonzeroInteger::new(x)?)
-    }
-}
-
-#[derive(PartialEq, Debug)]
-struct PositiveNonzeroInteger(u64);
-
-#[derive(PartialEq, Debug)]
-enum CreationError {
-    Negative,
-    Zero,
-}
-
-impl PositiveNonzeroInteger {
-    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
-        match value {
-            x if x < 0 => Err(CreationError::Negative),
-            x if x == 0 => Err(CreationError::Zero),
-            x => Ok(PositiveNonzeroInteger(x as u64)),
-        }
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    fn test_parse_error() {
-        // We can't construct a ParseIntError, so we have to pattern match.
-        assert!(matches!(
-            PositiveNonzeroInteger::from_str("not a number"),
-            Err(ParsePosNonzeroError::ParseInt(_))
-        ));
-    }
-
-    #[test]
-    fn test_negative() {
-        assert_eq!(
-            PositiveNonzeroInteger::from_str("-555"),
-            Err(ParsePosNonzeroError::Creation(CreationError::Negative))
-        );
-    }
-
-    #[test]
-    fn test_zero() {
-        assert_eq!(
-            PositiveNonzeroInteger::from_str("0"),
-            Err(ParsePosNonzeroError::Creation(CreationError::Zero))
-        );
-    }
-
-    #[test]
-    fn test_positive() {
-        let x = PositiveNonzeroInteger::new(42);
-        assert!(x.is_ok());
-        assert_eq!(PositiveNonzeroInteger::from_str("42"), Ok(x.unwrap()));
-    }
-}

exercises/advanced_errors/advanced_errs2.rs

@@ -1,202 +0,0 @@
-// advanced_errs2.rs
-
-// This exercise demonstrates a few traits that are useful for custom error
-// types to implement, especially so that other code can consume the custom
-// error type more usefully.
-
-// Make this compile, and make the tests pass!
-// Execute `rustlings hint advanced_errs2` for hints.
-
-// Steps:
-// 1. Implement a missing trait so that `main()` will compile.
-// 2. Complete the partial implementation of `From` for
-//    `ParseClimateError`.
-// 3. Handle the missing error cases in the `FromStr` implementation for
-//    `Climate`.
-// 4. Complete the partial implementation of `Display` for
-//    `ParseClimateError`.
-
-// I AM NOT DONE
-
-use std::error::Error;
-use std::fmt::{self, Display, Formatter};
-use std::num::{ParseFloatError, ParseIntError};
-use std::str::FromStr;
-
-// This is the custom error type that we will be using for the parser for
-// `Climate`.
-#[derive(Debug, PartialEq)]
-enum ParseClimateError {
-    Empty,
-    BadLen,
-    NoCity,
-    ParseInt(ParseIntError),
-    ParseFloat(ParseFloatError),
-}
-
-// This `From` implementation allows the `?` operator to work on
-// `ParseIntError` values.
-impl From<ParseIntError> for ParseClimateError {
-    fn from(e: ParseIntError) -> Self {
-        Self::ParseInt(e)
-    }
-}
-
-// This `From` implementation allows the `?` operator to work on
-// `ParseFloatError` values.
-impl From<ParseFloatError> for ParseClimateError {
-    fn from(e: ParseFloatError) -> Self {
-        // TODO: Complete this function
-    }
-}
-
-// TODO: Implement a missing trait so that `main()` below will compile. It
-// is not necessary to implement any methods inside the missing trait.
-
-// The `Display` trait allows for other code to obtain the error formatted
-// as a user-visible string.
-impl Display for ParseClimateError {
-    // TODO: Complete this function so that it produces the correct strings
-    // for each error variant.
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        // Imports the variants to make the following code more compact.
-        use ParseClimateError::*;
-        match self {
-            NoCity => write!(f, "no city name"),
-            ParseFloat(e) => write!(f, "error parsing temperature: {}", e),
-        }
-    }
-}
-
-#[derive(Debug, PartialEq)]
-struct Climate {
-    city: String,
-    year: u32,
-    temp: f32,
-}
-
-// Parser for `Climate`.
-// 1. Split the input string into 3 fields: city, year, temp.
-// 2. Return an error if the string is empty or has the wrong number of
-//    fields.
-// 3. Return an error if the city name is empty.
-// 4. Parse the year as a `u32` and return an error if that fails.
-// 5. Parse the temp as a `f32` and return an error if that fails.
-// 6. Return an `Ok` value containing the completed `Climate` value.
-impl FromStr for Climate {
-    type Err = ParseClimateError;
-    // TODO: Complete this function by making it handle the missing error
-    // cases.
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let v: Vec<_> = s.split(',').collect();
-        let (city, year, temp) = match &v[..] {
-            [city, year, temp] => (city.to_string(), year, temp),
-            _ => return Err(ParseClimateError::BadLen),
-        };
-        let year: u32 = year.parse()?;
-        let temp: f32 = temp.parse()?;
-        Ok(Climate { city, year, temp })
-    }
-}
-
-// Don't change anything below this line (other than to enable ignored
-// tests).
-
-fn main() -> Result<(), Box<dyn Error>> {
-    println!("{:?}", "Hong Kong,1999,25.7".parse::<Climate>()?);
-    println!("{:?}", "".parse::<Climate>()?);
-    Ok(())
-}
-
-#[cfg(test)]
-mod test {
-    use super::*;
-    #[test]
-    fn test_empty() {
-        let res = "".parse::<Climate>();
-        assert_eq!(res, Err(ParseClimateError::Empty));
-        assert_eq!(res.unwrap_err().to_string(), "empty input");
-    }
-    #[test]
-    fn test_short() {
-        let res = "Boston,1991".parse::<Climate>();
-        assert_eq!(res, Err(ParseClimateError::BadLen));
-        assert_eq!(res.unwrap_err().to_string(), "incorrect number of fields");
-    }
-    #[test]
-    fn test_long() {
-        let res = "Paris,1920,17.2,extra".parse::<Climate>();
-        assert_eq!(res, Err(ParseClimateError::BadLen));
-        assert_eq!(res.unwrap_err().to_string(), "incorrect number of fields");
-    }
-    #[test]
-    fn test_no_city() {
-        let res = ",1997,20.5".parse::<Climate>();
-        assert_eq!(res, Err(ParseClimateError::NoCity));
-        assert_eq!(res.unwrap_err().to_string(), "no city name");
-    }
-    #[test]
-    fn test_parse_int_neg() {
-        let res = "Barcelona,-25,22.3".parse::<Climate>();
-        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
-        let err = res.unwrap_err();
-        if let ParseClimateError::ParseInt(ref inner) = err {
-            assert_eq!(
-                err.to_string(),
-                format!("error parsing year: {}", inner.to_string())
-            );
-        } else {
-            unreachable!();
-        };
-    }
-    #[test]
-    fn test_parse_int_bad() {
-        let res = "Beijing,foo,15.0".parse::<Climate>();
-        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
-        let err = res.unwrap_err();
-        if let ParseClimateError::ParseInt(ref inner) = err {
-            assert_eq!(
-                err.to_string(),
-                format!("error parsing year: {}", inner.to_string())
-            );
-        } else {
-            unreachable!();
-        };
-    }
-    #[test]
-    fn test_parse_float() {
-        let res = "Manila,2001,bar".parse::<Climate>();
-        assert!(matches!(res, Err(ParseClimateError::ParseFloat(_))));
-        let err = res.unwrap_err();
-        if let ParseClimateError::ParseFloat(ref inner) = err {
-            assert_eq!(
-                err.to_string(),
-                format!("error parsing temperature: {}", inner.to_string())
-            );
-        } else {
-            unreachable!();
-        };
-    }
-    #[test]
-    fn test_parse_good() {
-        let res = "Munich,2015,23.1".parse::<Climate>();
-        assert_eq!(
-            res,
-            Ok(Climate {
-                city: "Munich".to_string(),
-                year: 2015,
-                temp: 23.1,
-            })
-        );
-    }
-    #[test]
-    #[ignore]
-    fn test_downcast() {
-        let res = "São Paulo,-21,28.5".parse::<Climate>();
-        assert!(matches!(res, Err(ParseClimateError::ParseInt(_))));
-        let err = res.unwrap_err();
-        let inner: Option<&(dyn Error + 'static)> = err.source();
-        assert!(inner.is_some());
-        assert!(inner.unwrap().is::<ParseIntError>());
-    }
-}

