Merge pull request #1683 from rust-lang/all-contributors/add-OfirLauber

docs: add OfirLauber as a contributor for content

.clog.toml

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

.devcontainer/devcontainer.json

@@ -0,0 +1,17 @@
+{
+  "image": "mcr.microsoft.com/devcontainers/universal:2-linux",
+  "waitFor": "onCreateCommand",
+  "onCreateCommand": ".devcontainer/setup.sh",
+  "updateContentCommand": "cargo build",
+  "postCreateCommand": "",
+  "postAttachCommand": {
+    "server": "rustlings watch"
+  },
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "rust-lang.rust-analyzer"
+      ]
+    }
+  }
+}

.devcontainer/setup.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+curl https://sh.rustup.rs -sSf | sh -s -- -y
+
+# Update current shell environment variables after install to find rustup
+. "$HOME/.cargo/env"
+rustup install stable
+bash install.sh

.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

.envrc

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# Automatically Load nix devShell w/dotenv
+use flake

.github/workflows/rust.yml

@@ -0,0 +1,37 @@
+name: Rustlings Tests
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  fmt:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt
+      - uses: DavidAnson/markdownlint-cli2-action@v9
+        with:
+          globs: "exercises/**/*.md"
+      - name: Run cargo fmt
+        run: |
+          cargo fmt --all -- --check
+  test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: swatinem/rust-cache@v2
+      - name: Run cargo test
+        run: |
+          cargo test

.github/workflows/web.yml

@@ -0,0 +1,88 @@
+# Workflow to build your docs with oranda (and mdbook)
+# and deploy them to Github Pages
+name: Web
+
+# We're going to push to the gh-pages branch, so we need that permission
+permissions:
+  contents: write
+
+# What situations do we want to build docs in?
+# All of these work independently and can be removed / commented out
+# if you don't want oranda/mdbook running in that situation
+on:
+  # Check that a PR didn't break docs!
+  #
+  # Note that the "Deploy to Github Pages" step won't run in this mode,
+  # so this won't have any side-effects. But it will tell you if a PR
+  # completely broke oranda/mdbook. Sadly we don't provide previews (yet)!
+  pull_request:
+
+  # Whenever something gets pushed to main, update the docs!
+  # This is great for getting docs changes live without cutting a full release.
+  #
+  # Note that if you're using cargo-dist, this will "race" the Release workflow
+  # that actually builds the Github Release that oranda tries to read (and
+  # this will almost certainly complete first). As a result you will publish
+  # docs for the latest commit but the oranda landing page won't know about
+  # the latest release. The workflow_run trigger below will properly wait for
+  # cargo-dist, and so this half-published state will only last for ~10 minutes.
+  #
+  # If you only want docs to update with releases, disable this, or change it to
+  # a "release" branch. You can, of course, also manually trigger a workflow run
+  # when you want the docs to update.
+  push:
+    branches:
+      - main
+
+  # Whenever a workflow called "Release" completes, update the docs!
+  #
+  # If you're using cargo-dist, this is recommended, as it will ensure that
+  # oranda always sees the latest release right when it's available. Note
+  # however that Github's UI is wonky when you use workflow_run, and won't
+  # show this workflow as part of any commit. You have to go to the "actions"
+  # tab for your repo to see this one running (the gh-pages deploy will also
+  # only show up there).
+  workflow_run:
+    workflows: [ "Release" ]
+    types:
+      - completed
+
+# Alright, let's do it!
+jobs:
+  web:
+    name: Build and deploy site and docs
+    runs-on: ubuntu-latest
+    steps:
+      # Setup
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: swatinem/rust-cache@v2
+
+      # If you use any mdbook plugins, here's the place to install them!
+
+      # Install and run oranda (and mdbook)
+      # This will write all output to ./public/ (including copying mdbook's output to there)
+      - name: Install and run oranda
+        run: |
+          curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/oranda/releases/download/v0.3.1/oranda-installer.sh | sh
+          oranda build
+
+      # Deploy to our gh-pages branch (creating it if it doesn't exist)
+      # the "public" dir that oranda made above will become the root dir
+      # of this branch.
+      #
+      # Note that once the gh-pages branch exists, you must
+      # go into repo's settings > pages and set "deploy from branch: gh-pages"
+      # the other defaults work fine.
+      - name: Deploy to Github Pages
+        uses: JamesIves/github-pages-deploy-action@v4.4.1
+        # ONLY if we're on main (so no PRs or feature branches allowed!)
+        if: ${{ github.ref == 'refs/heads/main' }}
+        with:
+          branch: gh-pages
+          # Gotta tell the action where to find oranda's output
+          folder: public
+          token: ${{ secrets.GITHUB_TOKEN }}
+          single-commit: true

.gitignore

@@ -5,5 +5,14 @@ target/
 *.pdb
 exercises/clippy/Cargo.toml
 exercises/clippy/Cargo.lock
+rust-project.json
 .idea
-.vscode
+.vscode/*
+!.vscode/extensions.json
+*.iml
+*.o
+public/
+.direnv/
+
+# Local Netlify folder
+.netlify

.gitpod.yml

@@ -4,4 +4,4 @@ tasks:
 
 vscode:
   extensions:
-    - rust-lang.rust@0.7.8:CvNqMTgDdt3UXt+6BCDTVg==
+    - rust-lang.rust-analyzer@0.3.1348

.markdownlint.yml

@@ -0,0 +1,2 @@
+# MD013/line-length Line length, Expected: 80
+MD013: false

.replit

@@ -1,2 +0,0 @@
-language = "rust"
-run = "[ -x ~/.cargo/bin/rustlings ] && ~/.cargo/bin/rustlings watch || ./install.sh"

.vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+    "recommendations": [
+        "rust-lang.rust-analyzer"
+    ]
+}

