release: 4.0.0

Merge pull request #458 from Sowed/main
Merge pull request #1 from Sowed/then-to-than-docs-patch
2025-12-26 00:11:49 +02:00 · 2020-07-08 11:35:27 +02:00 · 2020-07-01 10:19:45 +02:00 · 2020-06-27 16:49:39 +04:00 · 2020-06-27 15:58:53 +04:00 · 2020-06-22 04:47:27 +02:00
106 changed files with 3355 additions and 2084 deletions
--- a/.all-contributorsrc
+++ b/.all-contributorsrc
@@ -0,0 +1,465 @@
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--- a/.editorconfig
+++ b/.editorconfig
@@ -0,0 +1,7 @@
+root = true
+
+[*.rs]
+end_of_line = lf
+insert_final_newfile = true
+indent_style = space
+indent_size = 4
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,7 @@
 target/
 **/*.rs.bk
 .DS_Store
+*.pdb
+exercises/clippy/Cargo.toml
+exercises/clippy/Cargo.lock
+.idea
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,11 +0,0 @@
-language: rust
-rust:
-  - stable
-  - beta
-  - nightly
-script: cargo test --verbose
-matrix:
-  allow_failures:
-    - rust: nightly
-  fast_finish: true
-cache: cargo
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,160 @@
+<a name="4.0.0"></a>
+## 4.0.0 (2020-07-08)
+
+#### Breaking Changes
+
+*   Add a --nocapture option to display test harnesses' outputs ([8ad5f9bf](https://github.com/rust-lang/rustlings/commit/8ad5f9bf531a4848b1104b7b389a20171624c82f)
+*   Rename test to quiz, fixes #244 ([010a0456](https://github.com/rust-lang/rustlings/commit/010a04569282149cea7f7a76fc4d7f4c9f0f08dd)
+
+#### Features
+
+*   Add traits README ([173bb141](https://github.com/rust-lang/rustlings/commit/173bb14140c5530cbdb59e53ace3991a99d804af))
+*   Add box1.rs exercise ([7479a473](https://github.com/rust-lang/rustlings/commit/7479a4737bdcac347322ad0883ca528c8675e720))
+*   Rewrite try_from_into (#393) ([763aa6e3](https://github.com/rust-lang/rustlings/commit/763aa6e378a586caae2d8d63755a85eeba227933))
+*   Add if2 exercise ([1da84b5f](https://github.com/rust-lang/rustlings/commit/1da84b5f7c489f65bd683c244f13c7d1ee812df0))
+*   Added exercise structs3.rs ([b66e2e09](https://github.com/rust-lang/rustlings/commit/b66e2e09622243e086a0f1258dd27e1a2d61c891))
+*   Add exercise variables6 covering const (#352) ([5999acd2](https://github.com/rust-lang/rustlings/commit/5999acd24a4f203292be36e0fd18d385887ec481))
+
+#### Bug Fixes
+
+*   Change then to than ([ddd98ad7](https://github.com/rust-lang/rustlings/commit/ddd98ad75d3668fbb10eff74374148aa5ed2344d))
+*   rename quiz1 to tests1 in info (#420) ([0dd1c6ca](https://github.com/rust-lang/rustlings/commit/0dd1c6ca6b389789e0972aa955fe17aa15c95f29))
+*   fix quiz naming inconsistency (#421) ([5563adbb](https://github.com/rust-lang/rustlings/commit/5563adbb890587fc48fbbc9c4028642687f1e85b))
+*   confine the user further in variable exercises ([06ef4cc6](https://github.com/rust-lang/rustlings/commit/06ef4cc654e75d22a526812919ee49b8956280bf))
+*   update iterator and macro text for typos and clarity ([95900828](https://github.com/rust-lang/rustlings/commit/959008284834bece0196a01e17ac69a7e3590116))
+*   update generics2       closes #362 ([964c974a](https://github.com/rust-lang/rustlings/commit/964c974a0274199d755073b917c2bc5da0c9b4f1))
+*   confusing comment in conversions/try_from_into.rs ([c9e4f2cf](https://github.com/rust-lang/rustlings/commit/c9e4f2cfb4c48d0b7451263cfb43b9426438122d))
+* **arc1:**  Passively introduce attributes (#429) ([113cdae2](https://github.com/rust-lang/rustlings/commit/113cdae2d4e4c55905e8056ad326ede7fd7de356))