exercises/advanced_errors/mod.rs

@@ -1,2 +0,0 @@
-mod advanced_errs1;
-mod advanced_errs2;

exercises/clippy/clippy1.rs

@@ -4,7 +4,7 @@
 //
 // For these exercises the code will fail to compile when there are clippy warnings
 // check clippy's suggestions from the output to solve the exercise.
-// Execute `rustlings hint clippy1` for hints :)
+// Execute `rustlings hint clippy1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/clippy/clippy2.rs

@@ -1,5 +1,5 @@
 // clippy2.rs
-// Make me compile! Execute `rustlings hint clippy2` for hints :)
+// Execute `rustlings hint clippy2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/clippy/clippy3.rs

@@ -0,0 +1,28 @@
+// clippy3.rs
+// Here's a couple more easy Clippy fixes, so you can see its utility.
+
+// I AM NOT DONE
+
+#[allow(unused_variables, unused_assignments)]
+fn main() {
+    let my_option: Option<()> = None;
+    if my_option.is_none() {
+        my_option.unwrap();
+    }
+
+    let my_arr = &[
+        -1, -2, -3
+        -4, -5, -6
+    ];
+    println!("My array! Here it is: {:?}", my_arr);
+
+    let my_empty_vec = vec![1, 2, 3, 4, 5].resize(0, 5);
+    println!("This Vec is empty, see? {:?}", my_empty_vec);
+
+    let mut value_a = 45;
+    let mut value_b = 66;
+    // Let's swap these two!
+    value_a = value_b;
+    value_b = value_a;
+    println!("value a: {}; value b: {}", value_a, value_b);
+}

exercises/clippy/mod.rs

@@ -1,2 +0,0 @@
-mod clippy1;
-mod clippy2;

exercises/collections/README.md

@@ -1,23 +0,0 @@
-# Collections
-
-Rust’s standard library includes a number of very useful data
-structures called collections. Most other data types represent one
-specific value, but collections can contain multiple values. Unlike
-the built-in array and tuple types, the data these collections point
-to is stored on the heap, which means the amount of data does not need
-to be known at compile time and can grow or shrink as the program
-runs.
-
-This exercise will get you familiar with two fundamental data
-structures that are used very often in Rust programs:
-
-* A *vector* allows you to store a variable number of values next to
-  each other.
-* A *hash map* allows you to associate a value with a particular key.
-  You may also know this by the names [*unordered map* in C++](https://en.cppreference.com/w/cpp/container/unordered_map), 
-  [*dictionary* in Python](https://docs.python.org/3/tutorial/datastructures.html#dictionaries) or an *associative array* in other languages.
-
-## Further information
-
-- [Storing Lists of Values with Vectors](https://doc.rust-lang.org/stable/book/ch08-01-vectors.html)
-- [Storing Keys with Associated Values in Hash Maps](https://doc.rust-lang.org/book/ch08-03-hash-maps.html)

exercises/collections/mod.rs

@@ -1,4 +0,0 @@
-mod hashmap1;
-mod hashmap2;
-mod vec1;
-mod vec2;

exercises/conversions/as_ref_mut.rs

@@ -1,6 +1,7 @@
 // AsRef and AsMut allow for cheap reference-to-reference conversions.
 // Read more about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html
 // and https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
+// Execute `rustlings hint as_ref_mut` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -16,10 +17,10 @@ fn char_counter<T>(arg: T) -> usize {
     arg.as_ref().chars().count()
 }
 
-fn main() {
-    let s = "Café au lait";
-    println!("{}", char_counter(s));
-    println!("{}", byte_counter(s));
+// Squares a number using AsMut. Add the trait bound as is appropriate and
+// implement the function body.
+fn num_sq<T>(arg: &mut T) {
+    ???
 }
 