AUTHORS.md

@@ -0,0 +1,356 @@
+## Authors
+
+This file lists the people that have contributed to this project.
+
+Excluded from this list are @carols10cents and @diannasoreil, the principal
+authors.
+
+<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
+<!-- prettier-ignore-start -->
+<!-- markdownlint-disable -->
+<table>
+  <tbody>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="http://carol-nichols.com"><img src="https://avatars2.githubusercontent.com/u/193874?v=4?s=100" width="100px;" alt="Carol (Nichols &#124;&#124; Goulding)"/><br /><sub><b>Carol (Nichols &#124;&#124; Goulding)</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=carols10cents" title="Code">💻</a> <a href="#content-carols10cents" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://twitter.com/QuietMisdreavus"><img src="https://avatars2.githubusercontent.com/u/5217170?v=4?s=100" width="100px;" alt="QuietMisdreavus"/><br /><sub><b>QuietMisdreavus</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=QuietMisdreavus" title="Code">💻</a> <a href="#content-QuietMisdreavus" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/robertlugg"><img src="https://avatars0.githubusercontent.com/u/6054540?v=4?s=100" width="100px;" alt="Robert M Lugg"/><br /><sub><b>Robert M Lugg</b></sub></a><br /><a href="#content-robertlugg" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://hynek.me/about/"><img src="https://avatars3.githubusercontent.com/u/41240?v=4?s=100" width="100px;" alt="Hynek Schlawack"/><br /><sub><b>Hynek Schlawack</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hynek" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://spacekookie.de"><img src="https://avatars0.githubusercontent.com/u/7669898?v=4?s=100" width="100px;" alt="Katharina Fey"/><br /><sub><b>Katharina Fey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=spacekookie" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/lukabavdaz"><img src="https://avatars0.githubusercontent.com/u/9624558?v=4?s=100" width="100px;" alt="lukabavdaz"/><br /><sub><b>lukabavdaz</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lukabavdaz" title="Code">💻</a> <a href="#content-lukabavdaz" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://vestera.as"><img src="https://avatars2.githubusercontent.com/u/4187449?v=4?s=100" width="100px;" alt="Erik Vesteraas"/><br /><sub><b>Erik Vesteraas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=evestera" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Delet0r"><img src="https://avatars1.githubusercontent.com/u/23195618?v=4?s=100" width="100px;" alt="delet0r"/><br /><sub><b>delet0r</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Delet0r" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="http://phinary.ca"><img src="https://avatars1.githubusercontent.com/u/10522375?v=4?s=100" width="100px;" alt="Shaun Bennett"/><br /><sub><b>Shaun Bennett</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=shaunbennett" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/abagshaw"><img src="https://avatars2.githubusercontent.com/u/8594541?v=4?s=100" width="100px;" alt="Andrew Bagshaw"/><br /><sub><b>Andrew Bagshaw</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abagshaw" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://ai6ua.net/"><img src="https://avatars2.githubusercontent.com/u/175578?v=4?s=100" width="100px;" alt="Kyle Isom"/><br /><sub><b>Kyle Isom</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kisom" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/ColinPitrat"><img src="https://avatars3.githubusercontent.com/u/1541863?v=4?s=100" width="100px;" alt="Colin Pitrat"/><br /><sub><b>Colin Pitrat</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ColinPitrat" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://zacanger.com"><img src="https://avatars3.githubusercontent.com/u/12520493?v=4?s=100" width="100px;" alt="Zac Anger"/><br /><sub><b>Zac Anger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=zacanger" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/mgeier"><img src="https://avatars1.githubusercontent.com/u/705404?v=4?s=100" width="100px;" alt="Matthias Geier"/><br /><sub><b>Matthias Geier</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=mgeier" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/cjpearce"><img src="https://avatars1.githubusercontent.com/u/3453268?v=4?s=100" width="100px;" alt="Chris Pearce"/><br /><sub><b>Chris Pearce</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cjpearce" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://yvan-sraka.github.io"><img src="https://avatars2.githubusercontent.com/u/705213?v=4?s=100" width="100px;" alt="Yvan Sraka"/><br /><sub><b>Yvan Sraka</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=yvan-sraka" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/dendi239"><img src="https://avatars3.githubusercontent.com/u/16478650?v=4?s=100" width="100px;" alt="Denys Smirnov"/><br /><sub><b>Denys Smirnov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=dendi239" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/eddyp"><img src="https://avatars2.githubusercontent.com/u/123772?v=4?s=100" width="100px;" alt="eddyp"/><br /><sub><b>eddyp</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=eddyp" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://about.me/BrianKung"><img src="https://avatars1.githubusercontent.com/u/2836167?v=4?s=100" width="100px;" alt="Brian Kung"/><br /><sub><b>Brian Kung</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=briankung" title="Code">💻</a> <a href="#content-briankung" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://rcousineau.gitlab.io"><img src="https://avatars3.githubusercontent.com/u/281039?v=4?s=100" width="100px;" alt="Russell"/><br /><sub><b>Russell</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=miller-time" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://danwilhelm.com"><img src="https://avatars3.githubusercontent.com/u/6137185?v=4?s=100" width="100px;" alt="Dan Wilhelm"/><br /><sub><b>Dan Wilhelm</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=danwilhelm" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Jesse-Cameron"><img src="https://avatars3.githubusercontent.com/u/3723654?v=4?s=100" width="100px;" alt="Jesse"/><br /><sub><b>Jesse</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Jesse-Cameron" title="Code">💻</a> <a href="#content-Jesse-Cameron" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/MrFroop"><img src="https://avatars3.githubusercontent.com/u/196700?v=4?s=100" width="100px;" alt="Fredrik Jambrén"/><br /><sub><b>Fredrik Jambrén</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MrFroop" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/petemcfarlane"><img src="https://avatars3.githubusercontent.com/u/3472717?v=4?s=100" width="100px;" alt="Pete McFarlane"/><br /><sub><b>Pete McFarlane</b></sub></a><br /><a href="#content-petemcfarlane" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/nkanderson"><img src="https://avatars0.githubusercontent.com/u/4128825?v=4?s=100" width="100px;" alt="nkanderson"/><br /><sub><b>nkanderson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nkanderson" title="Code">💻</a> <a href="#content-nkanderson" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/ajaxm"><img src="https://avatars0.githubusercontent.com/u/13360138?v=4?s=100" width="100px;" alt="Ajax M"/><br /><sub><b>Ajax M</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ajaxm" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://dylnuge.com"><img src="https://avatars2.githubusercontent.com/u/118624?v=4?s=100" width="100px;" alt="Dylan Nugent"/><br /><sub><b>Dylan Nugent</b></sub></a><br /><a href="#content-Dylnuge" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/vyaslav"><img src="https://avatars0.githubusercontent.com/u/1385427?v=4?s=100" width="100px;" alt="vyaslav"/><br /><sub><b>vyaslav</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=vyaslav" title="Code">💻</a> <a href="#content-vyaslav" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://join.sfxd.org"><img src="https://avatars1.githubusercontent.com/u/17297466?v=4?s=100" width="100px;" alt="George"/><br /><sub><b>George</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=gdoenlen" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/nyxtom"><img src="https://avatars2.githubusercontent.com/u/222763?v=4?s=100" width="100px;" alt="Thomas Holloway"/><br /><sub><b>Thomas Holloway</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nyxtom" title="Code">💻</a> <a href="#content-nyxtom" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/workingjubilee"><img src="https://avatars1.githubusercontent.com/u/46493976?v=4?s=100" width="100px;" alt="Jubilee"/><br /><sub><b>Jubilee</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=workingjubilee" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/WofWca"><img src="https://avatars1.githubusercontent.com/u/39462442?v=4?s=100" width="100px;" alt="WofWca"/><br /><sub><b>WofWca</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=WofWca" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/jrvidal"><img src="https://avatars0.githubusercontent.com/u/1636604?v=4?s=100" width="100px;" alt="Roberto Vidal"/><br /><sub><b>Roberto Vidal</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Documentation">📖</a> <a href="#ideas-jrvidal" title="Ideas, Planning, & Feedback">🤔</a> <a href="#maintenance-jrvidal" title="Maintenance">🚧</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/jensim"><img src="https://avatars0.githubusercontent.com/u/3663856?v=4?s=100" width="100px;" alt="Jens"/><br /><sub><b>Jens</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jensim" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://rahatah.me/d"><img src="https://avatars3.githubusercontent.com/u/3174006?v=4?s=100" width="100px;" alt="Rahat Ahmed"/><br /><sub><b>Rahat Ahmed</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=rahatarmanahmed" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/AbdouSeck"><img src="https://avatars2.githubusercontent.com/u/6490055?v=4?s=100" width="100px;" alt="Abdou Seck"/><br /><sub><b>Abdou Seck</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=AbdouSeck" title="Code">💻</a> <a href="#content-AbdouSeck" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAbdouSeck" title="Reviewed Pull Requests">👀</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://codehearts.com"><img src="https://avatars0.githubusercontent.com/u/2885412?v=4?s=100" width="100px;" alt="Katie"/><br /><sub><b>Katie</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=codehearts" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Socratides"><img src="https://avatars3.githubusercontent.com/u/27732983?v=4?s=100" width="100px;" alt="Socrates"/><br /><sub><b>Socrates</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Socratides" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/gnodarse"><img src="https://avatars3.githubusercontent.com/u/46761795?v=4?s=100" width="100px;" alt="gnodarse"/><br /><sub><b>gnodarse</b></sub></a><br /><a href="#content-gnodarse" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/harrisonmetz"><img src="https://avatars1.githubusercontent.com/u/7883408?v=4?s=100" width="100px;" alt="Harrison Metzger"/><br /><sub><b>Harrison Metzger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=harrisonmetz" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/TorbenJ"><img src="https://avatars2.githubusercontent.com/u/9077102?v=4?s=100" width="100px;" alt="Torben Jonas"/><br /><sub><b>Torben Jonas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=TorbenJ" title="Code">💻</a> <a href="#content-TorbenJ" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://paulbissex.com/"><img src="https://avatars0.githubusercontent.com/u/641?v=4?s=100" width="100px;" alt="Paul Bissex"/><br /><sub><b>Paul Bissex</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=pbx" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/sjmann"><img src="https://avatars0.githubusercontent.com/u/6589896?v=4?s=100" width="100px;" alt="Steven Mann"/><br /><sub><b>Steven Mann</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sjmann" title="Code">💻</a> <a href="#content-sjmann" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://smmdb.net/"><img src="https://avatars2.githubusercontent.com/u/5855071?v=4?s=100" width="100px;" alt="Mario Reder"/><br /><sub><b>Mario Reder</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Tarnadas" title="Code">💻</a> <a href="#content-Tarnadas" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://keybase.io/skim"><img src="https://avatars0.githubusercontent.com/u/47347?v=4?s=100" width="100px;" alt="skim"/><br /><sub><b>skim</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sl4m" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/sanjaykdragon"><img src="https://avatars1.githubusercontent.com/u/10261698?v=4?s=100" width="100px;" alt="Sanjay K"/><br /><sub><b>Sanjay K</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sanjaykdragon" title="Code">💻</a> <a href="#content-sanjaykdragon" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://www.rohanjain.in"><img src="https://avatars1.githubusercontent.com/u/343499?v=4?s=100" width="100px;" alt="Rohan Jain"/><br /><sub><b>Rohan Jain</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=crodjer" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.saidaspen.se"><img src="https://avatars1.githubusercontent.com/u/7727687?v=4?s=100" width="100px;" alt="Said Aspen"/><br /><sub><b>Said Aspen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=saidaspen" title="Code">💻</a> <a href="#content-saidaspen" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/uce"><img src="https://avatars3.githubusercontent.com/u/1756620?v=4?s=100" width="100px;" alt="Ufuk Celebi"/><br /><sub><b>Ufuk Celebi</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=uce" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/lebedevsergey"><img src="https://avatars2.githubusercontent.com/u/7325764?v=4?s=100" width="100px;" alt="lebedevsergey"/><br /><sub><b>lebedevsergey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lebedevsergey" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/avrong"><img src="https://avatars2.githubusercontent.com/u/6342851?v=4?s=100" width="100px;" alt="Aleksei Trifonov"/><br /><sub><b>Aleksei Trifonov</b></sub></a><br /><a href="#content-avrong" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://drn.ie"><img src="https://avatars2.githubusercontent.com/u/411136?v=4?s=100" width="100px;" alt="Darren Meehan"/><br /><sub><b>Darren Meehan</b></sub></a><br /><a href="#content-Darrenmeehan" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/jihchi"><img src="https://avatars1.githubusercontent.com/u/87983?v=4?s=100" width="100px;" alt="Jihchi Lee"/><br /><sub><b>Jihchi Lee</b></sub></a><br /><a href="#content-jihchi" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/bertonha"><img src="https://avatars3.githubusercontent.com/u/1225902?v=4?s=100" width="100px;" alt="Christofer Bertonha"/><br /><sub><b>Christofer Bertonha</b></sub></a><br /><a href="#content-bertonha" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/apatniv"><img src="https://avatars2.githubusercontent.com/u/22565917?v=4?s=100" width="100px;" alt="Vivek Bharath Akupatni"/><br /><sub><b>Vivek Bharath Akupatni</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Tests">⚠️</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/DiD92"><img src="https://avatars3.githubusercontent.com/u/6002416?v=4?s=100" width="100px;" alt="Dídac Sementé Fernández"/><br /><sub><b>Dídac Sementé Fernández</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=DiD92" title="Code">💻</a> <a href="#content-DiD92" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/wrobstory"><img src="https://avatars3.githubusercontent.com/u/2601457?v=4?s=100" width="100px;" alt="Rob Story"/><br /><sub><b>Rob Story</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=wrobstory" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/siobhanjacobson"><img src="https://avatars2.githubusercontent.com/u/28983835?v=4?s=100" width="100px;" alt="Siobhan Jacobson"/><br /><sub><b>Siobhan Jacobson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=siobhanjacobson" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.linkedin.com/in/evancarroll/"><img src="https://avatars2.githubusercontent.com/u/19922?v=4?s=100" width="100px;" alt="Evan Carroll"/><br /><sub><b>Evan Carroll</b></sub></a><br /><a href="#content-EvanCarroll" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://www.jawaadmahmood.com"><img src="https://avatars3.githubusercontent.com/u/95606?v=4?s=100" width="100px;" alt="Jawaad Mahmood"/><br /><sub><b>Jawaad Mahmood</b></sub></a><br /><a href="#content-jmahmood" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/GaurangTandon"><img src="https://avatars1.githubusercontent.com/u/6308683?v=4?s=100" width="100px;" alt="Gaurang Tandon"/><br /><sub><b>Gaurang Tandon</b></sub></a><br /><a href="#content-GaurangTandon" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/dev-cyprium"><img src="https://avatars1.githubusercontent.com/u/6002628?v=4?s=100" width="100px;" alt="Stefan Kupresak"/><br /><sub><b>Stefan Kupresak</b></sub></a><br /><a href="#content-dev-cyprium" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/greg-el"><img src="https://avatars3.githubusercontent.com/u/45019882?v=4?s=100" width="100px;" alt="Greg Leonard"/><br /><sub><b>Greg Leonard</b></sub></a><br /><a href="#content-greg-el" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://ryanpcmcquen.org"><img src="https://avatars3.githubusercontent.com/u/772937?v=4?s=100" width="100px;" alt="Ryan McQuen"/><br /><sub><b>Ryan McQuen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ryanpcmcquen" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/AnnikaCodes"><img src="https://avatars3.githubusercontent.com/u/56906084?v=4?s=100" width="100px;" alt="Annika"/><br /><sub><b>Annika</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAnnikaCodes" title="Reviewed Pull Requests">👀</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://darnuria.eu"><img src="https://avatars1.githubusercontent.com/u/2827553?v=4?s=100" width="100px;" alt="Axel Viala"/><br /><sub><b>Axel Viala</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=darnuria" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://sazid.github.io"><img src="https://avatars1.githubusercontent.com/u/2370167?v=4?s=100" width="100px;" alt="Mohammed Sazid Al Rashid"/><br /><sub><b>Mohammed Sazid Al Rashid</b></sub></a><br /><a href="#content-sazid" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=sazid" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://codingthemsoftly.com"><img src="https://avatars1.githubusercontent.com/u/17479099?v=4?s=100" width="100px;" alt="Caleb Webber"/><br /><sub><b>Caleb Webber</b></sub></a><br /><a href="#maintenance-seeplusplus" title="Maintenance">🚧</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/pcn"><img src="https://avatars2.githubusercontent.com/u/1056756?v=4?s=100" width="100px;" alt="Peter N"/><br /><sub><b>Peter N</b></sub></a><br /><a href="#maintenance-pcn" title="Maintenance">🚧</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/seancad"><img src="https://avatars1.githubusercontent.com/u/47405611?v=4?s=100" width="100px;" alt="seancad"/><br /><sub><b>seancad</b></sub></a><br /><a href="#maintenance-seancad" title="Maintenance">🚧</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://willhayworth.com"><img src="https://avatars3.githubusercontent.com/u/181174?v=4?s=100" width="100px;" alt="Will Hayworth"/><br /><sub><b>Will Hayworth</b></sub></a><br /><a href="#content-wsh" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/chrizel"><img src="https://avatars3.githubusercontent.com/u/20802?v=4?s=100" width="100px;" alt="Christian Zeller"/><br /><sub><b>Christian Zeller</b></sub></a><br /><a href="#content-chrizel" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/jfchevrette"><img src="https://avatars.githubusercontent.com/u/3001?v=4?s=100" width="100px;" alt="Jean-Francois Chevrette"/><br /><sub><b>Jean-Francois Chevrette</b></sub></a><br /><a href="#content-jfchevrette" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=jfchevrette" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/jbaber"><img src="https://avatars.githubusercontent.com/u/1908117?v=4?s=100" width="100px;" alt="John Baber-Lucero"/><br /><sub><b>John Baber-Lucero</b></sub></a><br /><a href="#content-jbaber" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/tal-zvon"><img src="https://avatars.githubusercontent.com/u/3195851?v=4?s=100" width="100px;" alt="Tal"/><br /><sub><b>Tal</b></sub></a><br /><a href="#content-tal-zvon" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/apogeeoak"><img src="https://avatars.githubusercontent.com/u/59737221?v=4?s=100" width="100px;" alt="apogeeoak"/><br /><sub><b>apogeeoak</b></sub></a><br /><a href="#content-apogeeoak" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=apogeeoak" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://www.garfieldtech.com/"><img src="https://avatars.githubusercontent.com/u/254863?v=4?s=100" width="100px;" alt="Larry Garfield"/><br /><sub><b>Larry Garfield</b></sub></a><br /><a href="#content-Crell" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/circumspect"><img src="https://avatars.githubusercontent.com/u/40770208?v=4?s=100" width="100px;" alt="circumspect"/><br /><sub><b>circumspect</b></sub></a><br /><a href="#content-circumspect" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/cjwyett"><img src="https://avatars.githubusercontent.com/u/34195737?v=4?s=100" width="100px;" alt="Cyrus Wyett"/><br /><sub><b>Cyrus Wyett</b></sub></a><br /><a href="#content-cjwyett" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/cadolphs"><img src="https://avatars.githubusercontent.com/u/13894820?v=4?s=100" width="100px;" alt="cadolphs"/><br /><sub><b>cadolphs</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cadolphs" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.haveneer.com"><img src="https://avatars.githubusercontent.com/u/26146722?v=4?s=100" width="100px;" alt="Pascal H."/><br /><sub><b>Pascal H.