+* **box1:**  fix comment typo (#426) ([bb2ca251](https://github.com/rust-lang/rustlings/commit/bb2ca251106b27a7272d9a30872904dd1376654c))
+* **errorsn:**  Try harder to confine the user. (#388) ([2b20c8a0](https://github.com/rust-lang/rustlings/commit/2b20c8a0f5774d07c58d110d75879f33fc6273b5))
+* **from_into.rs:**  typo ([a901499e](https://github.com/rust-lang/rustlings/commit/a901499ededd3ce1995164700514fe4e9a0373ea))
+* **generics2:**  Guide students to the answer (#430) ([e6bd8021](https://github.com/rust-lang/rustlings/commit/e6bd8021d9a7dd06feebc30c9d5f953901d7b419))
+* **installation:**
+  *  Provide a backup git reference when tag can't be curl ([9e4fb100](https://github.com/rust-lang/rustlings/commit/9e4fb1009f1c9e3433915c03e22c2af422e5c5fe))
+  *  Check if python is available while checking for git,rustc and cargo ([9cfb617d](https://github.com/rust-lang/rustlings/commit/9cfb617d5b0451b4b51644a1298965390cda9884))
+* **option1:**
+  *  Don't add only zeros to the numbers array ([cce6a442](https://github.com/rust-lang/rustlings/commit/cce6a4427718724a9096800754cd3abeca6a1580))
+  *  Add cast to usize, as it is confusing in the context of an exercise about Option ([f6cffc7e](https://github.com/rust-lang/rustlings/commit/f6cffc7e487b42f15a6f958e49704c93a8d4465b))
+* **option2:**  Add TODO to comments (#400) ([10967bce](https://github.com/rust-lang/rustlings/commit/10967bce57682812dc0891a9f9757da1a9d87404))
+* **options1:**  Add hint about Array Initialization (#389) ([9f75554f](https://github.com/rust-lang/rustlings/commit/9f75554f2a30295996f03f0160b98c0458305502))
+* **test2:**  name of type String and &str (#394) ([d6c0a688](https://github.com/rust-lang/rustlings/commit/d6c0a688e6a96f93ad60d540d4b326f342fc0d45))
+* **variables6:**  minor typo (#419) ([524e17df](https://github.com/rust-lang/rustlings/commit/524e17df10db95f7b90a0f75cc8997182a8a4094))
+
+<a name="3.0.0"></a>
+## 3.0.0 (2020-04-11)
+
+#### Breaking Changes
+
+* make "compile" exercises print output (#278) ([3b6d5c](https://github.com/fmoko/rustlings/commit/3b6d5c3aaa27a242a832799eb66e96897d26fde3))
+
+#### Bug Fixes
+
+* **primitive_types:** revert primitive_types4 (#296) ([b3a3351e](https://github.com/rust-lang/rustlings/commit/b3a3351e8e6a0bdee07077d7b0382953821649ae))
+* **run:**  compile clippy exercise files (#295) ([3ab084a4](https://github.com/rust-lang/rustlings/commit/3ab084a421c0f140ae83bf1fc3f47b39342e7373))
+* **conversions:**
+  * add additional test to meet exercise rules (#284) ([bc22ec3](https://github.com/fmoko/rustlings/commit/bc22ec382f843347333ef1301fc1bad773657f38))
+  * remove duplicate not done comment (#292) ([dab90f](https://github.com/fmoko/rustlings/commit/dab90f7b91a6000fe874e3d664f244048e5fa342))
+* don't hardcode documentation version for traits (#288) ([30e6af](https://github.com/fmoko/rustlings/commit/30e6af60690c326fb5d3a9b7335f35c69c09137d))
+
+#### Features
+
+*   add Option2 exercise (#290) ([86b5c08b](https://github.com/rust-lang/rustlings/commit/86b5c08b9bea1576127a7c5f599f5752072c087d))
+*   add excercise for option (#282) ([135e5d47](https://github.com/rust-lang/rustlings/commit/135e5d47a7c395aece6f6022117fb20c82f2d3d4))
+*   add new exercises for generics (#280) ([76be5e4e](https://github.com/rust-lang/rustlings/commit/76be5e4e991160f5fd9093f03ee2ba260e8f7229))