 #[cfg(test)]
@@ -49,4 +50,11 @@ mod tests {
         let s = String::from("Cafe au lait");
         assert_eq!(char_counter(s.clone()), byte_counter(s));
     }
+
+    #[test]
+    fn mult_box() {
+        let mut num: Box<u32> = Box::new(3);
+        num_sq(&mut num);
+        assert_eq!(*num, 9);
+    }
 }

exercises/conversions/from_into.rs

@@ -1,6 +1,8 @@
 // The From trait is used for value-to-value conversions.
 // If From is implemented correctly for a type, the Into trait should work conversely.
 // You can read more about it at https://doc.rust-lang.org/std/convert/trait.From.html
+// Execute `rustlings hint from_into` or use the `hint` watch subcommand for a hint.
+
 #[derive(Debug)]
 struct Person {
     name: String,

exercises/conversions/from_str.rs

@@ -4,6 +4,8 @@
 // Additionally, upon implementing FromStr, you can use the `parse` method
 // on strings to generate an object of the implementor type.
 // You can read more about it at https://doc.rust-lang.org/std/str/trait.FromStr.html
+// Execute `rustlings hint from_str` or use the `hint` watch subcommand for a hint.
+
 use std::num::ParseIntError;
 use std::str::FromStr;
 
@@ -37,6 +39,9 @@ enum ParsePersonError {
 //    with something like `"4".parse::<usize>()`
 // 6. If while extracting the name and the age something goes wrong, an error should be returned
 // If everything goes well, then return a Result of a Person object
+//
+// As an aside: `Box<dyn Error>` implements `From<&'_ str>`. This means that if you want to return a
+// string error message, you can do so via just using return `Err("my error message".into())`.
 
 impl FromStr for Person {
     type Err = ParsePersonError;

exercises/conversions/mod.rs

@@ -1,5 +0,0 @@
-mod as_ref_mut;
-mod from_into;
-mod from_str;
-mod try_from_into;
-mod using_as;

exercises/conversions/try_from_into.rs

@@ -3,6 +3,8 @@
 // Basically, this is the same as From. The main difference is that this should return a Result type
 // instead of the target type itself.
 // You can read more about it at https://doc.rust-lang.org/std/convert/trait.TryFrom.html
+// Execute `rustlings hint try_from_into` or use the `hint` watch subcommand for a hint.
+
 use std::convert::{TryFrom, TryInto};
 
 #[derive(Debug, PartialEq)]
@@ -54,7 +56,7 @@ impl TryFrom<&[i16]> for Color {
 }
 
 fn main() {
-    // Use the `from` function
+    // Use the `try_from` function
     let c1 = Color::try_from((183, 65, 14));
     println!("{:?}", c1);
 

exercises/conversions/using_as.rs

@@ -4,11 +4,12 @@
 //
 // The goal is to make sure that the division does not fail to compile
 // and returns the proper type.
+// Execute `rustlings hint using_as` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
 fn average(values: &[f64]) -> f64 {
-    let total = values.iter().fold(0.0, |a, b| a + b);
+    let total = values.iter().sum::<f64>();
     total / values.len()
 }
 

exercises/enums/enums1.rs

@@ -1,5 +1,5 @@
 // enums1.rs
-// Make me compile! Execute `rustlings hint enums1` for hints!
+// No hints this time! ;)
 
 // I AM NOT DONE
 

exercises/enums/enums2.rs

@@ -1,5 +1,5 @@
 // enums2.rs
-// Make me compile! Execute `rustlings hint enums2` for hints!
+// Execute `rustlings hint enums2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/enums/enums3.rs

@@ -1,5 +1,6 @@
 // enums3.rs
 // Address all the TODOs to make the tests pass!
+// Execute `rustlings hint enums3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/enums/mod.rs

@@ -1,3 +0,0 @@
-mod enums1;
-mod enums2;
-mod enums3;

exercises/error_handling/errors1.rs

@@ -3,16 +3,16 @@
 // you pass it an empty string. It'd be nicer if it explained what the problem
 // was, instead of just sometimes returning `None`. Thankfully, Rust has a similar
 // construct to `Option` that can be used to express error conditions. Let's use it!
-// Execute `rustlings hint errors1` for hints!
+// Execute `rustlings hint errors1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
 pub fn generate_nametag_text(name: String) -> Option<String> {
-    if name.len() > 0 {
-        Some(format!("Hi! My name is {}", name))
-    } else {
+    if name.is_empty() {
         // Empty names aren't allowed.
         None
+    } else {
+        Some(format!("Hi! My name is {}", name))
     }
 }
 

exercises/error_handling/errors2.rs

@@ -14,7 +14,8 @@
 // and add.
 
 // There are at least two ways to implement this that are both correct-- but
-// one is a lot shorter! Execute `rustlings hint errors2` for hints to both ways.
+// one is a lot shorter!
+// Execute `rustlings hint errors2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/error_handling/errors3.rs

@@ -2,7 +2,7 @@
 // This is a program that is trying to use a completed version of the
 // `total_cost` function from the previous exercise. It's not working though!
 // Why not? What should we do to fix it?
-// Execute `rustlings hint errors3` for hints!
+// Execute `rustlings hint errors3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/error_handling/errors4.rs

@@ -1,5 +1,5 @@
 // errors4.rs
-// Make this test pass! Execute `rustlings hint errors4` for hints :)
+// Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -14,6 +14,7 @@ enum CreationError {
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        // Hmm...? Why is this only returning an Ok value?
         Ok(PositiveNonzeroInteger(value as u64))
     }
 }

exercises/error_handling/errors5.rs

@@ -1,8 +1,20 @@
 // errors5.rs
 
-// This program uses a completed version of the code from errors4.
-// It won't compile right now! Why?
-// Execute `rustlings hint errors5` for hints!
+// This program uses an altered version of the code from errors4.
+
+// This exercise uses some concepts that we won't get to until later in the course, like `Box` and the
+// `From` trait. It's not important to understand them in detail right now, but you can read ahead if you like.
+// For now, think of the `Box<dyn ...>` type as an "I want anything that does ???" type, which, given
+// Rust's usual standards for runtime safety, should strike you as somewhat lenient!
+
+// In short, this particular use case for boxes is for when you want to own a value and you care only that it is a 
+// type which implements a particular trait. To do so, The Box is declared as of type Box<dyn Trait> where Trait is the trait
+// the compiler looks for on any value used in that context. For this exercise, that context is the potential errors
+// which can be returned in a Result.
+
+// What can we use to describe both errors? In other words, is there a trait which both errors implement?
+
+// Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -11,7 +23,7 @@ use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), ParseIntError> {
+fn main() -> Result<(), Box<dyn ???>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);

exercises/error_handling/errors6.rs

@@ -6,7 +6,7 @@
 // we define a custom error type to make it possible for callers to decide
 // what to do next when our function returns an error.
 