</b></sub></a><br /><a href="#content-hpwxf" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://twitter.com/chapeupreto"><img src="https://avatars.githubusercontent.com/u/834048?v=4?s=100" width="100px;" alt="Rod Elias"/><br /><sub><b>Rod Elias</b></sub></a><br /><a href="#content-chapeupreto" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/blerchy"><img src="https://avatars.githubusercontent.com/u/2555355?v=4?s=100" width="100px;" alt="Matt Lebl"/><br /><sub><b>Matt Lebl</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=blerchy" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://flakolefluk.dev"><img src="https://avatars.githubusercontent.com/u/11986564?v=4?s=100" width="100px;" alt="Ignacio Le Fluk"/><br /><sub><b>Ignacio Le Fluk</b></sub></a><br /><a href="#content-flakolefluk" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/tlyu"><img src="https://avatars.githubusercontent.com/u/431873?v=4?s=100" width="100px;" alt="Taylor Yu"/><br /><sub><b>Taylor Yu</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=tlyu" title="Code">💻</a> <a href="#content-tlyu" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://zerotask.github.io"><img src="https://avatars.githubusercontent.com/u/20150243?v=4?s=100" width="100px;" alt="Patrick Hintermayer"/><br /><sub><b>Patrick Hintermayer</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Zerotask" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://petkopavlovski.com/"><img src="https://avatars.githubusercontent.com/u/32264020?v=4?s=100" width="100px;" alt="Pete Pavlovski"/><br /><sub><b>Pete Pavlovski</b></sub></a><br /><a href="#content-arthas168" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/k12ish"><img src="https://avatars.githubusercontent.com/u/45272873?v=4?s=100" width="100px;" alt="k12ish"/><br /><sub><b>k12ish</b></sub></a><br /><a href="#content-k12ish" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/hongshaoyang"><img src="https://avatars.githubusercontent.com/u/19281800?v=4?s=100" width="100px;" alt="Shao Yang Hong"/><br /><sub><b>Shao Yang Hong</b></sub></a><br /><a href="#content-hongshaoyang" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/bmacer"><img src="https://avatars.githubusercontent.com/u/13931806?v=4?s=100" width="100px;" alt="Brandon Macer"/><br /><sub><b>Brandon Macer</b></sub></a><br /><a href="#content-bmacer" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/stoiandan"><img src="https://avatars.githubusercontent.com/u/10388612?v=4?s=100" width="100px;" alt="Stoian Dan"/><br /><sub><b>Stoian Dan</b></sub></a><br /><a href="#content-stoiandan" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://about.me/pjdelport"><img src="https://avatars.githubusercontent.com/u/630271?v=4?s=100" width="100px;" alt="Pi Delport"/><br /><sub><b>Pi Delport</b></sub></a><br /><a href="#content-PiDelport" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/sateeshkumarb"><img src="https://avatars.githubusercontent.com/u/429263?v=4?s=100" width="100px;" alt="Sateesh "/><br /><sub><b>Sateesh </b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sateeshkumarb" title="Code">💻</a> <a href="#content-sateeshkumarb" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/kayuapi"><img src="https://avatars.githubusercontent.com/u/10304328?v=4?s=100" width="100px;" alt="ZC"/><br /><sub><b>ZC</b></sub></a><br /><a href="#content-kayuapi" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/hyperparabolic"><img src="https://avatars.githubusercontent.com/u/12348474?v=4?s=100" width="100px;" alt="hyperparabolic"/><br /><sub><b>hyperparabolic</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hyperparabolic" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.net4visions.at"><img src="https://avatars.githubusercontent.com/u/5228369?v=4?s=100" width="100px;" alt="arlecchino"/><br /><sub><b>arlecchino</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kolbma" title="Documentation">📖</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://richthofen.io/"><img src="https://avatars.githubusercontent.com/u/7576730?v=4?s=100" width="100px;" alt="Richthofen"/><br /><sub><b>Richthofen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jazzplato" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/cseltol"><img src="https://avatars.githubusercontent.com/u/64264529?v=4?s=100" width="100px;" alt="Ivan Nerazumov"/><br /><sub><b>Ivan Nerazumov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cseltol" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/lauralindzey"><img src="https://avatars.githubusercontent.com/u/65185744?v=4?s=100" width="100px;" alt="lauralindzey"/><br /><sub><b>lauralindzey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lauralindzey" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/sinharaksh1t"><img src="https://avatars.githubusercontent.com/u/28585848?v=4?s=100" width="100px;" alt="Rakshit Sinha"/><br /><sub><b>Rakshit Sinha</b></sub></a><br /><a href="#content-sinharaksh1t" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/dbednar230"><img src="https://avatars.githubusercontent.com/u/54457902?v=4?s=100" width="100px;" alt="Damian"/><br /><sub><b>Damian</b></sub></a><br /><a href="#content-dbednar230" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://benarmstead.co.uk"><img src="https://avatars.githubusercontent.com/u/70973680?v=4?s=100" width="100px;" alt="Ben Armstead"/><br /><sub><b>Ben Armstead</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=benarmstead" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/anuk909"><img src="https://avatars.githubusercontent.com/u/34924662?v=4?s=100" width="100px;" alt="anuk909"/><br /><sub><b>anuk909</b></sub></a><br /><a href="#content-anuk909" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=anuk909" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://granddaifuku.com/"><img src="https://avatars.githubusercontent.com/u/49578068?v=4?s=100" width="100px;" alt="granddaifuku"/><br /><sub><b>granddaifuku</b></sub></a><br /><a href="#content-granddaifuku" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://weilet.me"><img src="https://avatars.githubusercontent.com/u/32561597?v=4?s=100" width="100px;" alt="Weilet"/><br /><sub><b>Weilet</b></sub></a><br /><a href="#content-Weilet" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Millione"><img src="https://avatars.githubusercontent.com/u/38575932?v=4?s=100" width="100px;" alt="LIU JIE"/><br /><sub><b>LIU JIE</b></sub></a><br /><a href="#content-Millione" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/abusch"><img src="https://avatars.githubusercontent.com/u/506344?v=4?s=100" width="100px;" alt="Antoine Büsch"/><br /><sub><b>Antoine Büsch</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abusch" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://frogtd.com/"><img src="https://avatars.githubusercontent.com/u/31412003?v=4?s=100" width="100px;" alt="frogtd"/><br /><sub><b>frogtd</b></sub></a><br /><a href="#content-frogtd" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/EmisonLu"><img src="https://avatars.githubusercontent.com/u/54395432?v=4?s=100" width="100px;" alt="Zhenghao Lu"/><br /><sub><b>Zhenghao Lu</b></sub></a><br /><a href="#content-EmisonLu" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://soundtrackyourbrand.com"><img src="https://avatars.githubusercontent.com/u/762956?v=4?s=100" width="100px;" alt="Fredrik Enestad"/><br /><sub><b>Fredrik Enestad</b></sub></a><br /><a href="#content-fredr" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://xuesong.pydevops.com"><img src="https://avatars.githubusercontent.com/u/18476085?v=4?s=100" width="100px;" alt="xuesong"/><br /><sub><b>xuesong</b></sub></a><br /><a href="#content-xuesongbj" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/MpdWalsh"><img src="https://avatars.githubusercontent.com/u/48160144?v=4?s=100" width="100px;" alt="Michael Walsh"/><br /><sub><b>Michael Walsh</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MpdWalsh" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/alirezaghey"><img src="https://avatars.githubusercontent.com/u/26653424?v=4?s=100" width="100px;" alt="alirezaghey"/><br /><sub><b>alirezaghey</b></sub></a><br /><a href="#content-alirezaghey" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/frvannes16"><img src="https://avatars.githubusercontent.com/u/3188475?v=4?s=100" width="100px;" alt="Franklin van Nes"/><br /><sub><b>Franklin van Nes</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=frvannes16" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://nekonako.github.io"><img src="https://avatars.githubusercontent.com/u/46141275?v=4?s=100" width="100px;" alt="nekonako"/><br /><sub><b>nekonako</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nekonako" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/tan-zx"><img src="https://avatars.githubusercontent.com/u/67887489?v=4?s=100" width="100px;" alt="ZX"/><br /><sub><b>ZX</b></sub></a><br /><a href="#content-tan-zx" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/sundevilyang"><img src="https://avatars.githubusercontent.com/u/1499214?v=4?s=100" width="100px;" alt="Yang Wen"/><br /><sub><b>Yang Wen</b></sub></a><br /><a href="#content-sundevilyang" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://brandon-high.com"><img src="https://avatars.githubusercontent.com/u/759848?v=4?s=100" width="100px;" alt="Brandon High"/><br /><sub><b>Brandon High</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=highb" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/x-hgg-x"><img src="https://avatars.githubusercontent.com/u/39058530?v=4?s=100" width="100px;" alt="x-hgg-x"/><br /><sub><b>x-hgg-x</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=x-hgg-x" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://kisaragieffective.github.io"><img src="https://avatars.githubusercontent.com/u/48310258?v=4?s=100" width="100px;" alt="Kisaragi"/><br /><sub><b>Kisaragi</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=KisaragiEffective" title="Documentation">📖</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Kallu-A"><img src="https://avatars.githubusercontent.com/u/73198738?v=4?s=100" width="100px;" alt="Lucas Aries"/><br /><sub><b>Lucas Aries</b></sub></a><br /><a href="#content-Kallu-A" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/ragreenburg"><img src="https://avatars.githubusercontent.com/u/24358100?v=4?s=100" width="100px;" alt="ragreenburg"/><br /><sub><b>ragreenburg</b></sub></a><br /><a href="#content-ragreenburg" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/stevenfukase"><img src="https://avatars.githubusercontent.com/u/66785624?v=4?s=100" width="100px;" alt="stevenfukase"/><br /><sub><b>stevenfukase</b></sub></a><br /><a href="#content-stevenfukase" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/J-S-Kim"><img src="https://avatars.githubusercontent.com/u/17569303?v=4?s=100" width="100px;" alt="J-S-Kim"/><br /><sub><b>J-S-Kim</b></sub></a><br /><a href="#content-J-S-Kim" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Fointard"><img src="https://avatars.githubusercontent.com/u/9333398?v=4?s=100" width="100px;" alt="Fointard"/><br /><sub><b>Fointard</b></sub></a><br /><a href="#content-Fointard" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/rytheo"><img src="https://avatars.githubusercontent.com/u/22184325?v=4?s=100" width="100px;" alt="Ryan Lowe"/><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" valign="top" width="12.5%"><a href="http://www.dashen.tech"><img src="https://avatars.githubusercontent.com/u/15921519?v=4?s=100" width="100px;" alt="cui fliter"/><br /><sub><b>cui fliter</b></sub></a><br /><a href="#content-cuishuang" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/luskwater"><img src="https://avatars.githubusercontent.com/u/42529?v=4?s=100" width="100px;" alt="Ron Lusk"/><br /><sub><b>Ron Lusk</b></sub></a><br /><a href="#content-luskwater" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="http://liby.github.io/liby/"><img src="https://avatars.githubusercontent.com/u/38807139?v=4?s=100" width="100px;" alt="Bryan Lee"/><br /><sub><b>Bryan Lee</b></sub></a><br /><a href="#content-liby" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://nandaja.space"><img src="https://avatars.githubusercontent.com/u/2624550?v=4?s=100" width="100px;" alt="Nandaja Varma"/><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" valign="top" width="12.5%"><a href="https://github.com/merelymyself"><img src="https://avatars.githubusercontent.com/u/88221256?v=4?s=100" width="100px;" alt="pwygab"/><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" valign="top" width="12.5%"><a href="http://linkedin.com/in/lucasgrvarela"><img src="https://avatars.githubusercontent.com/u/37870368?v=4?s=100" width="100px;" alt="Lucas Grigolon Varela"/><br /><sub><b>Lucas Grigolon Varela</b></sub></a><br /><a href="#content-lucasgrvarela" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/bufo24"><img src="https://avatars.githubusercontent.com/u/32884105?v=4?s=100" width="100px;" alt="Bufo"/><br /><sub><b>Bufo</b></sub></a><br /><a href="#content-bufo24" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://rustnote.com"><img src="https://avatars.githubusercontent.com/u/77730378?v=4?s=100" width="100px;" alt="Jack Clayton"/><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" valign="top" width="12.5%"><a href="https://github.com/klkl0808"><img src="https://avatars.githubusercontent.com/u/24694249?v=4?s=100" width="100px;" alt="Konstantin"/><br /><sub><b>Konstantin</b></sub></a><br /><a href="#content-klkl0808" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/0pling"><img src="https://avatars.githubusercontent.com/u/104090344?v=4?s=100" width="100px;" alt="0pling"/><br /><sub><b>0pling</b></sub></a><br /><a href="#content-0pling" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/KatanaFluorescent"><img src="https://avatars.githubusercontent.com/u/60199077?v=4?s=100" width="100px;" alt="KatanaFluorescent"/><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" valign="top" width="12.5%"><a href="https://github.com/Drew-Morris"><img src="https://avatars.githubusercontent.com/u/95818166?v=4?s=100" width="100px;" alt="Drew Morris"/><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" valign="top" width="12.5%"><a href="https://github.com/camperdue42"><img src="https://avatars.githubusercontent.com/u/43047763?v=4?s=100" width="100px;" alt="camperdue42"/><br /><sub><b>camperdue42</b></sub></a><br /><a href="#content-camperdue42" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/YsuOS"><img src="https://avatars.githubusercontent.com/u/30138661?v=4?s=100" width="100px;" alt="YsuOS"/><br /><sub><b>YsuOS</b></sub></a><br /><a href="#content-YsuOS" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://lichess.org/@/StevenEmily"><img src="https://avatars.githubusercontent.com/u/58114641?v=4?s=100" width="100px;" alt="Steven Nguyen"/><br /><sub><b>Steven Nguyen</b></sub></a><br /><a href="#content-icecream17" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://noahcairns.dev"><img src="https://avatars.githubusercontent.com/u/94420090?v=4?s=100" width="100px;" alt="nacairns1"/><br /><sub><b>nacairns1</b></sub></a><br /><a href="#content-nacairns1" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/pgjbz"><img src="https://avatars.githubusercontent.com/u/22059237?v=4?s=100" width="100px;" alt="Paulo Gabriel Justino Bezerra"/><br /><sub><b>Paulo Gabriel Justino Bezerra</b></sub></a><br /><a href="#content-pgjbz" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/jaystile"><img src="https://avatars.githubusercontent.com/u/46078028?v=4?s=100" width="100px;" alt="Jason"/><br /><sub><b>Jason</b></sub></a><br /><a href="#content-jaystile" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://exdx.github.io"><img src="https://avatars.githubusercontent.com/u/31546601?v=4?s=100" width="100px;" alt="exdx"/><br /><sub><b>exdx</b></sub></a><br /><a href="#content-exdx" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Jzow"><img src="https://avatars.githubusercontent.com/u/68860495?v=4?s=100" width="100px;" alt="James Zow"/><br /><sub><b>James Zow</b></sub></a><br /><a href="#content-Jzow" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://jamesabromley.wordpress.com/"><img src="https://avatars.githubusercontent.com/u/2474334?v=4?s=100" width="100px;" alt="James Bromley"/><br /><sub><b>James Bromley</b></sub></a><br /><a href="#content-jayber" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/swhiteCQC"><img src="https://avatars.githubusercontent.com/u/77438466?v=4?s=100" width="100px;" alt="swhiteCQC"/><br /><sub><b>swhiteCQC</b></sub></a><br /><a href="#content-swhiteCQC" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/neilpate"><img src="https://avatars.githubusercontent.com/u/7802334?v=4?s=100" width="100px;" alt="Neil Pate"/><br /><sub><b>Neil Pate</b></sub></a><br /><a href="#content-neilpate" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://wojexe.com"><img src="https://avatars.githubusercontent.com/u/21208490?v=4?s=100" width="100px;" alt="wojexe"/><br /><sub><b>wojexe</b></sub></a><br /><a href="#content-wojexe" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Tostapunk"><img src="https://avatars.githubusercontent.com/u/25140297?v=4?s=100" width="100px;" alt="Mattia Schiavon"/><br /><sub><b>Mattia Schiavon</b></sub></a><br /><a href="#content-Tostapunk" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://toucantoco.com"><img src="https://avatars.githubusercontent.com/u/18406791?v=4?s=100" width="100px;" alt="Eric Jolibois"/><br /><sub><b>Eric Jolibois</b></sub></a><br /><a href="#content-PrettyWood" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="http://edwinchang.vercel.app"><img src="https://avatars.githubusercontent.com/u/88263098?v=4?s=100" width="100px;" alt="Edwin Chang"/><br /><sub><b>Edwin Chang</b></sub></a><br /><a href="#content-EdwinChang24" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://saikat.dev/"><img src="https://avatars.githubusercontent.com/u/7412443?v=4?s=100" width="100px;" alt="Saikat Das"/><br /><sub><b>Saikat Das</b></sub></a><br /><a href="#content-saikatdas0790" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/thatlittleboy"><img src="https://avatars.githubusercontent.com/u/30731072?v=4?s=100" width="100px;" alt="Jeremy Goh"/><br /><sub><b>Jeremy Goh</b></sub></a><br /><a href="#content-thatlittleboy" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Lioness100"><img src="https://avatars.githubusercontent.com/u/65814829?v=4?s=100" width="100px;" alt="Lioness100"/><br /><sub><b>Lioness100</b></sub></a><br /><a href="#content-Lioness100" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/tvkn"><img src="https://avatars.githubusercontent.com/u/79277926?v=4?s=100" width="100px;" alt="Tristan Nicholls"/><br /><sub><b>Tristan Nicholls</b></sub></a><br /><a href="#content-tvkn" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://clairewang.net"><img src="https://avatars.githubusercontent.com/u/9344258?v=4?s=100" width="100px;" alt="Claire"/><br /><sub><b>Claire</b></sub></a><br /><a href="#content-clairew" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Mouwrice"><img src="https://avatars.githubusercontent.com/u/56763273?v=4?s=100" width="100px;" alt="Maurice Van Wassenhove"/><br /><sub><b>Maurice Van Wassenhove</b></sub></a><br /><a href="#content-Mouwrice" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://jmthree.com"><img src="https://avatars.githubusercontent.com/u/77524?v=4?s=100" width="100px;" alt="John Mendelewski"/><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" valign="top" width="12.5%"><a href="http://fakhoury.xyz"><img src="https://avatars.githubusercontent.com/u/20828724?v=4?s=100" width="100px;" alt="Brian Fakhoury"/><br /><sub><b>Brian Fakhoury</b></sub></a><br /><a href="#content-brianfakhoury" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/markusboehme"><img src="https://avatars.githubusercontent.com/u/5074759?v=4?s=100" width="100px;" alt="Markus Boehme"/><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" valign="top" width="12.5%"><a href="https://github.com/nico-vromans"><img src="https://avatars.githubusercontent.com/u/48183857?v=4?s=100" width="100px;" alt="Nico Vromans"/><br /><sub><b>Nico Vromans</b></sub></a><br /><a href="#content-nico-vromans" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/vostok92"><img src="https://avatars.githubusercontent.com/u/540339?v=4?s=100" width="100px;" alt="vostok92"/><br /><sub><b>vostok92</b></sub></a><br /><a href="#content-vostok92" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://magnusrodseth.vercel.app"><img src="https://avatars.githubusercontent.com/u/59113973?v=4?s=100" width="100px;" alt="Magnus Rødseth"/><br /><sub><b>Magnus Rødseth</b></sub></a><br /><a href="#content-magnusrodseth" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/rubiesonthesky"><img src="https://avatars.githubusercontent.com/u/2591240?v=4?s=100" width="100px;" alt="rubiesonthesky"/><br /><sub><b>rubiesonthesky</b></sub></a><br /><a href="#content-rubiesonthesky" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://www.gabrielbianconi.com/"><img src="https://avatars.githubusercontent.com/u/1275491?v=4?s=100" width="100px;" alt="Gabriel Bianconi"/><br /><sub><b>Gabriel Bianconi</b></sub></a><br /><a href="#content-GabrielBianconi" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Kodylow"><img src="https://avatars.githubusercontent.com/u/74332828?v=4?s=100" width="100px;" alt="Kody Low"/><br /><sub><b>Kody Low</b></sub></a><br /><a href="#content-Kodylow" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/rzrymiak"><img src="https://avatars.githubusercontent.com/u/106121613?v=4?s=100" width="100px;" alt="rzrymiak"/><br /><sub><b>rzrymiak</b></sub></a><br /><a href="#content-rzrymiak" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/miguelraz"><img src="https://avatars.githubusercontent.com/u/13056181?v=4?s=100" width="100px;" alt="Miguel Raz Guzmán Macedo"/><br /><sub><b>Miguel Raz Guzmán Macedo</b></sub></a><br /><a href="#content-miguelraz" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/memark"><img src="https://avatars.githubusercontent.com/u/318504?v=4?s=100" width="100px;" alt="Magnus Markling"/><br /><sub><b>Magnus Markling</b></sub></a><br /><a href="#content-memark" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/gasparitiago"><img src="https://avatars.githubusercontent.com/u/3237254?v=4?s=100" width="100px;" alt="Tiago De Gaspari"/><br /><sub><b>Tiago De Gaspari</b></sub></a><br /><a href="#content-gasparitiago" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/skaunov"><img src="https://avatars.githubusercontent.com/u/65976143?v=4?s=100" width="100px;" alt="skaunov"/><br /><sub><b>skaunov</b></sub></a><br /><a href="#content-skaunov" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://caljacobson.dev"><img src="https://avatars.githubusercontent.com/u/9152032?v=4?s=100" width="100px;" alt="Cal Jacobson"/><br /><sub><b>Cal Jacobson</b></sub></a><br /><a href="#content-cj81499" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/duchonic"><img src="https://avatars.githubusercontent.com/u/34117620?v=4?s=100" width="100px;" alt="Duchoud Nicolas"/><br /><sub><b>Duchoud Nicolas</b></sub></a><br /><a href="#content-duchonic" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/gfaugere"><img src="https://avatars.githubusercontent.com/u/11901979?v=4?s=100" width="100px;" alt="Gaëtan Faugère"/><br /><sub><b>Gaëtan Faugère</b></sub></a><br /><a href="#tool-gfaugere" title="Tools">🔧</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/bhbuehler"><img src="https://avatars.githubusercontent.com/u/25541343?v=4?s=100" width="100px;" alt="bhbuehler"/><br /><sub><b>bhbuehler</b></sub></a><br /><a href="#content-bhbuehler" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/nyurik"><img src="https://avatars.githubusercontent.com/u/1641515?v=4?s=100" width="100px;" alt="Yuri Astrakhan"/><br /><sub><b>Yuri Astrakhan</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nyurik" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://azzamsa.com"><img src="https://avatars.githubusercontent.com/u/17734314?v=4?s=100" width="100px;" alt="azzamsa"/><br /><sub><b>azzamsa</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=azzamsa" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/mvanschellebeeck"><img src="https://avatars.githubusercontent.com/u/17671052?v=4?s=100" width="100px;" alt="mvanschellebeeck"/><br /><sub><b>mvanschellebeeck</b></sub></a><br /><a href="#content-mvanschellebeeck" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/aaarkid"><img src="https://avatars.githubusercontent.com/u/39987510?v=4?s=100" width="100px;" alt="Arkid"/><br /><sub><b>Arkid</b></sub></a><br /><a href="#content-aaarkid" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://tfpk.dev"><img src="https://avatars.githubusercontent.com/u/10906982?v=4?s=100" width="100px;" alt="Tom Kunc"/><br /><sub><b>Tom Kunc</b></sub></a><br /><a href="#content-tfpk" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/mfurak"><img src="https://avatars.githubusercontent.com/u/38523093?v=4?s=100" width="100px;" alt="Marek Furák"/><br /><sub><b>Marek Furák</b></sub></a><br /><a href="#content-mfurak" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://winter.cafe"><img src="https://avatars.githubusercontent.com/u/78392041?v=4?s=100" width="100px;" alt="Winter"/><br /><sub><b>Winter</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=winterqt" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://moritzboeh.me"><img src="https://avatars.githubusercontent.com/u/42215704?v=4?s=100" width="100px;" alt="Moritz Böhme"/><br /><sub><b>Moritz Böhme</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MoritzBoehme" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/craymel"><img src="https://avatars.githubusercontent.com/u/71062756?v=4?s=100" width="100px;" alt="craymel"/><br /><sub><b>craymel</b></sub></a><br /><a href="#content-craymel" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/tkburis"><img src="https://avatars.githubusercontent.com/u/20501289?v=4?s=100" width="100px;" alt="TK Buristrakul"/><br /><sub><b>TK Buristrakul</b></sub></a><br /><a href="#content-tkburis" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/HerschelW"><img src="https://avatars.githubusercontent.com/u/17935816?v=4?s=100" width="100px;" alt="Kent Worthington"/><br /><sub><b>Kent Worthington</b></sub></a><br /><a href="#content-HerschelW" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/seporterfield"><img src="https://avatars.githubusercontent.com/u/107010978?v=4?s=100" width="100px;" alt="seporterfield"/><br /><sub><b>seporterfield</b></sub></a><br /><a href="#content-seporterfield" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.linkedin.com/in/dbarrosop"><img src="https://avatars.githubusercontent.com/u/6246622?v=4?s=100" width="100px;" alt="David Barroso"/><br /><sub><b>David Barroso</b></sub></a><br /><a href="#infra-dbarrosop" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://distanz.ch"><img src="https://avatars.githubusercontent.com/u/539708?v=4?s=100" width="100px;" alt="Tobias Klauser"/><br /><sub><b>Tobias Klauser</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=tklauser" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/0xMySt1c"><img src="https://avatars.githubusercontent.com/u/101825630?v=4?s=100" width="100px;" alt="0xMySt1c"/><br /><sub><b>0xMySt1c</b></sub></a><br /><a href="#tool-0xMySt1c" title="Tools">🔧</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/AxolotlTears"><img src="https://avatars.githubusercontent.com/u/87157047?v=4?s=100" width="100px;" alt="Ten"/><br /><sub><b>Ten</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=AxolotlTears" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://h4x5p4c3.xyz"><img src="https://avatars.githubusercontent.com/u/66133688?v=4?s=100" width="100px;" alt="jones martin"/><br /><sub><b>jones martin</b></sub></a><br /><a href="#content-h4x5p4c3" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/cloppingemu"><img src="https://avatars.githubusercontent.com/u/12227963?v=4?s=100" width="100px;" alt="cloppingemu"/><br /><sub><b>cloppingemu</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cloppingemu" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://github.com/zeromicro/go-zero"><img src="https://avatars.githubusercontent.com/u/1918356?v=4?s=100" width="100px;" alt="Kevin Wan"/><br /><sub><b>Kevin Wan</b></sub></a><br /><a href="#content-kevwan" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://kurowasaruby.cn"><img src="https://avatars.githubusercontent.com/u/43495006?v=4?s=100" width="100px;" alt="Ruby"/><br /><sub><b>Ruby</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=wjwrh" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/alexandergill"><img src="https://avatars.githubusercontent.com/u/7033716?v=4?s=100" width="100px;" alt="Alexander Gill"/><br /><sub><b>Alexander Gill</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=alexandergill" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.linkedin.com/in/jarrod-sanders/"><img src="https://avatars.githubusercontent.com/u/50600614?v=4?s=100" width="100px;" alt="Jarrod Sanders"/><br /><sub><b>Jarrod Sanders</b></sub></a><br /><a href="#content-kawaiiPlat" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/platformer"><img src="https://avatars.githubusercontent.com/u/40146328?v=4?s=100" width="100px;" alt="Andrew Sen"/><br /><sub><b>Andrew Sen</b></sub></a><br /><a href="#content-platformer" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://grzegorz-zur.com/"><img src="https://avatars.githubusercontent.com/u/5297583?v=4?s=100" width="100px;" alt="Grzegorz Żur"/><br /><sub><b>Grzegorz Żur</b></sub></a><br /><a href="#content-grzegorz-zur" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/black-puppydog"><img src="https://avatars.githubusercontent.com/u/189241?v=4?s=100" width="100px;" alt="Daan Wynen"/><br /><sub><b>Daan Wynen</b></sub></a><br /><a href="#content-black-puppydog" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Anush008"><img src="https://avatars.githubusercontent.com/u/46051506?v=4?s=100" width="100px;" alt="Anush"/><br /><sub><b>Anush</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Anush008" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/shgew"><img src="https://avatars.githubusercontent.com/u/5584672?v=4?s=100" width="100px;" alt="Gleb Shevchenko"/><br /><sub><b>Gleb Shevchenko</b></sub></a><br /><a href="#content-shgew" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/mdmundo"><img src="https://avatars.githubusercontent.com/u/60408300?v=4?s=100" width="100px;" alt="Edmundo Paulino"/><br /><sub><b>Edmundo Paulino</b></sub></a><br /><a href="#infra-mdmundo" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/eroullit"><img src="https://avatars.githubusercontent.com/u/301795?v=4?s=100" width="100px;" alt="Emmanuel Roullit"/><br /><sub><b>Emmanuel Roullit</b></sub></a><br /><a href="#infra-eroullit" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://nidhalmessaoudi.herokuapp.com"><img src="https://avatars.githubusercontent.com/u/63377412?v=4?s=100" width="100px;" alt="Nidhal Messaoudi"/><br /><sub><b>Nidhal Messaoudi</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nidhalmessaoudi" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/MahdiBM"><img src="https://avatars.githubusercontent.com/u/54685446?v=4?s=100" width="100px;" alt="Mahdi Bahrami"/><br /><sub><b>Mahdi Bahrami</b></sub></a><br /><a href="#tool-MahdiBM" title="Tools">🔧</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Nagidal"><img src="https://avatars.githubusercontent.com/u/7075397?v=4?s=100" width="100px;" alt="Nagidal"/><br /><sub><b>Nagidal</b></sub></a><br /><a href="#content-Nagidal" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://adabrew.com"><img src="https://avatars.githubusercontent.com/u/25161597?v=4?s=100" width="100px;" alt="Adam Brewer"/><br /><sub><b>Adam Brewer</b></sub></a><br /><a href="#content-adamhb123" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/eugkhp"><img src="https://avatars.githubusercontent.com/u/25910599?v=4?s=100" width="100px;" alt="Eugene"/><br /><sub><b>Eugene</b></sub></a><br /><a href="#tool-eugkhp" title="Tools">🔧</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://social.linux.pizza/@navicore"><img src="https://avatars.githubusercontent.com/u/110999?v=4?s=100" width="100px;" alt="Ed Sweeney"/><br /><sub><b>Ed Sweeney</b></sub></a><br /><a href="#content-navicore" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/javihernant"><img src="https://avatars.githubusercontent.com/u/73640929?v=4?s=100" width="100px;" alt="javihernant"/><br /><sub><b>javihernant</b></sub></a><br /><a href="#content-javihernant" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/VegardMatthey"><img src="https://avatars.githubusercontent.com/u/59250656?v=4?s=100" width="100px;" alt="Vegard"/><br /><sub><b>Vegard</b></sub></a><br /><a href="#content-VegardMatthey" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/ryanwhitehouse"><img src="https://avatars.githubusercontent.com/u/13400784?v=4?s=100" width="100px;" alt="Ryan Whitehouse"/><br /><sub><b>Ryan Whitehouse</b></sub></a><br /><a href="#content-ryanwhitehouse" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/guoard"><img src="https://avatars.githubusercontent.com/u/65511355?v=4?s=100" width="100px;" alt="Ali Afsharzadeh"/><br /><sub><b>Ali Afsharzadeh</b></sub></a><br /><a href="#content-guoard" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="http://keogami.ml"><img src="https://avatars.githubusercontent.com/u/41939011?v=4?s=100" width="100px;" alt="Keogami"/><br /><sub><b>Keogami</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=keogami" title="Documentation">📖</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/ahresse"><img src="https://avatars.githubusercontent.com/u/28402488?v=4?s=100" width="100px;" alt="Alexandre Esse"/><br /><sub><b>Alexandre Esse</b></sub></a><br /><a href="#content-ahresse" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://resilient.tech"><img src="https://avatars.githubusercontent.com/u/16315650?v=4?s=100" width="100px;" alt="Sagar Vora"/><br /><sub><b>Sagar Vora</b></sub></a><br /><a href="#content-sagarvora" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/poneciak57"><img src="https://avatars.githubusercontent.com/u/94321164?v=4?s=100" width="100px;" alt="Kacper Poneta"/><br /><sub><b>Kacper Poneta</b></sub></a><br /><a href="#content-poneciak57" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://ktheory.com/"><img src="https://avatars.githubusercontent.com/u/975?v=4?s=100" width="100px;" alt="Aaron Suggs"/><br /><sub><b>Aaron Suggs</b></sub></a><br /><a href="#content-ktheory" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/alexwh"><img src="https://avatars.githubusercontent.com/u/1723612?v=4?s=100" width="100px;" alt="Alex"/><br /><sub><b>Alex</b></sub></a><br /><a href="#content-alexwh" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/stornquist"><img src="https://avatars.githubusercontent.com/u/42915664?v=4?s=100" width="100px;" alt="Sebastian Törnquist"/><br /><sub><b>Sebastian Törnquist</b></sub></a><br /><a href="#content-stornquist" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://smlavine.com"><img src="https://avatars.githubusercontent.com/u/33563640?v=4?s=100" width="100px;" alt="Sebastian LaVine"/><br /><sub><b>Sebastian LaVine</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=smlavine" title="Code">💻</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="http://www.alangerber.us"><img src="https://avatars.githubusercontent.com/u/201313?v=4?s=100" width="100px;" alt="Alan Gerber"/><br /><sub><b>Alan Gerber</b></sub></a><br /><a href="#content-akgerber" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://esotuvaka.github.io"><img src="https://avatars.githubusercontent.com/u/104941850?v=4?s=100" width="100px;" alt="Eric"/><br /><sub><b>Eric</b></sub></a><br /><a href="#content-esotuvaka" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/az0977776"><img src="https://avatars.githubusercontent.com/u/9172038?v=4?s=100" width="100px;" alt="Aaron Wang"/><br /><sub><b>Aaron Wang</b></sub></a><br /><a href="#content-az0977776" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/nmay231"><img src="https://avatars.githubusercontent.com/u/35386821?v=4?s=100" width="100px;" alt="Noah"/><br /><sub><b>Noah</b></sub></a><br /><a href="#content-nmay231" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/rb5014"><img src="https://avatars.githubusercontent.com/u/105397317?v=4?s=100" width="100px;" alt="rb5014"/><br /><sub><b>rb5014</b></sub></a><br /><a href="#content-rb5014" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/deedy5"><img src="https://avatars.githubusercontent.com/u/65482418?v=4?s=100" width="100px;" alt="deedy5"/><br /><sub><b>deedy5</b></sub></a><br /><a href="#content-deedy5" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/lionel-rowe"><img src="https://avatars.githubusercontent.com/u/26078826?v=4?s=100" width="100px;" alt="lionel-rowe"/><br /><sub><b>lionel-rowe</b></sub></a><br /><a href="#content-lionel-rowe" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Ben2917"><img src="https://avatars.githubusercontent.com/u/10279994?v=4?s=100" width="100px;" alt="Ben"/><br /><sub><b>Ben</b></sub></a><br /><a href="#content-Ben2917" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/b1ue64"><img src="https://avatars.githubusercontent.com/u/77976308?v=4?s=100" width="100px;" alt="b1ue64"/><br /><sub><b>b1ue64</b></sub></a><br /><a href="#content-b1ue64" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/lazywalker"><img src="https://avatars.githubusercontent.com/u/53956?v=4?s=100" width="100px;" alt="lazywalker"/><br /><sub><b>lazywalker</b></sub></a><br /><a href="#content-lazywalker" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/proofconstruction"><img src="https://avatars.githubusercontent.com/u/74747193?v=4?s=100" width="100px;" alt="proofconstruction"/><br /><sub><b>proofconstruction</b></sub></a><br /><a href="#infra-proofconstruction" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.youtube.com/channel/UCQCjA6qUutAtWqkCA4Z36CQ"><img src="https://avatars.githubusercontent.com/u/16007179?v=4?s=100" width="100px;" alt="IVIURRAY"/><br /><sub><b>IVIURRAY</b></sub></a><br /><a href="#content-IVIURRAY" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/b-apperlo"><img src="https://avatars.githubusercontent.com/u/91734527?v=4?s=100" width="100px;" alt="Bert Apperlo"/><br /><sub><b>Bert Apperlo</b></sub></a><br /><a href="#content-b-apperlo" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://fwdekker.com/"><img src="https://avatars.githubusercontent.com/u/13442533?v=4?s=100" width="100px;" alt="Florine W. Dekker"/><br /><sub><b>Florine W. Dekker</b></sub></a><br /><a href="#content-FWDekker" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/luhem7"><img src="https://avatars.githubusercontent.com/u/4008215?v=4?s=100" width="100px;" alt="Mehul Gangavelli"/><br /><sub><b>Mehul Gangavelli</b></sub></a><br /><a href="#content-luhem7" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Frosthage"><img src="https://avatars.githubusercontent.com/u/14823314?v=4?s=100" width="100px;" alt="Mikael Frosthage"/><br /><sub><b>Mikael Frosthage</b></sub></a><br /><a href="#content-Frosthage" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://robertfry.xyz"><img src="https://avatars.githubusercontent.com/u/43712054?v=4?s=100" width="100px;" alt="Robert Fry"/><br /><sub><b>Robert Fry</b></sub></a><br /><a href="#content-robertefry" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/tajo48"><img src="https://avatars.githubusercontent.com/u/55502906?v=4?s=100" width="100px;" alt="tajo48"/><br /><sub><b>tajo48</b></sub></a><br /><a href="#content-tajo48" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://anishchhetri.com.np"><img src="https://avatars.githubusercontent.com/u/98446102?v=4?s=100" width="100px;" alt="Anish"/><br /><sub><b>Anish</b></sub></a><br /><a href="#content-novanish" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/vnprc"><img src="https://avatars.githubusercontent.com/u/9425366?v=4?s=100" width="100px;" alt="vnprc"/><br /><sub><b>vnprc</b></sub></a><br /><a href="#content-vnprc" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://androecia.net"><img src="https://avatars.githubusercontent.com/u/61999256?v=4?s=100" width="100px;" alt="Joshua Carlson"/><br /><sub><b>Joshua Carlson</b></sub></a><br /><a href="#content-jrcarl624" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://johndesilencio.me"><img src="https://avatars.githubusercontent.com/u/20136554?v=4?s=100" width="100px;" alt="Nicholas R. Smith"/><br /><sub><b>Nicholas R. Smith</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=johnDeSilencio" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://alexfertel.me"><img src="https://avatars.githubusercontent.com/u/22298999?v=4?s=100" width="100px;" alt="Alexander González"/><br /><sub><b>Alexander González</b></sub></a><br /><a href="#content-alexfertel" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/softarn"><img src="https://avatars.githubusercontent.com/u/517619?v=4?s=100" width="100px;" alt="Marcus Höjvall"/><br /><sub><b>Marcus Höjvall</b></sub></a><br /><a href="#content-softarn" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/barlevalon"><img src="https://avatars.githubusercontent.com/u/3397911?v=4?s=100" width="100px;" alt="Alon Hearter"/><br /><sub><b>Alon Hearter</b></sub></a><br /><a href="#content-barlevalon" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/shirts"><img src="https://avatars.githubusercontent.com/u/4952151?v=4?s=100" width="100px;" alt="shirts"/><br /><sub><b>shirts</b></sub></a><br /><a href="#content-shirts" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/eLVas"><img src="https://avatars.githubusercontent.com/u/6797156?v=4?s=100" width="100px;" alt="Ivan Vasiunyk"/><br /><sub><b>Ivan Vasiunyk</b></sub></a><br /><a href="#content-eLVas" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://mo8it.com"><img src="https://avatars.githubusercontent.com/u/76752051?v=4?s=100" width="100px;" alt="Mo"/><br /><sub><b>Mo</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=mo8it" title="Code">💻</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/x10an14"><img src="https://avatars.githubusercontent.com/u/710608?v=4?s=100" width="100px;" alt="x10an14"/><br /><sub><b>x10an14</b></sub></a><br /><a href="#infra-x10an14" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/gabay"><img src="https://avatars.githubusercontent.com/u/5773610?v=4?s=100" width="100px;" alt="Roi Gabay"/><br /><sub><b>Roi Gabay</b></sub></a><br /><a href="#content-gabay" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/mkovaxx"><img src="https://avatars.githubusercontent.com/u/481354?v=4?s=100" width="100px;" alt="Máté Kovács"/><br /><sub><b>Máté Kovács</b></sub></a><br /><a href="#content-mkovaxx" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://szabgab.com/"><img src="https://avatars.githubusercontent.com/u/48833?v=4?s=100" width="100px;" alt="Gábor Szabó"/><br /><sub><b>Gábor Szabó</b></sub></a><br /><a href="#content-szabgab" title="Content">🖋</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://moduslaborandi.net"><img src="https://avatars.githubusercontent.com/u/3340793?v=4?s=100" width="100px;" alt="Yamila Moreno"/><br /><sub><b>Yamila Moreno</b></sub></a><br /><a href="#content-yamila-moreno" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/willhack"><img src="https://avatars.githubusercontent.com/u/18036720?v=4?s=100" width="100px;" alt="Will Hack"/><br /><sub><b>Will Hack</b></sub></a><br /><a href="#content-willhack" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://cancompute.tech"><img src="https://avatars.githubusercontent.com/u/2052646?v=4?s=100" width="100px;" alt="Michael"/><br /><sub><b>Michael</b></sub></a><br /><a href="#content-bean5" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://www.sadiqpk.org"><img src="https://avatars.githubusercontent.com/u/1289514?v=4?s=100" width="100px;" alt="Mohammed Sadiq"/><br /><sub><b>Mohammed Sadiq</b></sub></a><br /><a href="#content-pksadiq" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/Jak-Ch-ll"><img src="https://avatars.githubusercontent.com/u/56225668?v=4?s=100" width="100px;" alt="Jakob"/><br /><sub><b>Jakob</b></sub></a><br /><a href="#content-Jak-Ch-ll" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="http://oscarbonilla.com"><img src="https://avatars.githubusercontent.com/u/4950?v=4?s=100" width="100px;" alt="Oscar Bonilla"/><br /><sub><b>Oscar Bonilla</b></sub></a><br /><a href="#content-ob" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/husjon"><img src="https://avatars.githubusercontent.com/u/554229?v=4?s=100" width="100px;" alt="Jon Erling Hustadnes"/><br /><sub><b>Jon Erling Hustadnes</b></sub></a><br /><a href="#content-husjon" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/CobaltCause"><img src="https://avatars.githubusercontent.com/u/7003738?v=4?s=100" width="100px;" alt="Charles Hall"/><br /><sub><b>Charles Hall</b></sub></a><br /><a href="#infra-CobaltCause" title="Infrastructure (Hosting, Build-Tools, etc)">🚇</a></td>
+    </tr>
+    <tr>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/krmpotic"><img src="https://avatars.githubusercontent.com/u/10350645?v=4?s=100" width="100px;" alt="Luka Krmpotić"/><br /><sub><b>Luka Krmpotić</b></sub></a><br /><a href="#content-krmpotic" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/jurglic"><img src="https://avatars.githubusercontent.com/u/112600?v=4?s=100" width="100px;" alt="Jurglic"/><br /><sub><b>Jurglic</b></sub></a><br /><a href="#content-jurglic" title="Content">🖋</a></td>
+      <td align="center" valign="top" width="12.5%"><a href="https://github.com/OfirLauber"><img src="https://avatars.githubusercontent.com/u/5631030?v=4?s=100" width="100px;" alt="Ofir Lauber"/><br /><sub><b>Ofir Lauber</b></sub></a><br /><a href="#content-OfirLauber" title="Content">🖋</a></td>
+    </tr>
+  </tbody>
+</table>
+
+<!-- markdownlint-restore -->
+<!-- prettier-ignore-end -->
+
+<!-- ALL-CONTRIBUTORS-LIST:END -->
+
+This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!