+* **ci:**  add buildkite config ([b049fa2c](https://github.com/rust-lang/rustlings/commit/b049fa2c84dba0f0c8906ac44e28fd45fba51a71))
+
+<a name="2.2.1"></a>
+### 2.2.1 (2020-02-27)
+
+#### Bug Fixes
+
+*   Re-add cloning the repo to install scripts ([3d9b03c5](https://github.com/rust-lang/rustlings/commit/3d9b03c52b8dc51b140757f6fd25ad87b5782ef5))
+
+#### Features
+
+*   Add clippy lints (#269) ([1e2fd9c9](https://github.com/rust-lang/rustlings/commit/1e2fd9c92f8cd6e389525ca1a999fca4c90b5921))
+
+<a name="2.2.0"></a>
+## 2.2.0 (2020-02-25)
+
+
+#### Bug Fixes
+
+*   Update deps to version compatable with aarch64-pc-windows (#263) ([19a93428](https://github.com/rust-lang/rustlings/commit/19a93428b3c73d994292671f829bdc8e5b7b3401))
+* **docs:**
+  * Added a necessary step to Windows installation process (#242) ([3906efcd](https://github.com/rust-lang/rustlings/commit/3906efcd52a004047b460ed548037093de3f523f))
+  * Fixed mangled sentence from book; edited for clarity (#266) ([ade52ff](https://github.com/rust-lang/rustlings/commit/ade52ffb739987287ddd5705944c8777705faed9)) 
+  * Updated iterators readme to account for iterators4 exercise (#273) ([bec8e3a](https://github.com/rust-lang/rustlings/commit/bec8e3a644cbd88db1c73ea5f1d8a364f4a34016))
+* **installation:**  make fatal errors more obvious (#272) ([17d0951e](https://github.com/rust-lang/rustlings/commit/17d0951e66fda8e11b204d5c4c41a0d5e22e78f7))
+* **iterators2:**
+  *  Remove reference to missing iterators2.rs (#245) ([419f7797](https://github.com/rust-lang/rustlings/commit/419f7797f294e4ce6a2b883199731b5bde77d262))
+* **as_ref_mut:** Enable a test and improve per clippy's suggestion (#256) ([dfdf809](https://github.com/rust-lang/rustlings/commit/dfdf8093ebbd4145864995627b812780de52f902))
+* **tests1:**
+  * Change test command ([fe10e06c](https://github.com/rust-lang/rustlings/commit/fe10e06c3733ddb4a21e90d09bf79bfe618e97ce) 
+  * Correct test command in tests1.rs comment (#263) ([39fa7ae](https://github.com/rust-lang/rustlings/commit/39fa7ae8b70ad468da49b06f11b2383135a63bcf))
+
+#### Features
+
+*   Add variables5.rs exercise (#264) ([0c73609e](https://github.com/rust-lang/rustlings/commit/0c73609e6f2311295e95d6f96f8c747cfc4cba03))
+*   Show a completion message when watching (#253) ([d25ee55a](https://github.com/rust-lang/rustlings/commit/d25ee55a3205882d35782e370af855051b39c58c))
+*   Add type conversion and parsing exercises (#249) ([0c85dc11](https://github.com/rust-lang/rustlings/commit/0c85dc1193978b5165491b99cc4922caf8d14a65))
+*   Created consistent money unit (#258) ([fd57f8f](https://github.com/rust-lang/rustlings/commit/fd57f8f2c1da2af8ddbebbccec214e6f40f4dbab))
+*   Enable test for exercise test4 (#276) ([8b971ff](https://github.com/rust-lang/rustlings/commit/8b971ffab6079a706ac925f5917f987932b55c07))
+*   Added traits exercises (#274 but specifically #216, which originally added
+    this :heart:) ([b559cdd](https://github.com/rust-lang/rustlings/commit/b559cdd73f32c0d0cfc1feda39f82b3e3583df17))
+
+
+<a name="2.1.0"></a>
+## 2.1.0 (2019-11-27)
+
+#### Bug Fixes
+
+* add line numbers in several exercises and hints ([b565c4d3](https://github.com/rust-lang/rustlings/commit/b565c4d3e74e8e110bef201a082fa1302722a7c3))
+* **arc1:**  Fix some words in the comment ([c42c3b21](https://github.com/rust-lang/rustlings/commit/c42c3b2101df9164c8cd7bb344def921e5ba3e61))