-// Make these tests pass! Execute `rustlings hint errors6` for hints :)
+// Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -20,7 +20,11 @@ enum ParsePosNonzeroError {
 }
 
 impl ParsePosNonzeroError {
+    fn from_creation(err: CreationError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::Creation(err)
+    }
     // TODO: add another error conversion function here.
+    // fn from_parseint...
 }
 
 fn parse_pos_nonzero(s: &str)

exercises/error_handling/mod.rs

@@ -1,6 +0,0 @@
-mod errors1;
-mod errors2;
-mod errors3;
-mod errors4;
-mod errors5;
-mod errors6;

exercises/functions/README.md

@@ -1,6 +1,7 @@
 # Functions
 
-Here, you'll learn how to write functions and how Rust's compiler can trace things way back.
+Here, you'll learn how to write functions and how the Rust compiler can help you debug errors even
+in more complex code.
 
 ## Further information
 

exercises/functions/functions1.rs

@@ -1,5 +1,5 @@
 // functions1.rs
-// Make me compile! Execute `rustlings hint functions1` for hints :)
+// Execute `rustlings hint functions1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/functions/functions2.rs

@@ -1,5 +1,5 @@
 // functions2.rs
-// Make me compile! Execute `rustlings hint functions2` for hints :)
+// Execute `rustlings hint functions2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/functions/functions3.rs

@@ -1,5 +1,5 @@
 // functions3.rs
-// Make me compile! Execute `rustlings hint functions3` for hints :)
+// Execute `rustlings hint functions3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/functions/functions4.rs

@@ -1,8 +1,11 @@
 // functions4.rs
-// Make me compile! Execute `rustlings hint functions4` for hints :)
+// Execute `rustlings hint functions4` or use the `hint` watch subcommand for a hint.
 
 // This store is having a sale where if the price is an even number, you get
 // 10 Rustbucks off, but if it's an odd number, it's 3 Rustbucks off.
+// (Don't worry about the function bodies themselves, we're only interested
+// in the signatures for now. If anything, this is a good way to peek ahead
+// to future exercises!)
 
 // I AM NOT DONE
 

exercises/functions/functions5.rs

@@ -1,11 +1,11 @@
 // functions5.rs
-// Make me compile! Execute `rustlings hint functions5` for hints :)
+// Execute `rustlings hint functions5` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
 fn main() {
     let answer = square(3);
-    println!("The answer is {}", answer);
+    println!("The square of 3 is {}", answer);
 }
 
 fn square(num: i32) -> i32 {

exercises/functions/mod.rs

@@ -1,5 +0,0 @@
-mod functions1;
-mod functions2;
-mod functions3;
-mod functions4;
-mod functions5;

exercises/generics/generics1.rs

@@ -1,7 +1,7 @@
 // This shopping list program isn't compiling!
 // Use your knowledge of generics to fix it.
 
-// Execute `rustlings hint generics1` for hints!
+// Execute `rustlings hint generics1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/generics/generics2.rs

@@ -1,7 +1,7 @@
 // This powerful wrapper provides the ability to store a positive integer value.
 // Rewrite it using generics so that it supports wrapping ANY type.
 
-// Execute `rustlings hint generics2` for hints!
+// Execute `rustlings hint generics2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/generics/generics3.rs

@@ -1,58 +0,0 @@
-// An imaginary magical school has a new report card generation system written in Rust!
-// Currently the system only supports creating report cards where the student's grade
-// is represented numerically (e.g. 1.0 -> 5.5).
-// However, the school also issues alphabetical grades (A+ -> F-) and needs
-// to be able to print both types of report card!
-
-// Make the necessary code changes in the struct ReportCard and the impl block
-// to support alphabetical report cards. Change the Grade in the second test to "A+"
-// to show that your changes allow alphabetical grades.
-
-// Execute 'rustlings hint generics3' for hints!
-
-// I AM NOT DONE
-
-pub struct ReportCard {
-    pub grade: f32,
-    pub student_name: String,
-    pub student_age: u8,
-}
-
-impl ReportCard {
-    pub fn print(&self) -> String {
-        format!("{} ({}) - achieved a grade of {}",
-            &self.student_name, &self.student_age, &self.grade)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn generate_numeric_report_card() {
-        let report_card = ReportCard {
-            grade: 2.1,
-            student_name: "Tom Wriggle".to_string(),
-            student_age: 12,
-        };
-        assert_eq!(
-            report_card.print(),
-            "Tom Wriggle (12) - achieved a grade of 2.1"
-        );
-    }
-
-    #[test]
-    fn generate_alphabetic_report_card() {
-        // TODO: Make sure to change the grade here after you finish the exercise.
-        let report_card = ReportCard {
-            grade: 2.1,
-            student_name: "Gary Plotter".to_string(),
-            student_age: 11,
-        };
-        assert_eq!(
-            report_card.print(),
-            "Gary Plotter (11) - achieved a grade of A+"
-        );
-    }
-}

exercises/generics/mod.rs

@@ -1,3 +0,0 @@
-mod generics1;
-mod generics2;
-mod generics3;

exercises/hashmaps/README.md

@@ -0,0 +1,11 @@
+# Hashmaps
+A *hash map* allows you to associate a value with a particular key.
+You may also know this by the names [*unordered map* in C++](https://en.cppreference.com/w/cpp/container/unordered_map), 
+[*dictionary* in Python](https://docs.python.org/3/tutorial/datastructures.html#dictionaries) or an *associative array* in other languages.
+
+This is the other data structure that we've been talking about before, when
+talking about Vecs.
+
+## Further information
+
+- [Storing Keys with Associated Values in Hash Maps](https://doc.rust-lang.org/book/ch08-03-hash-maps.html)

exercises/hashmaps/hashmaps1.rs

@@ -1,4 +1,4 @@
-// hashmap1.rs
+// hashmaps1.rs
 // A basket of fruits in the form of a hash map needs to be defined.
 // The key represents the name of the fruit and the value represents
 // how many of that particular fruit is in the basket. You have to put
@@ -8,8 +8,7 @@
 //
 // Make me compile and pass the tests!
 //
-// Execute the command `rustlings hint hashmap1` if you need
-// hints.
+// Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/hashmaps/hashmaps2.rs