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.toml

@@ -1,23 +1,30 @@
 [package]
 name = "rustlings"
-version = "4.3.0"
-authors = ["Marisa <mokou@posteo.de>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
-edition = "2018"
+description = "Small exercises to get you used to reading and writing Rust code!"
+version = "5.6.1"
+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"]}
+indicatif = "0.17.6"
+console = "0.15"
+notify = "4.0"
+toml = "0.7.6"
+regex = "1.5"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0.81"
+home = "0.5.3"
+glob = "0.3.0"
+clap = { version = "4.4.0", features = ["derive"] }
 
 [[bin]]
 name = "rustlings"
 path = "src/main.rs"
 
 [dev-dependencies]
-assert_cmd = "0.11.0"
-predicates = "1.0.1"
+assert_cmd = "2.0.12"
+predicates = "3.0.3"
 glob = "0.3.0"

README.md

@@ -1,9 +1,9 @@
-<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
-[![All Contributors](https://img.shields.io/badge/all_contributors-89-orange.svg?style=flat-square)](#contributors-)
-<!-- ALL-CONTRIBUTORS-BADGE:END -->
+<div class="oranda-hide">
 
 # rustlings 🦀❤️
 
+</div>
+
 Greetings and welcome to `rustlings`. This project contains small exercises to get you used to reading and writing Rust code. This includes reading and responding to compiler messages!
 
 _...looking for the old, web-based version of Rustlings? Try [here](https://github.com/rust-lang/rustlings/tree/rustlings-1)_
@@ -16,57 +16,77 @@ Alternatively, for a first-time Rust learner, there are several other resources:
 ## Getting Started
 
 _Note: If you're on MacOS, make sure you've installed Xcode and its developer tools by typing `xcode-select --install`._
+_Note: If you're on Linux, make sure you've installed gcc. Deb: `sudo apt install gcc`. Yum: `sudo yum -y install gcc`._
 
-You will need to have Rust installed. You can get it by visiting https://rustup.rs. This'll also install Cargo, Rust's package/project manager.
+You will need to have Rust installed. You can get it by visiting <https://rustup.rs>. This'll also install Cargo, Rust's package/project manager.
 
 ## MacOS/Linux
 
 Just run:
 
 ```bash
-curl -L https://git.io/install-rustlings | 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
+```
+
+Or if you want it to be installed to a different path:
+
+```bash
+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!
 
+### Nix
+
+Basically: Clone the repository at the latest tag, finally run `nix develop` or `nix-shell`.
+
+```bash
+# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 5.6.1)
+git clone -b 5.6.1 --depth 1 https://github.com/rust-lang/rustlings
+cd rustlings
+# if nix version > 2.3
+nix develop
+# if nix version <= 2.3
+nix-shell
+```
+
 ## Windows
 
-In PowerShell, set `ExecutionPolicy` to `RemoteSigned`:
+In PowerShell (Run as Administrator), set `ExecutionPolicy` to `RemoteSigned`:
 
-```ps
-Set-ExecutionPolicy RemoteSigned
+```ps1
+Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
 ```
 
 Then, you can run:
 
-```ps
-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
+```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.
+To install Rustlings. Same as on MacOS/Linux, you will have access to the `rustlings` command after it. Keep in mind that this works best in PowerShell, and any other terminals may give you errors.
 
-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/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/rust-lang/rustlings)
 
-[Open in Gitpod](https://gitpod.io/#https://github.com/rust-lang/rustlings)
+[![Open Rustlings On Codespaces](https://github.com/codespaces/badge.svg)](https://github.com/codespaces/new/?repo=rust-lang%2Frustlings&ref=main)
 
 ## Manually
 
-Basically: Clone the repository, checkout to the latest tag, run `cargo install`.
+Basically: Clone the repository at the latest tag, run `cargo install --path .`.
 
 ```bash
-git clone https://github.com/rust-lang/rustlings
+# find out the latest version at https://github.com/rust-lang/rustlings/releases/latest (on edit 5.6.1)
+git clone -b 5.6.1 --depth 1 https://github.com/rust-lang/rustlings
 cd rustlings
-git checkout tags/4.3.0 # or whatever the latest version is (find out at https://github.com/rust-lang/rustlings/releases/latest)
 cargo install --force --path .
 ```
 
 If there are installation errors, ensure that your toolchain is up to date. For the latest, run:
+
 ```bash
 rustup update
 ```
@@ -97,14 +117,27 @@ In case you want to go by your own order, or want to only verify a single exerci
 rustlings run myExercise1
 ```
 
+Or simply use the following command to run the next unsolved exercise in the course:
+
+```bash
+rustlings run next
+```
+
 In case you get stuck, you can run the following command to get a hint for your
 exercise:
 
-``` bash
+```bash
 rustlings hint myExercise1
 ```
 
+You can also get the hint for the next unsolved exercise with the following command:
+
+```bash
+rustlings hint next
+```
+
 To check your progress, you can run the following command:
+
 ```bash
 rustlings list
 ```
@@ -113,176 +146,35 @@ rustlings list
 
 After every couple of sections, there will be a quiz that'll test your knowledge on a bunch of sections at once. These quizzes are found in `exercises/quizN.rs`.
 
+## Enabling `rust-analyzer`
+
+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
 
 Once you've completed Rustlings, put your new knowledge to good use! Continue practicing your Rust skills by building your own projects, contributing to Rustlings, or finding other open-source projects to contribute to.
 