+* **enums:**  Add link to chapter on pattern syntax (#242) ([615ce327](https://github.com/rust-lang/rustlings/commit/615ce3279800c56d89f19d218ccb7ef576624feb))
+* **primitive_types4:**
+  *  update outdated hint ([4c5189df](https://github.com/rust-lang/rustlings/commit/4c5189df2bdd9a231f6b2611919ba5aa14da0d3f))
+  *  update outdated comment ([ded2c034](https://github.com/rust-lang/rustlings/commit/ded2c034ba93fa1e3c2c2ea16b83abc1a57265e8))
+* **strings2:**  update line number in hint ([a09f684f](https://github.com/rust-lang/rustlings/commit/a09f684f05c58d239a6fc59ec5f81c2533e8b820))
+* **variables1:**  Correct wrong word in comment ([fda5a470](https://github.com/rust-lang/rustlings/commit/fda5a47069e0954f16a04e8e50945e03becb71a5))
+
+#### Features
+
+* **watch:**  show hint while watching ([8143d57b](https://github.com/rust-lang/rustlings/commit/8143d57b4e88c51341dd4a18a14c536042cc009c))
+
+<a name="2.0.0"></a>
+## 2.0.0 (2019-11-12)
+
+#### Bug Fixes
+
+* **default:**  Clarify the installation procedure ([c371b853](https://github.com/rust-lang/rustlings/commit/c371b853afa08947ddeebec0edd074b171eeaae0))
+* **info:**  Fix trailing newlines for hints ([795b6e34](https://github.com/rust-lang/rustlings/commit/795b6e348094a898e9227a14f6232f7bb94c8d31))
+* **run:**  make `run` never prompt ([4b265465](https://github.com/rust-lang/rustlings/commit/4b26546589f7d2b50455429482cf1f386ceae8b3))
+
+#### Breaking Changes
+
+*   Refactor hint system ([9bdb0a12](https://github.com/rust-lang/rustlings/commit/9bdb0a12e45a8e9f9f6a4bd4a9c172c5376c7f60))
+*   improve `watch` execution mode ([2cdd6129](https://github.com/rust-lang/rustlings/commit/2cdd61294f0d9a53775ee24ad76435bec8a21e60))
+*   Index exercises by name ([627cdc07](https://github.com/rust-lang/rustlings/commit/627cdc07d07dfe6a740e885e0ddf6900e7ec336b))
+* **run:**  makes `run` never prompt ([4b265465](https://github.com/rust-lang/rustlings/commit/4b26546589f7d2b50455429482cf1f386ceae8b3))
+
+#### Features
+
+* **cli:**  check for rustc before doing anything ([36a033b8](https://github.com/rust-lang/rustlings/commit/36a033b87a6549c1e5639c908bf7381c84f4f425))
+* **hint:**  Add test for hint ([ce9fa6eb](https://github.com/rust-lang/rustlings/commit/ce9fa6ebbfdc3e7585d488d9409797285708316f))
+
+<a name="1.5.1"></a>
+### 1.5.1 (2019-11-11)
+
+#### Bug Fixes
+
+* **errors3:**  Update hint ([dcfb427b](https://github.com/rust-lang/rustlings/commit/dcfb427b09585f0193f0a294443fdf99f11c64cb), closes [#185](https://github.com/rust-lang/rustlings/issues/185))
+* **if1:**  Remove `return` reference ([ad03d180](https://github.com/rust-lang/rustlings/commit/ad03d180c9311c0093e56a3531eec1a9a70cdb45))
+* **strings:**  Move Strings before Structs ([6dcecb38](https://github.com/rust-lang/rustlings/commit/6dcecb38a4435593beb87c8e12d6314143631482), closes [#204](https://github.com/rust-lang/rustlings/issues/204))
+* **structs1:**  Remove misleading comment ([f72e5a8f](https://github.com/rust-lang/rustlings/commit/f72e5a8f05568dde04eaeac10b9a69872f21cb37))
+* **threads:**  Move Threads behind SLT ([fbe91a67](https://github.com/rust-lang/rustlings/commit/fbe91a67a482bfe64cbcdd58d06ba830a0f39da3), closes [#205](https://github.com/rust-lang/rustlings/issues/205))
+* **watch:** clear screen before each `verify()`  ([3aff590](https://github.com/rust-lang/rustlings/commit/3aff59085586c24196a547c2693adbdcf4432648))
+
 <a name="1.5.0"></a>
 ## 1.5.0 (2019-11-09)