@@ -1,4 +1,4 @@
-// hashmap2.rs
+// hashmaps2.rs
 
 // A basket of fruits in the form of a hash map is given. The key
 // represents the name of the fruit and the value represents how many
@@ -9,8 +9,7 @@
 //
 // Make me pass the tests!
 //
-// Execute the command `rustlings hint hashmap2` if you need
-// hints.
+// Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/hashmaps/hashmaps3.rs

@@ -0,0 +1,87 @@
+// hashmaps3.rs
+
+// A list of scores (one per line) of a soccer match is given. Each line
+// is of the form :
+// <team_1_name>,<team_2_name>,<team_1_goals>,<team_2_goals>
+// Example: England,France,4,2 (England scored 4 goals, France 2).
+
+// You have to build a scores table containing the name of the team, goals
+// the team scored, and goals the team conceded. One approach to build
+// the scores table is to use a Hashmap. The solution is partially
+// written to use a Hashmap, complete it to pass the test.
+
+// Make me pass the tests!
+
+// Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+// A structure to store team name and its goal details.
+struct Team {
+    name: String,
+    goals_scored: u8,
+    goals_conceded: u8,
+}
+
+fn build_scores_table(results: String) -> HashMap<String, Team> {
+    // The name of the team is the key and its associated struct is the value.
+    let mut scores: HashMap<String, Team> = HashMap::new();
+
+    for r in results.lines() {
+        let v: Vec<&str> = r.split(',').collect();
+        let team_1_name = v[0].to_string();
+        let team_1_score: u8 = v[2].parse().unwrap();
+        let team_2_name = v[1].to_string();
+        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 number of goals conceded from team_2, and similarly
+        // goals scored by team_2 will be the number of goals conceded by
+        // team_1.
+    }
+    scores
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn get_results() -> String {
+        let results = "".to_string()
+            + "England,France,4,2\n"
+            + "France,Italy,3,1\n"
+            + "Poland,Spain,2,0\n"
+            + "Germany,England,2,1\n";
+        results
+    }
+
+    #[test]
+    fn build_scores() {
+        let scores = build_scores_table(get_results());
+
+        let mut keys: Vec<&String> = scores.keys().collect();
+        keys.sort();
+        assert_eq!(
+            keys,
+            vec!["England", "France", "Germany", "Italy", "Poland", "Spain"]
+        );
+    }
+
+    #[test]
+    fn validate_team_score_1() {
+        let scores = build_scores_table(get_results());
+        let team = scores.get("England").unwrap();
+        assert_eq!(team.goals_scored, 5);
+        assert_eq!(team.goals_conceded, 4);
+    }
+
+    #[test]
+    fn validate_team_score_2() {
+        let scores = build_scores_table(get_results());
+        let team = scores.get("Spain").unwrap();
+        assert_eq!(team.goals_scored, 0);
+        assert_eq!(team.goals_conceded, 2);
+    }
+}

exercises/if/README.md

@@ -1,6 +1,6 @@
 # If
 
-`if`, the most basic type of control flow, is what you'll learn here.
+`if`, the most basic (but still surprisingly versatile!) type of control flow, is what you'll learn here.
 
 ## Further information
 

exercises/if/if1.rs

@@ -1,4 +1,5 @@
 // if1.rs
+// Execute `rustlings hint if1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -7,7 +8,6 @@ pub fn bigger(a: i32, b: i32) -> i32 {
     // Do not use:
     // - another function call
     // - additional variables
-    // Execute `rustlings hint if1` for hints
 }
 
 // Don't mind this for now :)

exercises/if/if2.rs

@@ -2,11 +2,11 @@
 
 // Step 1: Make me compile!
 // Step 2: Get the bar_for_fuzz and default_to_baz tests passing!
-// Execute the command `rustlings hint if2` if you want a hint :)
+// Execute `rustlings hint if2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
-pub fn fizz_if_foo(fizzish: &str) -> &str {
+pub fn foo_if_fizz(fizzish: &str) -> &str {
     if fizzish == "fizz" {
         "foo"
     } else {
@@ -21,16 +21,16 @@ mod tests {
 
     #[test]
     fn foo_for_fizz() {
-        assert_eq!(fizz_if_foo("fizz"), "foo")
+        assert_eq!(foo_if_fizz("fizz"), "foo")
     }
 
     #[test]
     fn bar_for_fuzz() {
-        assert_eq!(fizz_if_foo("fuzz"), "bar")
+        assert_eq!(foo_if_fizz("fuzz"), "bar")
     }
 
     #[test]
     fn default_to_baz() {
-        assert_eq!(fizz_if_foo("literally anything"), "baz")
+        assert_eq!(foo_if_fizz("literally anything"), "baz")
     }
 }

exercises/if/mod.rs

@@ -1,2 +0,0 @@
-mod if1;
-mod if2;

exercises/intro/intro1.rs

@@ -3,7 +3,11 @@
 // We sometimes encourage you to keep trying things on a given exercise, even
 // after you already figured it out. If you got everything working and feel
 // ready for the next exercise, remove the `I AM NOT DONE` comment below.
-// Execute the command `rustlings hint intro1` for a hint.
+// Execute `rustlings hint intro1` or use the `hint` watch subcommand for a hint.
+//
+// If you're running this using `rustlings watch`: The exercise file will be reloaded
+// when you change one of the lines below! Try adding a `println!` line, or try changing
+// what it outputs in your terminal. Try removing a semicolon and see what happens!
 
 // I AM NOT DONE
 
@@ -20,4 +24,7 @@ fn main() {
     println!("This exercise compiles successfully. The remaining exercises contain a compiler");
     println!("or logic error. The central concept behind Rustlings is to fix these errors and");
     println!("solve the exercises. Good luck!");
+    println!();
+    println!("The source for this exercise is in `exercises/intro/intro1.rs`. Have a look!");
+    println!("Going forward, the source of the exercises will always be in the success/failure output.");
 }

exercises/intro/intro2.rs

@@ -1,6 +1,6 @@
 // intro2.rs
 // Make the code print a greeting to the world.
-// Execute `rustlings hint intro2` for a hint.
+// Execute `rustlings hint intro2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/intro/mod.rs