 ## Uninstalling Rustlings
 
-If you want to remove Rustlings from your system, there's two steps. First, you'll need to remove the exercises folder that the install script created
+If you want to remove Rustlings from your system, there are two steps. First, you'll need to remove the exercises folder that the install script created
 for you:
 
-``` bash
+```bash
 rm -rf rustlings # or your custom folder name, if you chose and or renamed it
 ```
 
-Second, since Rustlings got installed via `cargo install`, it's only reasonable to assume that you can also remove it using Cargo, and
-exactly that is the case. Run `cargo uninstall` to remove the `rustlings` binary:
+Second, run `cargo uninstall` to remove the `rustlings` binary:
 
-``` bash
+```bash
 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).
+See [CONTRIBUTING.md](https://github.com/rust-lang/rustlings/blob/main/CONTRIBUTING.md).
 
 ## Contributors ✨
 
-Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):
-
-<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
-<!-- prettier-ignore-start -->
-<!-- markdownlint-disable -->
-<table>
-  <tr>
-    <td align="center"><a href="http://carol-nichols.com"><img src="https://avatars2.githubusercontent.com/u/193874?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Carol (Nichols &#124;&#124; Goulding)</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=carols10cents" title="Code">💻</a> <a href="#content-carols10cents" title="Content">🖋</a></td>
-    <td align="center"><a href="https://twitter.com/QuietMisdreavus"><img src="https://avatars2.githubusercontent.com/u/5217170?v=4?s=100" width="100px;" alt=""/><br /><sub><b>QuietMisdreavus</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=QuietMisdreavus" title="Code">💻</a> <a href="#content-QuietMisdreavus" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/robertlugg"><img src="https://avatars0.githubusercontent.com/u/6054540?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Robert M Lugg</b></sub></a><br /><a href="#content-robertlugg" title="Content">🖋</a></td>
-    <td align="center"><a href="https://hynek.me/about/"><img src="https://avatars3.githubusercontent.com/u/41240?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Hynek Schlawack</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=hynek" title="Code">💻</a></td>
-    <td align="center"><a href="https://spacekookie.de"><img src="https://avatars0.githubusercontent.com/u/7669898?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Katharina Fey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=spacekookie" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/lukabavdaz"><img src="https://avatars0.githubusercontent.com/u/9624558?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lukabavdaz</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lukabavdaz" title="Code">💻</a> <a href="#content-lukabavdaz" title="Content">🖋</a></td>
-    <td align="center"><a href="http://vestera.as"><img src="https://avatars2.githubusercontent.com/u/4187449?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Erik Vesteraas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=evestera" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/Delet0r"><img src="https://avatars1.githubusercontent.com/u/23195618?v=4?s=100" width="100px;" alt=""/><br /><sub><b>delet0r</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Delet0r" title="Code">💻</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="http://phinary.ca"><img src="https://avatars1.githubusercontent.com/u/10522375?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Shaun Bennett</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=shaunbennett" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/abagshaw"><img src="https://avatars2.githubusercontent.com/u/8594541?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Andrew Bagshaw</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=abagshaw" title="Code">💻</a></td>
-    <td align="center"><a href="https://ai6ua.net/"><img src="https://avatars2.githubusercontent.com/u/175578?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kyle Isom</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=kisom" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/ColinPitrat"><img src="https://avatars3.githubusercontent.com/u/1541863?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Colin Pitrat</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ColinPitrat" title="Code">💻</a></td>
-    <td align="center"><a href="https://zacanger.com"><img src="https://avatars3.githubusercontent.com/u/12520493?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zac Anger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=zacanger" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/mgeier"><img src="https://avatars1.githubusercontent.com/u/705404?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Matthias Geier</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=mgeier" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/cjpearce"><img src="https://avatars1.githubusercontent.com/u/3453268?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Chris Pearce</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cjpearce" title="Code">💻</a></td>
-    <td align="center"><a href="https://yvan-sraka.github.io"><img src="https://avatars2.githubusercontent.com/u/705213?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yvan Sraka</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=yvan-sraka" title="Code">💻</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/dendi239"><img src="https://avatars3.githubusercontent.com/u/16478650?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Denys Smirnov</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=dendi239" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/eddyp"><img src="https://avatars2.githubusercontent.com/u/123772?v=4?s=100" width="100px;" alt=""/><br /><sub><b>eddyp</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=eddyp" title="Code">💻</a></td>
-    <td align="center"><a href="http://about.me/BrianKung"><img src="https://avatars1.githubusercontent.com/u/2836167?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Brian Kung</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=briankung" title="Code">💻</a> <a href="#content-briankung" title="Content">🖋</a></td>
-    <td align="center"><a href="https://rcousineau.gitlab.io"><img src="https://avatars3.githubusercontent.com/u/281039?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Russell</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=miller-time" title="Code">💻</a></td>
-    <td align="center"><a href="http://danwilhelm.com"><img src="https://avatars3.githubusercontent.com/u/6137185?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dan Wilhelm</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=danwilhelm" title="Documentation">📖</a></td>
-    <td align="center"><a href="https://github.com/Jesse-Cameron"><img src="https://avatars3.githubusercontent.com/u/3723654?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jesse</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Jesse-Cameron" title="Code">💻</a> <a href="#content-Jesse-Cameron" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/MrFroop"><img src="https://avatars3.githubusercontent.com/u/196700?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fredrik Jambrén</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=MrFroop" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/petemcfarlane"><img src="https://avatars3.githubusercontent.com/u/3472717?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pete McFarlane</b></sub></a><br /><a href="#content-petemcfarlane" title="Content">🖋</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/nkanderson"><img src="https://avatars0.githubusercontent.com/u/4128825?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nkanderson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nkanderson" title="Code">💻</a> <a href="#content-nkanderson" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/ajaxm"><img src="https://avatars0.githubusercontent.com/u/13360138?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ajax M</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ajaxm" title="Documentation">📖</a></td>
-    <td align="center"><a href="https://dylnuge.com"><img src="https://avatars2.githubusercontent.com/u/118624?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dylan Nugent</b></sub></a><br /><a href="#content-Dylnuge" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/vyaslav"><img src="https://avatars0.githubusercontent.com/u/1385427?v=4?s=100" width="100px;" alt=""/><br /><sub><b>vyaslav</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=vyaslav" title="Code">💻</a> <a href="#content-vyaslav" title="Content">🖋</a></td>
-    <td align="center"><a href="https://join.sfxd.org"><img src="https://avatars1.githubusercontent.com/u/17297466?v=4?s=100" width="100px;" alt=""/><br /><sub><b>George</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=gdoenlen" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/nyxtom"><img src="https://avatars2.githubusercontent.com/u/222763?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Thomas Holloway</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=nyxtom" title="Code">💻</a> <a href="#content-nyxtom" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/workingjubilee"><img src="https://avatars1.githubusercontent.com/u/46493976?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jubilee</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=workingjubilee" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/WofWca"><img src="https://avatars1.githubusercontent.com/u/39462442?v=4?s=100" width="100px;" alt=""/><br /><sub><b>WofWca</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=WofWca" title="Code">💻</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/jrvidal"><img src="https://avatars0.githubusercontent.com/u/1636604?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Roberto Vidal</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=jrvidal" title="Documentation">📖</a> <a href="#ideas-jrvidal" title="Ideas, Planning, & Feedback">🤔</a> <a href="#maintenance-jrvidal" title="Maintenance">🚧</a></td>
-    <td align="center"><a href="https://github.com/jensim"><img src="https://avatars0.githubusercontent.com/u/3663856?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jens</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=jensim" title="Documentation">📖</a></td>
-    <td align="center"><a href="http://rahatah.me/d"><img src="https://avatars3.githubusercontent.com/u/3174006?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rahat Ahmed</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=rahatarmanahmed" title="Documentation">📖</a></td>
-    <td align="center"><a href="https://github.com/AbdouSeck"><img src="https://avatars2.githubusercontent.com/u/6490055?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Abdou Seck</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=AbdouSeck" title="Code">💻</a> <a href="#content-AbdouSeck" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAbdouSeck" title="Reviewed Pull Requests">👀</a></td>
-    <td align="center"><a href="https://codehearts.com"><img src="https://avatars0.githubusercontent.com/u/2885412?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Katie</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=codehearts" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/Socratides"><img src="https://avatars3.githubusercontent.com/u/27732983?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Socrates</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Socratides" title="Documentation">📖</a></td>
-    <td align="center"><a href="https://github.com/gnodarse"><img src="https://avatars3.githubusercontent.com/u/46761795?v=4?s=100" width="100px;" alt=""/><br /><sub><b>gnodarse</b></sub></a><br /><a href="#content-gnodarse" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/harrisonmetz"><img src="https://avatars1.githubusercontent.com/u/7883408?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Harrison Metzger</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=harrisonmetz" title="Code">💻</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/TorbenJ"><img src="https://avatars2.githubusercontent.com/u/9077102?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Torben Jonas</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=TorbenJ" title="Code">💻</a> <a href="#content-TorbenJ" title="Content">🖋</a></td>
-    <td align="center"><a href="http://paulbissex.com/"><img src="https://avatars0.githubusercontent.com/u/641?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Paul Bissex</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=pbx" title="Documentation">📖</a></td>
-    <td align="center"><a href="https://github.com/sjmann"><img src="https://avatars0.githubusercontent.com/u/6589896?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Steven Mann</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sjmann" title="Code">💻</a> <a href="#content-sjmann" title="Content">🖋</a></td>
-    <td align="center"><a href="https://smmdb.net/"><img src="https://avatars2.githubusercontent.com/u/5855071?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mario Reder</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Tarnadas" title="Code">💻</a> <a href="#content-Tarnadas" title="Content">🖋</a></td>
-    <td align="center"><a href="https://keybase.io/skim"><img src="https://avatars0.githubusercontent.com/u/47347?v=4?s=100" width="100px;" alt=""/><br /><sub><b>skim</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sl4m" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/sanjaykdragon"><img src="https://avatars1.githubusercontent.com/u/10261698?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sanjay K</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=sanjaykdragon" title="Code">💻</a> <a href="#content-sanjaykdragon" title="Content">🖋</a></td>
-    <td align="center"><a href="http://www.rohanjain.in"><img src="https://avatars1.githubusercontent.com/u/343499?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rohan Jain</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=crodjer" title="Code">💻</a></td>
-    <td align="center"><a href="https://www.saidaspen.se"><img src="https://avatars1.githubusercontent.com/u/7727687?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Said Aspen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=saidaspen" title="Code">💻</a> <a href="#content-saidaspen" title="Content">🖋</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/uce"><img src="https://avatars3.githubusercontent.com/u/1756620?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ufuk Celebi</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=uce" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/lebedevsergey"><img src="https://avatars2.githubusercontent.com/u/7325764?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lebedevsergey</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=lebedevsergey" title="Documentation">📖</a></td>
-    <td align="center"><a href="https://github.com/avrong"><img src="https://avatars2.githubusercontent.com/u/6342851?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Aleksei Trifonov</b></sub></a><br /><a href="#content-avrong" title="Content">🖋</a></td>
-    <td align="center"><a href="https://drn.ie"><img src="https://avatars2.githubusercontent.com/u/411136?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Darren Meehan</b></sub></a><br /><a href="#content-Darrenmeehan" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/jihchi"><img src="https://avatars1.githubusercontent.com/u/87983?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jihchi Lee</b></sub></a><br /><a href="#content-jihchi" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/bertonha"><img src="https://avatars3.githubusercontent.com/u/1225902?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christofer Bertonha</b></sub></a><br /><a href="#content-bertonha" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/apatniv"><img src="https://avatars2.githubusercontent.com/u/22565917?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Vivek Bharath Akupatni</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Code">💻</a> <a href="https://github.com/rust-lang/rustlings/commits?author=apatniv" title="Tests">⚠️</a></td>
-    <td align="center"><a href="https://github.com/DiD92"><img src="https://avatars3.githubusercontent.com/u/6002416?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dídac Sementé Fernández</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=DiD92" title="Code">💻</a> <a href="#content-DiD92" title="Content">🖋</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/wrobstory"><img src="https://avatars3.githubusercontent.com/u/2601457?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rob Story</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=wrobstory" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/siobhanjacobson"><img src="https://avatars2.githubusercontent.com/u/28983835?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Siobhan Jacobson</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=siobhanjacobson" title="Code">💻</a></td>
-    <td align="center"><a href="https://www.linkedin.com/in/evancarroll/"><img src="https://avatars2.githubusercontent.com/u/19922?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Evan Carroll</b></sub></a><br /><a href="#content-EvanCarroll" title="Content">🖋</a></td>
-    <td align="center"><a href="http://www.jawaadmahmood.com"><img src="https://avatars3.githubusercontent.com/u/95606?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jawaad Mahmood</b></sub></a><br /><a href="#content-jmahmood" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/GaurangTandon"><img src="https://avatars1.githubusercontent.com/u/6308683?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Gaurang Tandon</b></sub></a><br /><a href="#content-GaurangTandon" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/dev-cyprium"><img src="https://avatars1.githubusercontent.com/u/6002628?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stefan Kupresak</b></sub></a><br /><a href="#content-dev-cyprium" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/greg-el"><img src="https://avatars3.githubusercontent.com/u/45019882?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Greg Leonard</b></sub></a><br /><a href="#content-greg-el" title="Content">🖋</a></td>
-    <td align="center"><a href="https://ryanpcmcquen.org"><img src="https://avatars3.githubusercontent.com/u/772937?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ryan McQuen</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=ryanpcmcquen" title="Code">💻</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/AnnikaCodes"><img src="https://avatars3.githubusercontent.com/u/56906084?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Annika</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/pulls?q=is%3Apr+reviewed-by%3AAnnikaCodes" title="Reviewed Pull Requests">👀</a></td>
-    <td align="center"><a href="https://darnuria.eu"><img src="https://avatars1.githubusercontent.com/u/2827553?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Axel Viala</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=darnuria" title="Code">💻</a></td>
-    <td align="center"><a href="https://sazid.github.io"><img src="https://avatars1.githubusercontent.com/u/2370167?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mohammed Sazid Al Rashid</b></sub></a><br /><a href="#content-sazid" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=sazid" title="Code">💻</a></td>
-    <td align="center"><a href="https://codingthemsoftly.com"><img src="https://avatars1.githubusercontent.com/u/17479099?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Caleb Webber</b></sub></a><br /><a href="#maintenance-seeplusplus" title="Maintenance">🚧</a></td>
-    <td align="center"><a href="https://github.com/pcn"><img src="https://avatars2.githubusercontent.com/u/1056756?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Peter N</b></sub></a><br /><a href="#maintenance-pcn" title="Maintenance">🚧</a></td>
-    <td align="center"><a href="https://github.com/seancad"><img src="https://avatars1.githubusercontent.com/u/47405611?v=4?s=100" width="100px;" alt=""/><br /><sub><b>seancad</b></sub></a><br /><a href="#maintenance-seancad" title="Maintenance">🚧</a></td>
-    <td align="center"><a href="http://willhayworth.com"><img src="https://avatars3.githubusercontent.com/u/181174?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Will Hayworth</b></sub></a><br /><a href="#content-wsh" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/chrizel"><img src="https://avatars3.githubusercontent.com/u/20802?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christian Zeller</b></sub></a><br /><a href="#content-chrizel" title="Content">🖋</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/jfchevrette"><img src="https://avatars.githubusercontent.com/u/3001?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jean-Francois Chevrette</b></sub></a><br /><a href="#content-jfchevrette" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=jfchevrette" title="Code">💻</a></td>
-    <td align="center"><a href="https://github.com/jbaber"><img src="https://avatars.githubusercontent.com/u/1908117?v=4?s=100" width="100px;" alt=""/><br /><sub><b>John Baber-Lucero</b></sub></a><br /><a href="#content-jbaber" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/tal-zvon"><img src="https://avatars.githubusercontent.com/u/3195851?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Tal</b></sub></a><br /><a href="#content-tal-zvon" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/apogeeoak"><img src="https://avatars.githubusercontent.com/u/59737221?v=4?s=100" width="100px;" alt=""/><br /><sub><b>apogeeoak</b></sub></a><br /><a href="#content-apogeeoak" title="Content">🖋</a> <a href="https://github.com/rust-lang/rustlings/commits?author=apogeeoak" title="Code">💻</a></td>
-    <td align="center"><a href="http://www.garfieldtech.com/"><img src="https://avatars.githubusercontent.com/u/254863?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Larry Garfield</b></sub></a><br /><a href="#content-Crell" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/circumspect"><img src="https://avatars.githubusercontent.com/u/40770208?v=4?s=100" width="100px;" alt=""/><br /><sub><b>circumspect</b></sub></a><br /><a href="#content-circumspect" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/cjwyett"><img src="https://avatars.githubusercontent.com/u/34195737?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Cyrus Wyett</b></sub></a><br /><a href="#content-cjwyett" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/cadolphs"><img src="https://avatars.githubusercontent.com/u/13894820?v=4?s=100" width="100px;" alt=""/><br /><sub><b>cadolphs</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=cadolphs" title="Code">💻</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://www.haveneer.com"><img src="https://avatars.githubusercontent.com/u/26146722?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pascal H.</b></sub></a><br /><a href="#content-hpwxf" title="Content">🖋</a></td>
-    <td align="center"><a href="https://twitter.com/chapeupreto"><img src="https://avatars.githubusercontent.com/u/834048?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rod Elias</b></sub></a><br /><a href="#content-chapeupreto" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/blerchy"><img src="https://avatars.githubusercontent.com/u/2555355?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Matt Lebl</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=blerchy" title="Code">💻</a></td>
-    <td align="center"><a href="http://flakolefluk.dev"><img src="https://avatars.githubusercontent.com/u/11986564?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ignacio Le Fluk</b></sub></a><br /><a href="#content-flakolefluk" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/tlyu"><img src="https://avatars.githubusercontent.com/u/431873?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Taylor Yu</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=tlyu" title="Code">💻</a> <a href="#content-tlyu" title="Content">🖋</a></td>
-    <td align="center"><a href="https://zerotask.github.io"><img src="https://avatars.githubusercontent.com/u/20150243?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Patrick Hintermayer</b></sub></a><br /><a href="https://github.com/rust-lang/rustlings/commits?author=Zerotask" title="Code">💻</a></td>
-    <td align="center"><a href="https://petkopavlovski.com/"><img src="https://avatars.githubusercontent.com/u/32264020?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pete Pavlovski</b></sub></a><br /><a href="#content-arthas168" title="Content">🖋</a></td>
-    <td align="center"><a href="https://github.com/k12ish"><img src="https://avatars.githubusercontent.com/u/45272873?v=4?s=100" width="100px;" alt=""/><br /><sub><b>k12ish</b></sub></a><br /><a href="#content-k12ish" title="Content">🖋</a></td>
-  </tr>
-  <tr>
-    <td align="center"><a href="https://github.com/hongshaoyang"><img src="https://avatars.githubusercontent.com/u/19281800?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Shao Yang Hong</b></sub></a><br /><a href="#content-hongshaoyang" title="Content">🖋</a></td>
-  </tr>
-</table>
-
-<!-- markdownlint-restore -->
-<!-- prettier-ignore-end -->
-
-<!-- ALL-CONTRIBUTORS-LIST:END -->
-
-This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!
+Thanks goes to the wonderful people listed in [AUTHORS.md](https://github.com/rust-lang/rustlings/blob/main/AUTHORS.md) 🎉

default_out.txt

@@ -1,25 +0,0 @@
-Thanks for installing Rustlings!
-
-Is this your first time? Don't worry, Rustlings was made for beginners! We are
-going to teach you a lot of things about Rust, but before we can get
-started, here's a couple of notes about how Rustlings operates:
-
-1. The central concept behind Rustlings is that you solve exercises. These
-   exercises usually have some sort of syntax error in them, which will cause
-   them to fail compilation or testing. Sometimes there's a logic error instead
-   of a syntax error. No matter what error, it's your job to find it and fix it!
-   You'll know when you fixed it because then, the exercise will compile and
-   Rustlings will be able to move on to the next exercise.
-2. If you run Rustlings in watch mode (which we recommend), it'll automatically
-   start with the first exercise. Don't get confused by an error message popping
-   up as soon as you run Rustlings! This is part of the exercise that you're
-   supposed to solve, so open the exercise file in an editor and start your
-   detective work!
-3. If you're stuck on an exercise, there is a helpful hint you can view by typing
-   'hint' (in watch mode), or running `rustlings hint myexercise`.
-4. If an exercise doesn't make sense to you, feel free to open an issue on GitHub!
-   (https://github.com/rust-lang/rustlings/issues/new). We look at every issue,
-   and sometimes, other learners do too so you can help each other out!
-
-Got all that? Great! To get started, run `rustlings watch` in order to get the first
-exercise. Make sure to have your editor open!

exercises/README.md

@@ -1,24 +1,27 @@
 # 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                | §7.2          |
-| collections            | §8.1          |
-| 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         | §4.1-2              |
+| 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               |
+| iterators              | §13.2-4             |
+| threads                | §16.1-3             |
+| smart_pointers         | §15, §16.3          |
+| macros                 | §19.6               |
+| clippy                 | §21.4               |
+| conversions            | n/a                 |

exercises/clippy/README.md

@@ -1,8 +1,10 @@
-### Clippy
+# Clippy
 
 The Clippy tool is a collection of lints to analyze your code so you can catch common mistakes and improve your Rust code.
 
 If you used the installation script for Rustlings, Clippy should be already installed.
 If not you can install it manually via `rustup component add clippy`.
 
-For more information about Clippy lints, please see [their documentation page](https://rust-lang.github.io/rust-clippy/master/).
+## Further information
+
+- [GitHub Repository](https://github.com/rust-lang/rust-clippy).

exercises/clippy/clippy1.rs

@@ -1,17 +1,26 @@
 // clippy1.rs
-// The Clippy tool is a collection of lints to analyze your code
-// so you can catch common mistakes and improve your Rust code.
 //
-// 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 :)
+// The Clippy tool is a collection of lints to analyze your code so you can
+// catch common mistakes and improve your Rust code.
+//
+// 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` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 
+use std::f32;
+
 fn main() {
-    let x = 1.2331f64;
-    let y = 1.2332f64;
-    if y != x {
-        println!("Success!");
-    }
+    let pi = 3.14f32;
+    let radius = 5.00f32;
+
+    let area = pi * f32::powi(radius, 2);
+
+    println!(
+        "The area of a circle with radius {:.2} is {:.5}!",
+        radius, area
+    )
 }

exercises/clippy/clippy2.rs

@@ -1,5 +1,7 @@
 // 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 +1,30 @@
+// clippy3.rs
+// 
+// Here's a couple more easy Clippy fixes, so you can see its utility.
+// No hints.
+
+// 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/collections/README.md

@@ -1,20 +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.
-
-[Rust book chapter](https://doc.rust-lang.org/stable/book/ch08-01-vectors.html)

exercises/collections/vec2.rs

@@ -1,33 +0,0 @@
-// vec2.rs
-// A Vec of even numbers is given. Your task is to complete the loop
-// so that each number in the Vec is multiplied by 2.
-//
-// Make me pass the test!
-//
-// Execute the command `rustlings hint vec2` if you need
-// hints.
-
-// I AM NOT DONE
-
-fn vec_loop(mut v: Vec<i32>) -> Vec<i32> {
-    for i in v.iter_mut() {
-        // TODO: Fill this up so that each element in the Vec `v` is
-        // multiplied by 2.