@@ -1,2 +0,0 @@
-mod intro1;
-mod intro2;

exercises/lifetimes/README.md

@@ -0,0 +1,17 @@
+# Lifetimes
+
+Lifetimes tell the compiler how to check whether references live long
+enough to be valid in any given situation. For example lifetimes say
+"make sure parameter 'a' lives as long as parameter 'b' so that the return
+value is valid". 
+
+They are only necessary on borrows, i.e. references, 
+since copied parameters or moves are owned in their scope and cannot
+be referenced outside. Lifetimes mean that calling code of e.g. functions
+can be checked to make sure their arguments are valid. Lifetimes are 
+restrictive of their callers.
+
+## Further information
+
+- [Validating References with Lifetimes](https://doc.rust-lang.org/book/ch10-03-lifetime-syntax.html)
+- [Lifetimes (in Rust By Example)](https://doc.rust-lang.org/stable/rust-by-example/scope/lifetime.html)

exercises/lifetimes/lifetimes1.rs

@@ -0,0 +1,26 @@
+// lifetimes1.rs
+//
+// The Rust compiler needs to know how to check whether supplied references are
+// valid, so that it can let the programmer know if a reference is at risk
+// of going out of scope before it is used. Remember, references are borrows
+// and do not own their own data. What if their owner goes out of scope?
+//
+// Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+fn longest(x: &str, y: &str) -> &str {
+    if x.len() > y.len() {
+        x
+    } else {
+        y
+    }
+}
+
+fn main() {
+    let string1 = String::from("abcd");
+    let string2 = "xyz";
+
+    let result = longest(string1.as_str(), string2);
+    println!("The longest string is {}", result);
+}

exercises/lifetimes/lifetimes2.rs

@@ -0,0 +1,27 @@
+// lifetimes2.rs
+//
+// So if the compiler is just validating the references passed
+// to the annotated parameters and the return type, what do
+// we need to change?
+//
+// Execute `rustlings hint lifetimes2` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
+    if x.len() > y.len() {
+        x
+    } else {
+        y
+    }
+}
+
+fn main() {
+    let string1 = String::from("long string is long");
+    let result;
+    {
+        let string2 = String::from("xyz");
+        result = longest(string1.as_str(), string2.as_str());
+    }
+    println!("The longest string is {}", result);
+}

exercises/lifetimes/lifetimes3.rs

@@ -0,0 +1,20 @@
+// lifetimes3.rs
+//
+// Lifetimes are also needed when structs hold references.
+//
+// Execute `rustlings hint lifetimes3` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+struct Book {
+    author: &str,
+    title: &str,
+}
+
+fn main() {
+    let name = String::from("Jill Smith");
+    let title = String::from("Fish Flying");
+    let book = Book { author: &name, title: &title };
+
+    println!("{} by {}", book.title, book.author);
+}

exercises/macros/README.md

@@ -7,4 +7,4 @@ macros. Instead, we'll show you how to use and create them.
 ## Further information
 
 - [Macros](https://doc.rust-lang.org/book/ch19-06-macros.html)
-- [The Little Book of Rust Macros](https://danielkeep.github.io/tlborm/book/index.html)
+- [The Little Book of Rust Macros](https://veykril.github.io/tlborm/)

exercises/macros/macros1.rs

@@ -1,5 +1,5 @@
 // macros1.rs
-// Make me compile! Execute `rustlings hint macros1` for hints :)
+// Execute `rustlings hint macros1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/macros/macros2.rs

@@ -1,5 +1,5 @@
 // macros2.rs
-// Make me compile! Execute `rustlings hint macros2` for hints :)
+// Execute `rustlings hint macros2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/macros/macros3.rs

@@ -1,6 +1,6 @@
 // macros3.rs
 // Make me compile, without taking the macro out of the module!
-// Execute `rustlings hint macros3` for hints :)
+// Execute `rustlings hint macros3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/macros/macros4.rs

@@ -1,5 +1,5 @@
 // macros4.rs
-// Make me compile! Execute `rustlings hint macros4` for hints :)
+// Execute `rustlings hint macros4` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/macros/mod.rs

@@ -1,4 +0,0 @@
-mod macros1;
-mod macros2;
-mod macros3;
-mod macros4;

exercises/mod.rs

@@ -1,26 +0,0 @@
-mod advanced_errors;
-mod clippy;
-mod collections;
-mod conversions;
-mod enums;
-mod error_handling;
-mod functions;
-mod generics;
-mod r#if;
-mod intro;
-mod macros;
-mod modules;
-mod move_semantics;
-mod option;
-mod primitive_types;
-mod quiz1;
-mod quiz2;
-mod quiz3;
-mod quiz4;
-mod standard_library_types;
-mod strings;
-mod structs;
-mod tests;
-mod threads;
-mod traits;
-mod variables;

exercises/modules/mod.rs

@@ -1,3 +0,0 @@
-mod modules1;
-mod modules2;
-mod modules3;

exercises/modules/modules1.rs

@@ -1,5 +1,5 @@
 // modules1.rs
-// Make me compile! Execute `rustlings hint modules1` for hints :)
+// Execute `rustlings hint modules1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/modules/modules2.rs

@@ -1,12 +1,11 @@
 // modules2.rs
 // You can bring module paths into scopes and provide new names for them with the
 // 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
-// Make me compile! Execute `rustlings hint modules2` for hints :)
+// Execute `rustlings hint modules2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
 mod delicious_snacks {
-
     // TODO: Fix these use statements
     use self::fruits::PEAR as ???
     use self::veggies::CUCUMBER as ???

exercises/modules/modules3.rs

@@ -3,7 +3,7 @@
 // and especially from the Rust standard library into your scope.
 // Bring SystemTime and UNIX_EPOCH
 // from the std::time module. Bonus style points if you can do it with one line!
-// Make me compile! Execute `rustlings hint modules3` for hints :)
+// Execute `rustlings hint modules3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/move_semantics/mod.rs

@@ -1,6 +0,0 @@
-mod move_semantics1;
-mod move_semantics2;
-mod move_semantics3;
-mod move_semantics4;
-mod move_semantics5;
-mod move_semantics6;

exercises/move_semantics/move_semantics1.rs

@@ -1,5 +1,5 @@
 // move_semantics1.rs
-// Make me compile! Execute `rustlings hint move_semantics1` for hints :)
+// Execute `rustlings hint move_semantics1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/move_semantics/move_semantics2.rs

@@ -1,6 +1,6 @@
 // move_semantics2.rs
 // Make me compile without changing line 13 or moving line 10!
-// Execute `rustlings hint move_semantics2` for hints :)
+// Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/move_semantics/move_semantics3.rs

@@ -1,7 +1,7 @@
 // move_semantics3.rs
 // Make me compile without adding new lines-- just changing existing lines!
 // (no lines with multiple semicolons necessary!)
-// Execute `rustlings hint move_semantics3` for hints :)
+// Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/move_semantics/move_semantics4.rs

@@ -1,8 +1,8 @@
 // move_semantics4.rs
-// Refactor this code so that instead of having `vec0` and creating the vector
-// in `fn main`, we create it within `fn fill_vec` and transfer the
-// freshly created vector from fill_vec to its caller.
-// Execute `rustlings hint move_semantics4` for hints!
+// Refactor this code so that instead of passing `vec0` into the `fill_vec` function,
+// the Vector gets created in the function itself and passed back to the main
+// function.
+// Execute `rustlings hint move_semantics4` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/move_semantics/move_semantics5.rs

@@ -1,7 +1,7 @@
 // move_semantics5.rs
 // Make me compile only by reordering the lines in `main()`, but without
 // adding, changing or removing any of them.
-// Execute `rustlings hint move_semantics5` for hints :)
+// Execute `rustlings hint move_semantics5` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/move_semantics/move_semantics6.rs

@@ -1,6 +1,6 @@
 // move_semantics6.rs
-// Make me compile! `rustlings hint move_semantics6` for hints
-// You can't change anything except adding or removing references
+// Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand for a hint.
+// You can't change anything except adding or removing references.
 
 // I AM NOT DONE
 

exercises/option/mod.rs

@@ -1,3 +0,0 @@
-mod option1;
-mod option2;
-mod option3;

exercises/option/option1.rs

@@ -1,23 +0,0 @@
-// option1.rs
-// Make me compile! Execute `rustlings hint option1` for hints
-
-// I AM NOT DONE
-
-// you can modify anything EXCEPT for this function's signature
-fn print_number(maybe_number: Option<u16>) {
-    println!("printing: {}", maybe_number.unwrap());
-}
-
-fn main() {
-    print_number(13);
-    print_number(99);
-
-    let mut numbers: [Option<u16>; 5];
-    for iter in 0..5 {
-        let number_to_add: u16 = {
-            ((iter * 1235) + 2) / (4 * 16)
-        };
-
-        numbers[iter as usize] = number_to_add;
-    }
-}

exercises/options/README.md

@@ -1,4 +1,4 @@
-# Option
+# Options
 
 Type Option represents an optional value: every Option is either Some and contains a value, or None, and does not. 
 Option types are very common in Rust code, as they have a number of uses:

exercises/options/options1.rs

@@ -0,0 +1,35 @@
+// options1.rs
+// Execute `rustlings hint options1` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+// This function returns how much icecream there is left in the fridge.
+// If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
+// all, so there'll be no more left :(
+// TODO: Return an Option!
+fn maybe_icecream(time_of_day: u16) -> Option<u16> {
+    // We use the 24-hour system here, so 10PM is a value of 22
+    // The Option output should gracefully handle cases where time_of_day > 24.
+    ???
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn check_icecream() {
+        assert_eq!(maybe_icecream(9), Some(5));
+        assert_eq!(maybe_icecream(10), Some(0));
+        assert_eq!(maybe_icecream(23), Some(0));
+        assert_eq!(maybe_icecream(22), Some(0));
+        assert_eq!(maybe_icecream(25), None);
+    }
+
+    #[test]
+    fn raw_value() {
+        // TODO: Fix this test. How do you get at the value contained in the Option?
+        let icecreams = maybe_icecream(12);
+        assert_eq!(icecreams, 0);
+    }
+}

exercises/options/options2.rs

@@ -1,5 +1,5 @@
-// option2.rs
-// Make me compile! Execute `rustlings hint option2` for hints
+// options2.rs
+// Execute `rustlings hint options2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/options/options3.rs

@@ -1,5 +1,5 @@
-// option3.rs
-// Make me compile! Execute `rustlings hint option3` for hints
+// options3.rs
+// Execute `rustlings hint options3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/mod.rs

@@ -1,6 +0,0 @@
-mod primitive_types1;
-mod primitive_types2;
-mod primitive_types3;
-mod primitive_types4;
-mod primitive_types5;
-mod primitive_types6;

exercises/primitive_types/primitive_types2.rs

@@ -7,6 +7,8 @@
 fn main() {
     // Characters (`char`)
 
+    // Note the _single_ quotes, these are different from the double quotes
+    // you've been seeing around.
     let my_first_initial = 'C';
     if my_first_initial.is_alphabetic() {
         println!("Alphabetical!");

exercises/primitive_types/primitive_types3.rs

@@ -1,6 +1,6 @@
 // primitive_types3.rs
 // Create an array with at least 100 elements in it where the ??? is.
-// Execute `rustlings hint primitive_types3` for hints!
+// Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types4.rs

@@ -1,6 +1,6 @@
 // primitive_types4.rs
 // Get a slice out of Array a where the ??? is so that the test passes.
-// Execute `rustlings hint primitive_types4` for hints!!
+// Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types5.rs

@@ -1,6 +1,6 @@
 // primitive_types5.rs
 // Destructure the `cat` tuple so that the println will work.
-// Execute `rustlings hint primitive_types5` for hints!
+// Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types6.rs

@@ -1,7 +1,7 @@
 // primitive_types6.rs
 // Use a tuple index to access the second element of `numbers`.
 // You can put the expression for the second element where ??? is so that the test passes.
-// Execute `rustlings hint primitive_types6` for hints!
+// Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/quiz1.rs

@@ -11,14 +11,14 @@
 // I AM NOT DONE
 
 // Put your function here!
-// fn calculate_apple_price {
+// fn calculate_price_of_apples {
 
 // Don't modify this function!
 #[test]
 fn verify_test() {
-    let price1 = calculate_apple_price(35);
-    let price2 = calculate_apple_price(40);
-    let price3 = calculate_apple_price(65);
+    let price1 = calculate_price_of_apples(35);
+    let price2 = calculate_price_of_apples(40);
+    let price3 = calculate_price_of_apples(65);
 
     assert_eq!(70, price1);
     assert_eq!(80, price2);

exercises/quiz2.rs

@@ -1,30 +1,62 @@
 // quiz2.rs
 // This is a quiz for the following sections:
 // - Strings
+// - Vecs
+// - Move semantics
+// - Modules
+// - Enums
 