-    }
-
-    // At this point, `v` should be equal to [4, 8, 12, 16, 20].
-    v
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_vec_loop() {
-        let v: Vec<i32> = (1..).filter(|x| x % 2 == 0).take(5).collect();
-        let ans = vec_loop(v.clone());
-
-        assert_eq!(ans, v.iter().map(|x| x * 2).collect::<Vec<i32>>());
-    }
-}

exercises/conversions/README.md

@@ -1,5 +1,4 @@
-### Type conversions
-
+# Type conversions
 
 Rust offers a multitude of ways to convert a value of a given type into another type.
 
@@ -7,6 +6,7 @@ The simplest form of type conversion is a type cast expression. It is denoted wi
 
 Rust also offers traits that facilitate type conversions upon implementation. These traits can be found under the [`convert`](https://doc.rust-lang.org/std/convert/index.html) module.
 The traits are the following:
+
 - `From` and `Into` covered in [`from_into`](from_into.rs)
 - `TryFrom` and `TryInto` covered in [`try_from_into`](try_from_into.rs)
 - `AsRef` and `AsMut` covered in [`as_ref_mut`](as_ref_mut.rs)
@@ -15,6 +15,9 @@ Furthermore, the `std::str` module offers a trait called [`FromStr`](https://doc
 
 These should be the main ways ***within the standard library*** to convert data into your desired types.
 
-#### Book Sections
+## Further information
 
-These are not directly covered in the book, but the standard library has great documentation for [conversions here](https://doc.rust-lang.org/std/convert/index.html). The `FromStr` trait is also covered [here](https://doc.rust-lang.org/std/str/trait.FromStr.html).
+These are not directly covered in the book, but the standard library has a great documentation for it.
+
+- [conversions](https://doc.rust-lang.org/std/convert/index.html)
+- [`FromStr` trait](https://doc.rust-lang.org/std/str/trait.FromStr.html)

exercises/conversions/as_ref_mut.rs

@@ -1,25 +1,31 @@
-// 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.
+// as_ref_mut.rs
+//
+// 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
 
-// Obtain the number of bytes (not characters) in the given argument
-// Add the AsRef trait appropriately as a trait bound
+// Obtain the number of bytes (not characters) in the given argument.
+// TODO: Add the AsRef trait appropriately as a trait bound.
 fn byte_counter<T>(arg: T) -> usize {
     arg.as_ref().as_bytes().len()
 }
 
-// Obtain the number of characters (not bytes) in the given argument
-// Add the AsRef trait appropriately as a trait bound
+// Obtain the number of characters (not bytes) in the given argument.
+// TODO: Add the AsRef trait appropriately as a trait bound.
 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 as_mut().
+// TODO: Add the appropriate trait bound.
+fn num_sq<T>(arg: &mut T) {
+    // TODO: Implement the function body.
+    ???
 }
 
 #[cfg(test)]
@@ -49,4 +55,11 @@ mod tests {
         let s = String::from("Cafe au lait");
         assert_eq!(char_counter(s.clone()), byte_counter(s));
     }
+
+    #[test]
+    fn mut_box() {
+        let mut num: Box<u32> = Box::new(3);
+        num_sq(&mut num);
+        assert_eq!(*num, 9);
+    }
 }

exercises/conversions/from_into.rs

@@ -1,6 +1,12 @@
-// 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
+// from_into.rs
+//
+// 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,
@@ -18,20 +24,21 @@ impl Default for Person {
     }
 }
 
-// Your task is to complete this implementation
-// in order for the line `let p = Person::from("Mark,20")` to compile
-// Please note that you'll need to parse the age component into a `usize`
-// with something like `"4".parse::<usize>()`. The outcome of this needs to
-// be handled appropriately.
+// Your task is to complete this implementation in order for the line `let p =
+// Person::from("Mark,20")` to compile Please note that you'll need to parse the
+// age component into a `usize` with something like `"4".parse::<usize>()`. The
+// outcome of this needs to be handled appropriately.
 //
 // Steps:
-// 1. If the length of the provided string is 0, then return the default of Person
-// 2. Split the given string on the commas present in it
-// 3. Extract the first element from the split operation and use it as the name
-// 4. If the name is empty, then return the default of Person
-// 5. Extract the other element from the split operation and parse it into a `usize` as the age
-// If while parsing the age, something goes wrong, then return the default of Person
-// Otherwise, then return an instantiated Person object with the results
+// 1. If the length of the provided string is 0, then return the default of
+//    Person.
+// 2. Split the given string on the commas present in it.
+// 3. Extract the first element from the split operation and use it as the name.
+// 4. If the name is empty, then return the default of Person.
+// 5. Extract the other element from the split operation and parse it into a
+//    `usize` as the age.
+// If while parsing the age, something goes wrong, then return the default of
+// Person Otherwise, then return an instantiated Person object with the results
 
 // I AM NOT DONE
 
@@ -75,7 +82,8 @@ mod tests {
     }
     #[test]
     fn test_bad_age() {
-        // Test that "Mark,twenty" will return the default person due to an error in parsing age
+        // Test that "Mark,twenty" will return the default person due to an
+        // error in parsing age
         let p = Person::from("Mark,twenty");
         assert_eq!(p.name, "John");
         assert_eq!(p.age, 30);
@@ -119,14 +127,14 @@ mod tests {
     #[test]
     fn test_trailing_comma() {
         let p: Person = Person::from("Mike,32,");
-        assert_eq!(p.name, "John");
-        assert_eq!(p.age, 30);
+        assert_eq!(p.name, "Mike");
+        assert_eq!(p.age, 32);
     }
 
     #[test]
     fn test_trailing_comma_and_some_string() {
         let p: Person = Person::from("Mike,32,man");
-        assert_eq!(p.name, "John");
-        assert_eq!(p.age, 30);
+        assert_eq!(p.name, "Mike");
+        assert_eq!(p.age, 32);
     }
 }

exercises/conversions/from_str.rs

@@ -1,30 +1,56 @@
-// This does practically the same thing that TryFrom<&str> does.
-// 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
-use std::error;
+// from_str.rs
+//
+// This is similar to from_into.rs, but this time we'll implement `FromStr` and
+// return errors instead of falling back to a default value. 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;
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 struct Person {
     name: String,
     age: usize,
 }
 
+// We will use this error type for the `FromStr` implementation.
+#[derive(Debug, PartialEq)]
+enum ParsePersonError {
+    // Empty input string
+    Empty,
+    // Incorrect number of fields
+    BadLen,
+    // Empty name field
+    NoName,
+    // Wrapped error from parse::<usize>()
+    ParseInt(ParseIntError),
+}
+
 // I AM NOT DONE
 
 // Steps:
 // 1. If the length of the provided string is 0, an error should be returned
 // 2. Split the given string on the commas present in it
-// 3. Only 2 elements should be returned from the split, otherwise return an error
+// 3. Only 2 elements should be returned from the split, otherwise return an
+//    error
 // 4. Extract the first element from the split operation and use it as the name
-// 5. Extract the other element from the split operation and parse it into a `usize` as the age
-//    with something like `"4".parse::<usize>()`
-// 5. If while extracting the name and the age something goes wrong, an error should be returned
+// 5. Extract the other element from the split operation and parse it into a
+//    `usize` as the age 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 = Box<dyn error::Error>;
+    type Err = ParsePersonError;
     fn from_str(s: &str) -> Result<Person, Self::Err> {
     }
 }
@@ -40,7 +66,7 @@ mod tests {
 
     #[test]
     fn empty_input() {
-        assert!("".parse::<Person>().is_err());
+        assert_eq!("".parse::<Person>(), Err(ParsePersonError::Empty));
     }
     #[test]
     fn good_input() {
@@ -52,41 +78,56 @@ mod tests {
     }
     #[test]
     fn missing_age() {
-        assert!("John,".parse::<Person>().is_err());
+        assert!(matches!(
+            "John,".parse::<Person>(),
+            Err(ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn invalid_age() {
-        assert!("John,twenty".parse::<Person>().is_err());
+        assert!(matches!(
+            "John,twenty".parse::<Person>(),
+            Err(ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn missing_comma_and_age() {
-        assert!("John".parse::<Person>().is_err());
+        assert_eq!("John".parse::<Person>(), Err(ParsePersonError::BadLen));
     }
 
     #[test]
     fn missing_name() {
-        assert!(",1".parse::<Person>().is_err());
+        assert_eq!(",1".parse::<Person>(), Err(ParsePersonError::NoName));
     }
 
     #[test]
     fn missing_name_and_age() {
-        assert!(",".parse::<Person>().is_err());
+        assert!(matches!(
+            ",".parse::<Person>(),
+            Err(ParsePersonError::NoName | ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn missing_name_and_invalid_age() {
-        assert!(",one".parse::<Person>().is_err());
+        assert!(matches!(
+            ",one".parse::<Person>(),
+            Err(ParsePersonError::NoName | ParsePersonError::ParseInt(_))
+        ));
     }
 
     #[test]
     fn trailing_comma() {
-        assert!("John,32,".parse::<Person>().is_err());
+        assert_eq!("John,32,".parse::<Person>(), Err(ParsePersonError::BadLen));
     }
 
     #[test]
     fn trailing_comma_and_some_string() {
-        assert!("John,32,man".parse::<Person>().is_err());
+        assert_eq!(
+            "John,32,man".parse::<Person>(),
+            Err(ParsePersonError::BadLen)
+        );
     }
 }

exercises/conversions/try_from_into.rs

@@ -1,9 +1,15 @@
-// TryFrom is a simple and safe type conversion that may fail in a controlled way under some circumstances.
-// 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
+// try_from_into.rs
+//
+// TryFrom is a simple and safe type conversion that may fail in a controlled
+// way under some circumstances. 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};
-use std::error;
 
 #[derive(Debug, PartialEq)]
 struct Color {
@@ -12,49 +18,60 @@ struct Color {
     blue: u8,
 }
 
+// We will use this error type for these `TryFrom` conversions.
+#[derive(Debug, PartialEq)]
+enum IntoColorError {
+    // Incorrect length of slice
+    BadLen,
+    // Integer conversion error
+    IntConversion,
+}
+
 // I AM NOT DONE
 
-// Your task is to complete this implementation
-// and return an Ok result of inner type Color.
-// You need to create an implementation for a tuple of three integers,
-// an array of three integers and a slice of integers.
+// Your task is to complete this implementation and return an Ok result of inner
+// type Color. You need to create an implementation for a tuple of three
+// integers, an array of three integers, and a slice of integers.
 //
-// Note that the implementation for tuple and array will be checked at compile time,
-// but the slice implementation needs to check the slice length!
-// Also note that correct RGB color values must be integers in the 0..=255 range.
+// Note that the implementation for tuple and array will be checked at compile
+// time, but the slice implementation needs to check the slice length! Also note
+// that correct RGB color values must be integers in the 0..=255 range.
 
 // Tuple implementation
 impl TryFrom<(i16, i16, i16)> for Color {
-    type Error = Box<dyn error::Error>;
-    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {}
+    type Error = IntoColorError;
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+    }
 }
 
 // Array implementation
 impl TryFrom<[i16; 3]> for Color {
-    type Error = Box<dyn error::Error>;
-    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {}
+    type Error = IntoColorError;
+    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+    }
 }
 
 // Slice implementation
 impl TryFrom<&[i16]> for Color {
-    type Error = Box<dyn error::Error>;
-    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {}
+    type Error = IntoColorError;
+    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+    }
 }
 
 fn main() {
-    // Use the `from` function
+    // Use the `try_from` function
     let c1 = Color::try_from((183, 65, 14));
     println!("{:?}", c1);
 
-    // Since From is implemented for Color, we should be able to use Into
+    // Since TryFrom is implemented for Color, we should be able to use TryInto
     let c2: Result<Color, _> = [183, 65, 14].try_into();
     println!("{:?}", c2);
 
     let v = vec![183, 65, 14];
-    // With slice we should use `from` function
+    // With slice we should use `try_from` function
     let c3 = Color::try_from(&v[..]);
     println!("{:?}", c3);
-    // or take slice within round brackets and use Into
+    // or take slice within round brackets and use TryInto
     let c4: Result<Color, _> = (&v[..]).try_into();
     println!("{:?}", c4);
 }
@@ -65,15 +82,24 @@ mod tests {
 
     #[test]
     fn test_tuple_out_of_range_positive() {
-        assert!(Color::try_from((256, 1000, 10000)).is_err());
+        assert_eq!(
+            Color::try_from((256, 1000, 10000)),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_tuple_out_of_range_negative() {
-        assert!(Color::try_from((-1, -10, -256)).is_err());
+        assert_eq!(
+            Color::try_from((-1, -10, -256)),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_tuple_sum() {
-        assert!(Color::try_from((-1, 255, 255)).is_err());
+        assert_eq!(
+            Color::try_from((-1, 255, 255)),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_tuple_correct() {
@@ -91,17 +117,17 @@ mod tests {
     #[test]
     fn test_array_out_of_range_positive() {
         let c: Result<Color, _> = [1000, 10000, 256].try_into();
-        assert!(c.is_err());
+        assert_eq!(c, Err(IntoColorError::IntConversion));
     }
     #[test]
     fn test_array_out_of_range_negative() {
         let c: Result<Color, _> = [-10, -256, -1].try_into();
-        assert!(c.is_err());
+        assert_eq!(c, Err(IntoColorError::IntConversion));
     }
     #[test]
     fn test_array_sum() {
         let c: Result<Color, _> = [-1, 255, 255].try_into();
-        assert!(c.is_err());
+        assert_eq!(c, Err(IntoColorError::IntConversion));
     }
     #[test]
     fn test_array_correct() {
@@ -119,17 +145,26 @@ mod tests {
     #[test]
     fn test_slice_out_of_range_positive() {
         let arr = [10000, 256, 1000];
-        assert!(Color::try_from(&arr[..]).is_err());
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_slice_out_of_range_negative() {
         let arr = [-256, -1, -10];
-        assert!(Color::try_from(&arr[..]).is_err());
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_slice_sum() {
         let arr = [-1, 255, 255];
-        assert!(Color::try_from(&arr[..]).is_err());
+        assert_eq!(
+            Color::try_from(&arr[..]),
+            Err(IntoColorError::IntConversion)
+        );
     }
     #[test]
     fn test_slice_correct() {
@@ -148,11 +183,11 @@ mod tests {
     #[test]
     fn test_slice_excess_length() {
         let v = vec![0, 0, 0, 0];
-        assert!(Color::try_from(&v[..]).is_err());
+        assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
     }
     #[test]
     fn test_slice_insufficient_length() {
         let v = vec![0, 0];
-        assert!(Color::try_from(&v[..]).is_err());
+        assert_eq!(Color::try_from(&v[..]), Err(IntoColorError::BadLen));
     }
 }

exercises/conversions/using_as.rs

@@ -1,14 +1,19 @@
-// Type casting in Rust is done via the usage of the `as` operator.
-// Please note that the `as` operator is not only used when type casting.
-// It also helps with renaming imports.
+// using_as.rs
 //
-// The goal is to make sure that the division does not fail to compile
-// and returns the proper type.
+// Type casting in Rust is done via the usage of the `as` operator. Please note
+// that the `as` operator is not only used when type casting. It also helps with
+// renaming imports.
+//
+// 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/README.md

@@ -1,10 +1,10 @@
-### Enums
+# Enums
 
 Rust allows you to define types called "enums" which enumerate possible values.
 Enums are a feature in many languages, but their capabilities differ in each language. Rust’s enums are most similar to algebraic data types in functional languages, such as F#, OCaml, and Haskell.
 Useful in combination with enums is Rust's "pattern matching" facility, which makes it easy to run different code for different values of an enumeration.
 
-#### Book Sections
+## Further information
 
 - [Enums](https://doc.rust-lang.org/book/ch06-00-enums.html)
 - [Pattern syntax](https://doc.rust-lang.org/book/ch18-03-pattern-syntax.html)

exercises/enums/enums1.rs

@@ -1,5 +1,6 @@
 // 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 +1,7 @@
 // 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
 
@@ -10,7 +12,7 @@ enum Message {
 
 impl Message {
     fn call(&self) {
-        println!("{:?}", &self);
+        println!("{:?}", self);
     }
 }
 

exercises/enums/enums3.rs

@@ -1,5 +1,9 @@
 // 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
 
@@ -16,6 +20,7 @@ struct State {
     color: (u8, u8, u8),
     position: Point,
     quit: bool,
+    message: String,
 }
 
 impl State {
@@ -27,8 +32,8 @@ impl State {
         self.quit = true;
     }
 
-    fn echo(&self, s: String) {
-        println!("{}", s);
+    fn echo(&mut self, s: String) {
+        self.message = s
     }
 
     fn move_position(&mut self, p: Point) {
@@ -37,6 +42,8 @@ impl State {
 
     fn process(&mut self, message: Message) {
         // TODO: create a match expression to process the different message variants
+        // Remember: When passing a tuple as a function argument, you'll need extra parentheses:
+        // fn function((t, u, p, l, e))
     }
 }
 
@@ -50,9 +57,10 @@ mod tests {
             quit: false,
             position: Point { x: 0, y: 0 },
             color: (0, 0, 0),
+            message: "hello world".to_string(),
         };
-        state.process(Message::ChangeColor((255, 0, 255)));
-        state.process(Message::Echo(String::from("hello world")));
+        state.process(Message::ChangeColor(255, 0, 255));
+        state.process(Message::Echo(String::from("Hello world!")));
         state.process(Message::Move(Point { x: 10, y: 15 }));
         state.process(Message::Quit);
 
@@ -60,5 +68,6 @@ mod tests {
         assert_eq!(state.position.x, 10);
         assert_eq!(state.position.y, 15);
         assert_eq!(state.quit, true);
+        assert_eq!(state.message, "Hello world!");
     }
 }

exercises/error_handling/README.md

@@ -1,5 +1,12 @@
-For this exercise check out the sections:
+# Error handling
+
+Most errors aren’t serious enough to require the program to stop entirely.
+Sometimes, when a function fails, it’s for a reason that you can easily interpret and respond to.
+For example, if you try to open a file and that operation fails because the file doesn’t exist, you might want to create the file instead of terminating the process.
+
+## Further information
+
 - [Error Handling](https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html)
 - [Generics](https://doc.rust-lang.org/book/ch10-01-syntax.html)
-
-of the Rust Book.
+- [Result](https://doc.rust-lang.org/rust-by-example/error/result.html)
+- [Boxing errors](https://doc.rust-lang.org/rust-by-example/error/multiple_error_types/boxing_errors.html)

exercises/error_handling/errors1.rs

@@ -1,19 +1,22 @@
 // errors1.rs
-// This function refuses to generate text to be printed on a nametag if
-// you pass it an empty string. It'd be nicer if it explained what the problem
-// was, instead of just sometimes returning `None`. The 2nd test currently
-// does not compile or pass, but it illustrates the behavior we would like
-// this function to have.
-// Execute `rustlings hint errors1` for hints!
+//
+// This function refuses to generate text to be printed on a nametag if 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` 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))
     }
 }
 
@@ -21,14 +24,11 @@ pub fn generate_nametag_text(name: String) -> Option<String> {
 mod tests {
     use super::*;
 
-    // This test passes initially if you comment out the 2nd test.
-    // You'll need to update what this test expects when you change
-    // the function under test!
     #[test]
     fn generates_nametag_text_for_a_nonempty_name() {
         assert_eq!(
             generate_nametag_text("Beyoncé".into()),
-            Some("Hi! My name is Beyoncé".into())
+            Ok("Hi! My name is Beyoncé".into())
         );
     }
 
@@ -36,6 +36,7 @@ mod tests {
     fn explains_why_generating_nametag_text_fails() {
         assert_eq!(
             generate_nametag_text("".into()),
+            // Don't change this line
             Err("`name` was empty; it must be nonempty.".into())
         );
     }

exercises/error_handling/errors2.rs

@@ -1,20 +1,23 @@
 // errors2.rs
+//
 // Say we're writing a game where you can buy items with tokens. All items cost
 // 5 tokens, and whenever you purchase items there is a processing fee of 1
-// token. A player of the game will type in how many items they want to buy,
-// and the `total_cost` function will calculate the total number of tokens.
-// Since the player typed in the quantity, though, we get it as a string-- and
-// they might have typed anything, not just numbers!
-
+// token. A player of the game will type in how many items they want to buy, and
+// the `total_cost` function will calculate the total cost of the tokens. Since
+// the player typed in the quantity, though, we get it as a string-- and they
+// might have typed anything, not just numbers!
+//
 // Right now, this function isn't handling the error case at all (and isn't
-// handling the success case properly either). What we want to do is:
-// if we call the `parse` function on a string that is not a number, that
-// function will return a `ParseIntError`, and in that case, we want to
-// immediately return that error from our function and not try to multiply
-// 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.
+// handling the success case properly either). What we want to do is: if we call
+// the `total_cost` function on a string that is not a number, that function
+// will return a `ParseIntError`, and in that case, we want to immediately
+// return that error from our function and not try to multiply 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` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 

exercises/error_handling/errors3.rs

@@ -1,8 +1,11 @@
 // errors3.rs
+//
 // 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 +1,7 @@
-// result1.rs
-// Make this test pass! Execute `rustlings hint result1` for hints :)
+// errors4.rs
+//
+// Execute `rustlings hint errors4` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 
@@ -14,6 +16,7 @@ enum CreationError {
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
+        // Hmm... Why is this always returning an Ok value?
         Ok(PositiveNonzeroInteger(value as u64))
     }
 }

exercises/error_handling/errors5.rs

@@ -0,0 +1,71 @@
+// errors5.rs
+//
+// 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
+
+use std::error;
+use std::fmt;
+use std::num::ParseIntError;
+
+// TODO: update the return type of `main()` to make this compile.
+fn main() -> Result<(), Box<dyn ???>> {
+    let pretend_user_input = "42";
+    let x: i64 = pretend_user_input.parse()?;
+    println!("output={:?}", PositiveNonzeroInteger::new(x)?);
+    Ok(())
+}
+
+// Don't change anything below this line.
+
+#[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)),
+        }
+    }
+}
+
+// This is required so that `CreationError` can implement `error::Error`.
+impl fmt::Display for CreationError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let description = match *self {
+            CreationError::Negative => "number is negative",
+            CreationError::Zero => "number is zero",
+        };
+        f.write_str(description)
+    }
+}
+
+impl error::Error for CreationError {}

exercises/error_handling/errors6.rs

@@ -0,0 +1,94 @@
+// errors6.rs
+//
+// Using catch-all error types like `Box<dyn error::Error>` isn't recommended
+// for library code, where callers might want to make decisions based on the
+// error content, instead of printing it out or propagating it further. Here, we
+// define a custom error type to make it possible for callers to decide what to
+// do next when our function returns an error.
+//
+// Execute `rustlings hint errors6` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+use std::num::ParseIntError;
+
+// This is a custom error type that we will be using in `parse_pos_nonzero()`.
+#[derive(PartialEq, Debug)]
+enum ParsePosNonzeroError {
+    Creation(CreationError),
+    ParseInt(ParseIntError),
+}
+
+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) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
+    // TODO: change this to return an appropriate error instead of panicking
+    // when `parse()` returns an error.
+    let x: i64 = s.parse().unwrap();
+    PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
+}
+
+// Don't change anything below this line.
+
+#[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!(
+            parse_pos_nonzero("not a number"),
+            Err(ParsePosNonzeroError::ParseInt(_))
+        ));
+    }
+
+    #[test]
+    fn test_negative() {
+        assert_eq!(
+            parse_pos_nonzero("-555"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Negative))
+        );
+    }
+
+    #[test]
+    fn test_zero() {
+        assert_eq!(
+            parse_pos_nonzero("0"),
+            Err(ParsePosNonzeroError::Creation(CreationError::Zero))
+        );
+    }
+
+    #[test]
+    fn test_positive() {
+        let x = PositiveNonzeroInteger::new(42);
+        assert!(x.is_ok());
+        assert_eq!(parse_pos_nonzero("42"), Ok(x.unwrap()));
+    }
+}

exercises/error_handling/errorsn.rs

@@ -1,117 +0,0 @@
-// errorsn.rs
-// This is a bigger error exercise than the previous ones!
-// You can do it! :)
-//
-// Edit the `read_and_validate` function ONLY. Don't create any Errors
-// that do not already exist.
-//
-// So many things could go wrong!
-//
-// - Reading from stdin could produce an io::Error
-// - Parsing the input could produce a num::ParseIntError
-// - Validating the input could produce a CreationError (defined below)
-//
-// How can we lump these errors into one general error? That is, what
-// type goes where the question marks are, and how do we return
-// that type from the body of read_and_validate?
-//
-// Execute `rustlings hint errorsn` for hints :)
-
-// I AM NOT DONE
-
-use std::error;
-use std::fmt;
-use std::io;
-
-// PositiveNonzeroInteger is a struct defined below the tests.
-fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger, ???> {
-    let mut line = String::new();
-    b.read_line(&mut line);
-    let num: i64 = line.trim().parse();
-    let answer = PositiveNonzeroInteger::new(num);
-    answer
-}
-
-//
-// Nothing below this needs to be modified
-//
-
-// This is a test helper function that turns a &str into a BufReader.
-fn test_with_str(s: &str) -> Result<PositiveNonzeroInteger, Box<dyn error::Error>> {
-    let mut b = io::BufReader::new(s.as_bytes());
-    read_and_validate(&mut b)
-}
-
-#[test]
-fn test_success() {
-    let x = test_with_str("42\n");
-    assert_eq!(PositiveNonzeroInteger(42), x.unwrap());
-}
-
-#[test]
-fn test_not_num() {
-    let x = test_with_str("eleven billion\n");
-    assert!(x.is_err());
-}
-
-#[test]
-fn test_non_positive() {
-    let x = test_with_str("-40\n");
-    assert!(x.is_err());
-}
-
-#[test]
-fn test_ioerror() {
-    struct Broken;
-    impl io::Read for Broken {
-        fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
-            Err(io::Error::new(io::ErrorKind::BrokenPipe, "uh-oh!"))
-        }
-    }
-    let mut b = io::BufReader::new(Broken);
-    assert!(read_and_validate(&mut b).is_err());
-    assert_eq!("uh-oh!", read_and_validate(&mut b).unwrap_err().to_string());
-}
-
-#[derive(PartialEq, Debug)]
-struct PositiveNonzeroInteger(u64);
-
-impl PositiveNonzeroInteger {
-    fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
-        if value == 0 {
-            Err(CreationError::Zero)
-        } else if value < 0 {
-            Err(CreationError::Negative)
-        } else {
-            Ok(PositiveNonzeroInteger(value as u64))
-        }
-    }
-}
-
-#[test]
-fn test_positive_nonzero_integer_creation() {
-    assert!(PositiveNonzeroInteger::new(10).is_ok());
-    assert_eq!(
-        Err(CreationError::Negative),
-        PositiveNonzeroInteger::new(-10)
-    );
-    assert_eq!(Err(CreationError::Zero), PositiveNonzeroInteger::new(0));
-}
-
-#[derive(PartialEq, Debug)]
-enum CreationError {
-    Negative,
-    Zero,
-}
-
-impl fmt::Display for CreationError {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        let description = match *self {
-            CreationError::Negative => "Number is negative",
-            CreationError::Zero => "Number is zero",
-        };
-        f.write_str(description)
-    }
-}
-
-impl error::Error for CreationError {}

exercises/functions/README.md

@@ -1,7 +1,8 @@
-### Functions
+# 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.
 
-#### Book Sections
+## Further information
 
 - [How Functions Work](https://doc.rust-lang.org/book/ch03-03-how-functions-work.html)

exercises/functions/functions1.rs

@@ -1,5 +1,7 @@
 // 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 +1,7 @@
 // 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 +1,7 @@
 // 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 +1,12 @@
 // functions4.rs
-// Make me compile! Execute `rustlings hint functions4` for hints :)
-
-// 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.
+//
+// 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!)
+//
+// Execute `rustlings hint functions4` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 

exercises/functions/functions5.rs

@@ -1,11 +1,13 @@