-// Ok, here are a bunch of values-- some are `String`s, some are `&str`s. Your
-// task is to call one of these two functions on each value depending on what
-// you think each value is. That is, add either `string_slice` or `string`
-// before the parentheses on each line. If you're right, it will compile!
+// Let's build a little machine in form of a function.
+// As input, we're going to give a list of strings and commands. These commands
+// determine what action is going to be applied to the string. It can either be:
+// - Uppercase the string
+// - Trim the string
+// - Append "bar" to the string a specified amount of times
+// The exact form of this will be:
+// - The input is going to be a Vector of a 2-length tuple,
+//   the first element is the string, the second one is the command.
+// - The output element is going to be a Vector of strings.
+// Execute `rustlings hint quiz2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
-fn string_slice(arg: &str) {
-    println!("{}", arg);
-}
-fn string(arg: String) {
-    println!("{}", arg);
+pub enum Command {
+    Uppercase,
+    Trim,
+    Append(usize),
 }
 
-fn main() {
-    ???("blue");
-    ???("red".to_string());
-    ???(String::from("hi"));
-    ???("rust is fun!".to_owned());
-    ???("nice weather".into());
-    ???(format!("Interpolation {}", "Station"));
-    ???(&String::from("abc")[0..1]);
-    ???("  hello there ".trim());
-    ???("Happy Monday!".to_string().replace("Mon", "Tues"));
-    ???("mY sHiFt KeY iS sTiCkY".to_lowercase());
+mod my_module {
+    use super::Command;
+
+    // TODO: Complete the function signature!
+    pub fn transformer(input: ???) -> ??? {
+        // TODO: Complete the output declaration!
+        let mut output: ??? = vec![];
+        for (string, command) in input.iter() {
+            // TODO: Complete the function body. You can do it!
+        }
+        output
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    // TODO: What do we have to import to have `transformer` in scope?
+    use ???;
+    use super::Command;
+
+    #[test]
+    fn it_works() {
+        let output = transformer(vec![
+            ("hello".into(), Command::Uppercase),
+            (" all roads lead to rome! ".into(), Command::Trim),
+            ("foo".into(), Command::Append(1)),
+            ("bar".into(), Command::Append(5)),
+        ]);
+        assert_eq!(output[0], "HELLO");
+        assert_eq!(output[1], "all roads lead to rome!");
+        assert_eq!(output[2], "foobar");
+        assert_eq!(output[3], "barbarbarbarbarbar");
+    }
 }

exercises/quiz3.rs

@@ -1,16 +1,32 @@
 // quiz3.rs
-// This is a quiz for the following sections:
-// - Tests
+// This quiz tests:
+// - Generics
+// - Traits
+// An imaginary magical school has a new report card generation system written in Rust!
+// Currently the system only supports creating report cards where the student's grade
+// is represented numerically (e.g. 1.0 -> 5.5).
+// However, the school also issues alphabetical grades (A+ -> F-) and needs
+// to be able to print both types of report card!
 
-// This quiz isn't testing our function -- make it do that in such a way that
-// the test passes. Then write a second test that tests that we get the result
-// we expect to get when we call `times_two` with a negative number.
-// No hints, you can do this :)
+// Make the necessary code changes in the struct ReportCard and the impl block
+// to support alphabetical report cards. Change the Grade in the second test to "A+"
+// to show that your changes allow alphabetical grades.
+
+// Execute `rustlings hint quiz3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
-pub fn times_two(num: i32) -> i32 {
-    num * 2
+pub struct ReportCard {
+    pub grade: f32,
+    pub student_name: String,
+    pub student_age: u8,
+}
+
+impl ReportCard {
+    pub fn print(&self) -> String {
+        format!("{} ({}) - achieved a grade of {}",
+            &self.student_name, &self.student_age, &self.grade)
+    }
 }
 
 #[cfg(test)]
@@ -18,13 +34,29 @@ mod tests {
     use super::*;
 
     #[test]
-    fn returns_twice_of_positive_numbers() {
-        assert_eq!(times_two(4), ???);
+    fn generate_numeric_report_card() {
+        let report_card = ReportCard {
+            grade: 2.1,
+            student_name: "Tom Wriggle".to_string(),
+            student_age: 12,
+        };
+        assert_eq!(
+            report_card.print(),
+            "Tom Wriggle (12) - achieved a grade of 2.1"
+        );
     }
 
     #[test]
-    fn returns_twice_of_negative_numbers() {
-        // TODO replace unimplemented!() with an assert for `times_two(-4)`
-        unimplemented!()
+    fn generate_alphabetic_report_card() {
+        // TODO: Make sure to change the grade here after you finish the exercise.
+        let report_card = ReportCard {
+            grade: 2.1,
+            student_name: "Gary Plotter".to_string(),
+            student_age: 11,
+        };
+        assert_eq!(
+            report_card.print(),
+            "Gary Plotter (11) - achieved a grade of A+"
+        );
     }
 }

exercises/quiz4.rs

@@ -1,23 +0,0 @@
-// quiz4.rs
-// This quiz covers the sections:
-// - Modules
-// - Macros
-
-// Write a macro that passes the quiz! No hints this time, you can do it!
-
-// I AM NOT DONE
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_my_macro_world() {
-        assert_eq!(my_macro!("world!"), "Hello world!");
-    }
-
-    #[test]
-    fn test_my_macro_goodbye() {
-        assert_eq!(my_macro!("goodbye!"), "Hello goodbye!");
-    }
-}

exercises/standard_library_types/arc1.rs

@@ -16,7 +16,7 @@
 // Make this code compile by filling in a value for `shared_numbers` where the
 // first TODO comment is, and create an initial binding for `child_numbers`
 // where the second TODO comment is. Try not to create any copies of the `numbers` Vec!
-// Execute `rustlings hint arc1` for hints :)
+// Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -32,12 +32,7 @@ fn main() {
     for offset in 0..8 {
         let child_numbers = // TODO
         joinhandles.push(thread::spawn(move || {
-            let mut i = offset;
-            let mut sum = 0;
-            while i < child_numbers.len() {
-                sum += child_numbers[i];
-                i += 8;
-            }
+            let sum: u32 = child_numbers.iter().filter(|n| *n % 8 == offset).sum();
             println!("Sum of offset {} is {}", offset, sum);
         }));
     }