 // 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/generics/README.md

@@ -1,7 +1,11 @@
-### Generics
+# Generics
 
-In this section you'll learn about saving yourself many lines of code with generics!
+Generics is the topic of generalizing types and functionalities to broader cases.
+This is extremely useful for reducing code duplication in many ways, but can call for rather involving syntax.
+Namely, being generic requires taking great care to specify over which types a generic type is actually considered valid.
+The simplest and most common use of generics is for type parameters.
 
-### Book Sections
+## Further information
 
 - [Generic Data Types](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html)
+- [Bounds](https://doc.rust-lang.org/rust-by-example/generics/bounds.html)

exercises/generics/generics1.rs

@@ -1,5 +1,10 @@
-// This shopping list program isn't compiling!
-// Use your knowledge of generics to fix it.
+// generics1.rs
+//
+// This shopping list program isn't compiling! Use your knowledge of generics to
+// fix it.
+//
+// Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 

exercises/generics/generics2.rs

@@ -1,5 +1,10 @@
+// generics2.rs
+//
 // 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` 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/hashmaps/README.md

@@ -0,0 +1,12 @@
+# 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

@@ -1,15 +1,15 @@
-// hashmap1.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
-// at least three different types of fruits (e.g apple, banana, mango)
-// in the basket and the total count of all the fruits should be at
-// least five.
+// 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 at least three different
+// types of fruits (e.g apple, banana, mango) in the basket and the total count
+// of all the fruits should be at least five.
 //
 // 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

@@ -1,16 +1,18 @@
-// hashmap2.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
-// of that particular fruit is in the basket. You have to put *MORE
-// THAN 11* fruits in the basket. Three types of fruits - Apple (4),
-// Mango (2) and Lychee (5) are already given in the basket. You are
-// not allowed to insert any more of these fruits!
+// hashmaps2.rs
+//
+// We're collecting different fruits to bake a delicious fruit cake. For this,
+// we have a basket, which we'll represent in the form of a hash map. The key
+// represents the name of each fruit we collect and the value represents how
+// many of that particular fruit we have collected. Three types of fruits -
+// Apple (4), Mango (2) and Lychee (5) are already in the basket hash map. You
+// must add fruit to the basket so that there is at least one of each kind and
+// more than 11 in total - we have a lot of mouths to feed. You are not allowed
+// to insert any more of these fruits!
 //
 // 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
 
@@ -35,9 +37,9 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
     ];
 
     for fruit in fruit_kinds {
-        // TODO: Put new fruits if not already present. Note that you
-        // are not allowed to put any type of fruit that's already
-        // present!
+        // TODO: Insert new fruits if they are not already present in the
+        // basket. Note that you are not allowed to put any type of fruit that's
+        // already present!
     }
 }
 
@@ -45,6 +47,7 @@ fn fruit_basket(basket: &mut HashMap<Fruit, u32>) {
 mod tests {
     use super::*;
 
+    // Don't modify this function!
     fn get_fruit_basket() -> HashMap<Fruit, u32> {
         let mut basket = HashMap::<Fruit, u32>::new();
         basket.insert(Fruit::Apple, 4);
@@ -78,4 +81,13 @@ mod tests {
         let count = basket.values().sum::<u32>();
         assert!(count > 11);
     }
+    
+    #[test]
+    fn all_fruit_types_in_basket() {
+        let mut basket = get_fruit_basket();
+        fruit_basket(&mut basket);
+        for amount in basket.values() {
+            assert_ne!(amount, &0);
+        }
+    }
 }

exercises/hashmaps/hashmaps3.rs

@@ -0,0 +1,86 @@
+// 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 the goal details of a team.
+struct Team {
+    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 the 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

@@ -1,7 +1,7 @@
-### If
+# 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.
 
-#### Book Sections
+## Further information
 
 - [Control Flow - if expressions](https://doc.rust-lang.org/book/ch03-05-control-flow.html#if-expressions)

exercises/if/if1.rs

@@ -1,4 +1,6 @@
 // if1.rs
+//
+// Execute `rustlings hint if1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -7,7 +9,6 @@ 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 :)
@@ -24,4 +25,9 @@ mod tests {
     fn fortytwo_is_bigger_than_thirtytwo() {
         assert_eq!(42, bigger(32, 42));
     }
+
+    #[test]
+    fn equal_numbers() {
+        assert_eq!(42, bigger(42, 42));
+    }
 }

exercises/if/if2.rs

@@ -1,12 +1,13 @@
 // if2.rs
-
+//
 // 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 +22,16 @@ 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/if3.rs

@@ -0,0 +1,56 @@
+// if3.rs
+//
+// Execute `rustlings hint if3` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+pub fn animal_habitat(animal: &str) -> &'static str {
+    let identifier = if animal == "crab" {
+        1
+    } else if animal == "gopher" {
+        2.0
+    } else if animal == "snake" {
+        3
+    } else {
+        "Unknown"
+    };
+
+    // DO NOT CHANGE THIS STATEMENT BELOW
+    let habitat = if identifier == 1 {
+        "Beach"
+    } else if identifier == 2 {
+        "Burrow"
+    } else if identifier == 3 {
+        "Desert"
+    } else {
+        "Unknown"
+    };
+
+    habitat
+}
+
+// No test changes needed.
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn gopher_lives_in_burrow() {
+        assert_eq!(animal_habitat("gopher"), "Burrow")
+    }
+
+    #[test]
+    fn snake_lives_in_desert() {
+        assert_eq!(animal_habitat("snake"), "Desert")
+    }
+
+    #[test]
+    fn crab_lives_on_beach() {
+        assert_eq!(animal_habitat("crab"), "Beach")
+    }
+
+    #[test]
+    fn unknown_animal() {
+        assert_eq!(animal_habitat("dinosaur"), "Unknown")
+    }
+}

exercises/intro/README.md

@@ -0,0 +1,8 @@
+# Intro
+
+Rust uses the `print!` and `println!` macros to print text to the console.
+
+## Further information
+
+- [Hello World](https://doc.rust-lang.org/rust-by-example/hello.html)
+- [Formatted print](https://doc.rust-lang.org/rust-by-example/hello/print.html)

exercises/intro/intro1.rs

@@ -0,0 +1,41 @@
+// intro1.rs
+//
+// About this `I AM NOT DONE` thing:
+// 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.
+//
+// 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!
+//
+// Execute `rustlings hint intro1` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+fn main() {
+    println!("Hello and");
+    println!(r#"       welcome to...                      "#);
+    println!(r#"                 _   _ _                  "#);
+    println!(r#"  _ __ _   _ ___| |_| (_)_ __   __ _ ___  "#);
+    println!(r#" | '__| | | / __| __| | | '_ \ / _` / __| "#);
+    println!(r#" | |  | |_| \__ \ |_| | | | | | (_| \__ \ "#);
+    println!(r#" |_|   \__,_|___/\__|_|_|_| |_|\__, |___/ "#);
+    println!(r#"                               |___/      "#);
+    println!();
+    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."
+    );
+    println!();
+    println!(
+        "If you want to use rust-analyzer, Rust's LSP implementation, make sure your editor is set"
+    );
+    println!("up, and then run `rustlings lsp` before continuing.")
+}

exercises/intro/intro2.rs

@@ -0,0 +1,12 @@
+// intro2.rs
+//
+// Make the code print a greeting to the world.
+//
+// Execute `rustlings hint intro2` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+fn main() {
+    println!("Hello {}!");
+}

exercises/iterators/README.md

@@ -0,0 +1,8 @@
+# Iterators
+
+This section will teach you about Iterators.
+
+## Further information
+
+- [Iterator](https://doc.rust-lang.org/book/ch13-02-iterators.html)
+- [Iterator documentation](https://doc.rust-lang.org/stable/std/iter/)

exercises/iterators/iterators1.rs

@@ -1,16 +1,18 @@
 // iterators1.rs
 //
-//  Make me compile by filling in the `???`s
+// When performing operations on elements within a collection, iterators are
+// essential. This module helps you get familiar with the structure of using an
+// iterator and how to go through elements within an iterable collection.
 //
-// When performing operations on elements within a collection, iterators are essential.
-// This module helps you get familiar with the structure of using an iterator and 
-// how to go through elements within an iterable collection.
+// Make me compile by filling in the `???`s
 //
-// Execute `rustlings hint iterators1` for hints :D
+// Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 
-fn main () {
+#[test]
+fn main() {
     let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
 
     let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
@@ -18,7 +20,7 @@ fn main () {
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
     assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2.1
-    assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
     assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
+    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 4
 }

exercises/iterators/iterators2.rs

@@ -0,0 +1,63 @@
+// iterators2.rs
+//
+// In this exercise, you'll learn some of the unique advantages that iterators
+// can offer. Follow the steps to complete the exercise.
+//
+// Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+// Step 1.
+// Complete the `capitalize_first` function.
+// "hello" -> "Hello"
+pub fn capitalize_first(input: &str) -> String {
+    let mut c = input.chars();
+    match c.next() {
+        None => String::new(),
+        Some(first) => ???,
+    }
+}
+
+// Step 2.
+// Apply the `capitalize_first` function to a slice of string slices.
+// Return a vector of strings.
+// ["hello", "world"] -> ["Hello", "World"]
+pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
+    vec![]
+}
+
+// Step 3.
+// Apply the `capitalize_first` function again to a slice of string slices.
+// Return a single string.
+// ["hello", " ", "world"] -> "Hello World"
+pub fn capitalize_words_string(words: &[&str]) -> String {
+    String::new()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_success() {
+        assert_eq!(capitalize_first("hello"), "Hello");
+    }
+
+    #[test]
+    fn test_empty() {
+        assert_eq!(capitalize_first(""), "");
+    }
+
+    #[test]
+    fn test_iterate_string_vec() {
+        let words = vec!["hello", "world"];
+        assert_eq!(capitalize_words_vector(&words), ["Hello", "World"]);
+    }
+
+    #[test]
+    fn test_iterate_into_string() {
+        let words = vec!["hello", " ", "world"];
+        assert_eq!(capitalize_words_string(&words), "Hello World");
+    }
+}

exercises/iterators/iterators3.rs

@@ -0,0 +1,90 @@
+// iterators3.rs
+//
+// This is a bigger exercise than most of the others! You can do it! Here is
+// your mission, should you choose to accept it:
+// 1. Complete the divide function to get the first four tests to pass.
+// 2. Get the remaining tests to pass by completing the result_with_list and
+//    list_of_results functions.
+//
+// Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum DivisionError {
+    NotDivisible(NotDivisibleError),
+    DivideByZero,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct NotDivisibleError {
+    dividend: i32,
+    divisor: i32,
+}
+
+// Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
+// Otherwise, return a suitable error.
+pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
+    todo!();
+}
+
+// Complete the function and return a value of the correct type so the test
+// passes.
+// Desired output: Ok([1, 11, 1426, 3])
+fn result_with_list() -> () {
+    let numbers = vec![27, 297, 38502, 81];
+    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+}
+
+// Complete the function and return a value of the correct type so the test
+// passes.
+// Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
+fn list_of_results() -> () {
+    let numbers = vec![27, 297, 38502, 81];
+    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_success() {
+        assert_eq!(divide(81, 9), Ok(9));
+    }
+
+    #[test]
+    fn test_not_divisible() {
+        assert_eq!(
+            divide(81, 6),
+            Err(DivisionError::NotDivisible(NotDivisibleError {
+                dividend: 81,
+                divisor: 6
+            }))
+        );
+    }
+
+    #[test]
+    fn test_divide_by_0() {
+        assert_eq!(divide(81, 0), Err(DivisionError::DivideByZero));
+    }
+
+    #[test]
+    fn test_divide_0_by_something() {
+        assert_eq!(divide(0, 81), Ok(0));
+    }
+
+    #[test]
+    fn test_result_with_list() {
+        assert_eq!(format!("{:?}", result_with_list()), "Ok([1, 11, 1426, 3])");
+    }
+
+    #[test]
+    fn test_list_of_results() {
+        assert_eq!(
+            format!("{:?}", list_of_results()),
+            "[Ok(1), Ok(11), Ok(1426), Ok(3)]"
+        );
+    }
+}

exercises/iterators/iterators4.rs

@@ -1,4 +1,7 @@
 // iterators4.rs
+//
+// Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 
@@ -18,6 +21,11 @@ pub fn factorial(num: u64) -> u64 {
 mod tests {
     use super::*;
 
+    #[test]
+    fn factorial_of_0() {
+        assert_eq!(1, factorial(0));
+    }
+
     #[test]
     fn factorial_of_1() {
         assert_eq!(1, factorial(1));

exercises/iterators/iterators5.rs

@@ -0,0 +1,156 @@
+// iterators5.rs
+//
+// Let's define a simple model to track Rustlings exercise progress. Progress
+// will be modelled using a hash map. The name of the exercise is the key and
+// the progress is the value. Two counting functions were created to count the
+// number of exercises with a given progress. Recreate this counting
+// functionality using iterators. Try not to use imperative loops (for, while).
+// Only the two iterator methods (count_iterator and count_collection_iterator)
+// need to be modified.
+//
+// Execute `rustlings hint iterators5` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+enum Progress {
+    None,
+    Some,
+    Complete,
+}
+
+fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
+    let mut count = 0;
+    for val in map.values() {
+        if val == &value {
+            count += 1;
+        }
+    }
+    count
+}
+
+fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
+    // map is a hashmap with String keys and Progress values.
+    // map = { "variables1": Complete, "from_str": None, ... }
+    todo!();
+}
+
+fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
+    let mut count = 0;
+    for map in collection {
+        for val in map.values() {
+            if val == &value {
+                count += 1;
+            }
+        }
+    }
+    count
+}
+
+fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
+    // collection is a slice of hashmaps.
+    // collection = [{ "variables1": Complete, "from_str": None, ... },
+    //     { "variables2": Complete, ... }, ... ]
+    todo!();
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn count_complete() {
+        let map = get_map();
+        assert_eq!(3, count_iterator(&map, Progress::Complete));
+    }
+
+    #[test]
+    fn count_some() {
+        let map = get_map();
+        assert_eq!(1, count_iterator(&map, Progress::Some));
+    }
+
+    #[test]
+    fn count_none() {
+        let map = get_map();
+        assert_eq!(2, count_iterator(&map, Progress::None));
+    }
+
+    #[test]
+    fn count_complete_equals_for() {
+        let map = get_map();
+        let progress_states = vec![Progress::Complete, Progress::Some, Progress::None];
+        for progress_state in progress_states {
+            assert_eq!(
+                count_for(&map, progress_state),
+                count_iterator(&map, progress_state)
+            );
+        }
+    }
+
+    #[test]
+    fn count_collection_complete() {
+        let collection = get_vec_map();
+        assert_eq!(
+            6,
+            count_collection_iterator(&collection, Progress::Complete)
+        );
+    }
+
+    #[test]
+    fn count_collection_some() {
+        let collection = get_vec_map();
+        assert_eq!(1, count_collection_iterator(&collection, Progress::Some));
+    }
+
+    #[test]
+    fn count_collection_none() {
+        let collection = get_vec_map();
+        assert_eq!(4, count_collection_iterator(&collection, Progress::None));
+    }
+
+    #[test]
+    fn count_collection_equals_for() {
+        let progress_states = vec![Progress::Complete, Progress::Some, Progress::None];
+        let collection = get_vec_map();
+
+        for progress_state in progress_states {
+            assert_eq!(
+                count_collection_for(&collection, progress_state),
+                count_collection_iterator(&collection, progress_state)
+            );
+        }
+    }
+
+    fn get_map() -> HashMap<String, Progress> {
+        use Progress::*;
+
+        let mut map = HashMap::new();
+        map.insert(String::from("variables1"), Complete);
+        map.insert(String::from("functions1"), Complete);
+        map.insert(String::from("hashmap1"), Complete);
+        map.insert(String::from("arc1"), Some);
+        map.insert(String::from("as_ref_mut"), None);
+        map.insert(String::from("from_str"), None);
+
+        map
+    }
+
+    fn get_vec_map() -> Vec<HashMap<String, Progress>> {
+        use Progress::*;
+
+        let map = get_map();
+
+        let mut other = HashMap::new();
+        other.insert(String::from("variables2"), Complete);
+        other.insert(String::from("functions2"), Complete);
+        other.insert(String::from("if1"), Complete);
+        other.insert(String::from("from_into"), None);
+        other.insert(String::from("try_from_into"), None);
+
+        vec![map, other]
+    }
+}

exercises/lifetimes/README.md

@@ -0,0 +1,22 @@
+# 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.
+
+If you'd like to learn more about lifetime annotations, the
+[lifetimekata](https://tfpk.github.io/lifetimekata/) project
+has a similar style of exercises to Rustlings, but is all about
+learning to write lifetime annotations.
+
+## Further information
+
+- [Lifetimes (in Rust By Example)](https://doc.rust-lang.org/stable/rust-by-example/scope/lifetime.html)
+- [Validating References with Lifetimes](https://doc.rust-lang.org/book/ch10-03-lifetime-syntax.html)

exercises/lifetimes/lifetimes1.rs

@@ -0,0 +1,27 @@
+// 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 +1,21 @@
+// 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

@@ -1,10 +1,14 @@
-### Macros
+# Macros
 
 Rust's macro system is very powerful, but also kind of difficult to wrap your
 head around. We're not going to teach you how to write your own fully-featured
 macros. Instead, we'll show you how to use and create them.
 
-#### Book Sections
+If you'd like to learn more about writing your own macros, the
+[macrokata](https://github.com/tfpk/macrokata) project has a similar style
+of exercises to Rustlings, but is all about learning to write Macros.
+
+## 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 +1,7 @@
 // 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 +1,7 @@
 // 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 +1,9 @@
 // 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

@@ -1,8 +1,11 @@
 // 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
 
+#[rustfmt::skip]
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");

exercises/modules/README.md

@@ -1,7 +1,7 @@
-### Modules
+# Modules
 
 In this section we'll give you an introduction to Rust's module system.
 
-#### Book Sections
+## Further information
 
-- [The Module System](https://doc.rust-lang.org/book/ch07-02-defining-modules-to-control-scope-and-privacy.html)
+- [The Module System](https://doc.rust-lang.org/book/ch07-00-managing-growing-projects-with-packages-crates-and-modules.html)

exercises/modules/modules1.rs

@@ -1,10 +1,18 @@
 // 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
 
 mod sausage_factory {
+    // Don't let anybody outside of this module see this!
+    fn get_secret_recipe() -> String {
+        String::from("Ginger")
+    }
+
     fn make_sausage() {
+        get_secret_recipe();
         println!("sausage!");
     }
 }

exercises/modules/modules2.rs

@@ -1,11 +1,18 @@
 // modules2.rs
-// Make me compile! Execute `rustlings hint modules2` for hints :)
+//
+// 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.
+//
+// Execute `rustlings hint modules2` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 
 mod delicious_snacks {
-    use self::fruits::PEAR as fruit;
-    use self::veggies::CUCUMBER as veggie;
+    // TODO: Fix these use statements
+    use self::fruits::PEAR as ???
+    use self::veggies::CUCUMBER as ???
 
     mod fruits {
         pub const PEAR: &'static str = "Pear";

exercises/modules/modules3.rs

@@ -0,0 +1,21 @@
+// modules3.rs
+//
+// You can use the 'use' keyword to bring module paths from modules from
+// anywhere 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!
+//
+// Execute `rustlings hint modules3` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+// TODO: Complete this use statement
+use ???
+
+fn main() {
+    match SystemTime::now().duration_since(UNIX_EPOCH) {
+        Ok(n) => println!("1970-01-01 00:00:00 UTC was {} seconds ago!", n.as_secs()),
+        Err(_) => panic!("SystemTime before UNIX EPOCH!"),
+    }
+}

exercises/move_semantics/README.md

@@ -1,8 +1,8 @@
-### Move Semantics
+# Move Semantics
 
 These exercises are adapted from [pnkfelix](https://github.com/pnkfelix)'s [Rust Tutorial](https://pnkfelix.github.io/rust-examples-icfp2014/) -- Thank you Felix!!!
 
-#### Book Sections
+## Further information
 
 For this section, the book links are especially important.
 

exercises/move_semantics/move_semantics1.rs

@@ -1,26 +1,23 @@
 // 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
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let vec1 = fill_vec(vec0);
 
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
-
-    vec1.push(88);
-
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
+    let vec = vec;
 
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

exercises/move_semantics/move_semantics2.rs

@@ -1,28 +1,26 @@
 // move_semantics2.rs
-// Make me compile without changing line 13!
-// Execute `rustlings hint move_semantics2` for hints :)
+//
+// Make the test pass by finding a way to keep both Vecs separate!
+//
+// Execute `rustlings hint move_semantics2` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let mut vec1 = fill_vec(vec0);
 
-    // Do not change the following line!
-    println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0);
-
-    vec1.push(88);
-
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec0, vec![22, 44, 66]);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
     let mut vec = vec;
 
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

exercises/move_semantics/move_semantics3.rs

@@ -1,26 +1,24 @@
 // 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 :)
+//
+// Make me compile without adding new lines -- just changing existing lines! (no
+// lines with multiple semicolons necessary!)
+//
+// Execute `rustlings hint move_semantics3` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let mut vec1 = fill_vec(vec0);
 
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
-
-    vec1.push(88);
-
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
 fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

exercises/move_semantics/move_semantics4.rs

@@ -1,30 +1,29 @@
 // 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
 
+#[test]
 fn main() {
-    let vec0 = Vec::new();
+    let vec0 = vec![22, 44, 66];
 
     let mut vec1 = fill_vec(vec0);
 
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
-
-    vec1.push(88);
-
-    println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
+    assert_eq!(vec1, vec![22, 44, 66, 88]);
 }
 
-// `fill_vec()` no longer takes `vec: Vec<i32>` as argument
+// `fill_vec()` no longer takes `vec: Vec<i32>` as argument - don't change this!
 fn fill_vec() -> Vec<i32> {
+    // Instead, let's create and fill the Vec in here - how do you do that?
     let mut vec = vec;
 
-    vec.push(22);
-    vec.push(44);
-    vec.push(66);
+    vec.push(88);
 
     vec
 }

exercises/move_semantics/move_semantics5.rs

@@ -0,0 +1,19 @@
+// 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` or use the `hint` watch subcommand
+// for a hint.
+
+// I AM NOT DONE
+
+#[test]
+fn main() {
+    let mut x = 100;
+    let y = &mut x;
+    let z = &mut x;
+    *y += 100;
+    *z += 1000;
+    assert_eq!(x, 1200);
+}

exercises/move_semantics/move_semantics6.rs

@@ -0,0 +1,28 @@
+// move_semantics6.rs
+//
+// You can't change anything except adding or removing references.
+//
+// Execute `rustlings hint move_semantics6` or use the `hint` watch subcommand
+// for a hint.
+
+// I AM NOT DONE
+
+fn main() {
+    let data = "Rust is great!".to_string();
+
+    get_char(data);
+
+    string_uppercase(&data);
+}
+
+// Should not take ownership
+fn get_char(data: String) -> char {
+    data.chars().last().unwrap()
+}
+
+// Should take ownership
+fn string_uppercase(mut data: &String) {
+    data = &data.to_uppercase();
+
+    println!("{}", data);
+}

exercises/option/README.md

@@ -1,9 +0,0 @@
-### Option
-
-#### Book Sections
-
-To learn about Option<T>, check out these links:
-
-- [Option Enum Format](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-enum-definitions)
-- [Option Module Documentation](https://doc.rust-lang.org/std/option/)
-- [Option Enum Documentation](https://doc.rust-lang.org/std/option/enum.Option.html)

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 sig
-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/option/option2.rs

@@ -1,25 +0,0 @@
-// option2.rs
-// Make me compile! Execute `rustlings hint option2` for hints
-
-// I AM NOT DONE
-
-fn main() {
-    let optional_word = Some(String::from("rustlings"));
-    // TODO: Make this an if let statement whose value is "Some" type
-    word = optional_word {
-        println!("The word is: {}", word);
-    } else {
-        println!("The optional word doesn't contain anything");
-    }
-
-    let mut optional_integers_vec: Vec<Option<i8>> = Vec::new();
-    for x in 1..10 {
-        optional_integers_vec.push(Some(x));
-    }
-
-    // TODO: make this a while let statement - remember that vector.pop also adds another layer of Option<T>
-    // You can stack `Option<T>`'s into while let and if let
-    integer = optional_integers_vec.pop() {
-        println!("current value: {}", integer);
-    }
-}

exercises/options/README.md

@@ -0,0 +1,21 @@
+# 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:
+
+- Initial values
+- Return values for functions that are not defined over their entire input range (partial functions)
+- Return value for otherwise reporting simple errors, where None is returned on error
+- Optional struct fields
+- Struct fields that can be loaned or "taken"
+- Optional function arguments
+- Nullable pointers
+- Swapping things out of difficult situations
+
+## Further Information
+
+- [Option Enum Format](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-enum-definitions)
+- [Option Module Documentation](https://doc.rust-lang.org/std/option/)
+- [Option Enum Documentation](https://doc.rust-lang.org/std/option/enum.Option.html)
+- [if let](https://doc.rust-lang.org/rust-by-example/flow_control/if_let.html)
+- [while let](https://doc.rust-lang.org/rust-by-example/flow_control/while_let.html)

exercises/options/options1.rs

@@ -0,0 +1,39 @@
+// 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 :(
+fn maybe_icecream(time_of_day: u16) -> Option<u16> {
+    // We use the 24-hour system here, so 10PM is a value of 22 and 12AM is a
+    // value of 0 The Option output should gracefully handle cases where
+    // time_of_day > 23.
+    // TODO: Complete the function body - remember to return an Option!
+    ???
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn check_icecream() {
+        assert_eq!(maybe_icecream(9), Some(5));
+        assert_eq!(maybe_icecream(10), Some(5));
+        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, 5);
+    }
+}

exercises/options/options2.rs

@@ -0,0 +1,42 @@
+// options2.rs
+//
+// Execute `rustlings hint options2` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn simple_option() {
+        let target = "rustlings";
+        let optional_target = Some(target);
+
+        // TODO: Make this an if let statement whose value is "Some" type
+        word = optional_target {
+            assert_eq!(word, target);
+        }
+    }
+
+    #[test]
+    fn layered_option() {
+        let range = 10;
+        let mut optional_integers: Vec<Option<i8>> = vec![None];
+
+        for i in 1..(range + 1) {
+            optional_integers.push(Some(i));
+        }
+
+        let mut cursor = range;
+
+        // TODO: make this a while let statement - remember that vector.pop also
+        // adds another layer of Option<T>. You can stack `Option<T>`s into
+        // while let and if let.
+        integer = optional_integers.pop() {
+            assert_eq!(integer, cursor);
+            cursor -= 1;
+        }
+
+        assert_eq!(cursor, 0);
+    }
+}

exercises/options/options3.rs

@@ -0,0 +1,21 @@
+// options3.rs
+//
+// Execute `rustlings hint options3` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+struct Point {
+    x: i32,
+    y: i32,
+}
+
+fn main() {
+    let y: Option<Point> = Some(Point { x: 100, y: 200 });
+
+    match y {
+        Some(p) => println!("Co-ordinates are {},{} ", p.x, p.y),
+        _ => panic!("no match!"),
+    }
+    y; // Fix without deleting this line.
+}

exercises/primitive_types/README.md

@@ -1,9 +1,9 @@
-### Primitive Types
+# Primitive Types
 
 Rust has a couple of basic types that are directly implemented into the
 compiler. In this section, we'll go through the most important ones.
 
-#### Book Sections
+## Further information
 
 - [Data Types](https://doc.rust-lang.org/stable/book/ch03-02-data-types.html)
 - [The Slice Type](https://doc.rust-lang.org/stable/book/ch04-03-slices.html)