--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -35,8 +35,11 @@ You want to make sure where in the file you add your exercise. If you're not sur
 ```diff
  ...
 + [[exercises]]
+ name = "yourTopicN"
 + path = "exercises/yourTopic/yourTopicN.rs"
 + mode = "compile"
+ hint = """
+ Some kind of useful hint for your exercise."""
  ...
 ```

@@ -125,4 +128,4 @@ BREAKING CHANGE: This has to be done because lorem ipsum dolor
 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!
+merge it in!
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,13 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "aho-corasick"
-version = "0.6.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "memchr 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "aho-corasick"
 version = "0.7.3"
@@ -21,7 +13,7 @@ name = "ansi_term"
 version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -42,7 +34,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
 "termion 1.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -74,17 +66,6 @@ dependencies = [
 "vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

-[[package]]
-name = "clicolors-control"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
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- "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "clicolors-control"
 version = "1.0.0"
@@ -93,7 +74,7 @@ dependencies = [
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 "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -106,23 +87,7 @@ dependencies = [

 [[package]]
 name = "console"
-version = "0.6.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "clicolors-control 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "termios 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "console"
-version = "0.7.5"
+version = "0.7.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
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@@ -134,7 +99,22 @@ dependencies = [
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 "termios 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "console"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "clicolors-control 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "encode_unicode 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "termios 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -168,6 +148,14 @@ dependencies = [
 "redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "float-cmp"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fsevent"
 version = "0.4.0"
@@ -204,20 +192,26 @@ name = "fuchsia-zircon-sys"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"

+[[package]]
+name = "glob"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "indicatif"
-version = "0.9.0"
+version = "0.10.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "console 0.7.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "lazy_static 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "console 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "number_prefix 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
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-version = "0.6.1"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
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@@ -256,11 +250,6 @@ dependencies = [
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-[[package]]
-name = "lazy_static"
-version = "0.2.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
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 version = "1.3.0"
@@ -343,25 +332,45 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

+[[package]]
+name = "normalize-line-endings"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
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-version = "4.0.12"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
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- "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "inotify 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
 "mio 0.6.19 (registry+https://github.com/rust-lang/crates.io-index)",
 "mio-extras 2.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
 "walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "number_prefix"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -391,7 +400,7 @@ dependencies = [
 "redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
 "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "smallvec 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -400,7 +409,10 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "float-cmp 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "normalize-line-endings 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "predicates-core 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -448,7 +460,7 @@ dependencies = [
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 "rand_pcg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_xorshift 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -496,7 +508,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -509,7 +521,7 @@ dependencies = [
 "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -550,18 +562,6 @@ dependencies = [
 "redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

-[[package]]
-name = "regex"
-version = "0.2.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "aho-corasick 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "memchr 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex-syntax 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "thread_local 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "utf8-ranges 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "regex"
 version = "1.1.6"
@@ -574,14 +574,6 @@ dependencies = [
 "utf8-ranges 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

-[[package]]
-name = "regex-syntax"
-version = "0.5.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "ucd-util 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "regex-syntax"
 version = "0.6.6"
@@ -600,13 +592,16 @@ dependencies = [

 [[package]]
 name = "rustlings"
-version = "1.4.1"
+version = "3.0.0"
 dependencies = [
 "assert_cmd 0.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "console 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "indicatif 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "notify 4.0.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "console 0.7.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "indicatif 0.10.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "notify 4.0.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "predicates 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "serde 1.0.92 (registry+https://github.com/rust-lang/crates.io-index)",
 "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -774,7 +769,7 @@ version = "2.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "same-file 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

@@ -785,7 +780,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"

 [[package]]
 name = "winapi"
-version = "0.3.7"
+version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -807,7 +802,7 @@ name = "winapi-util"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

 [[package]]
@@ -825,7 +820,6 @@ dependencies = [
 ]

 [metadata]
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 "checksum aho-corasick 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e6f484ae0c99fec2e858eb6134949117399f222608d84cadb3f58c1f97c2364c"
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@@ -834,27 +828,27 @@ dependencies = [
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 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
-"checksum lazy_static 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "76f033c7ad61445c5b347c7382dd1237847eb1bce590fe50365dcb33d546be73"
 "checksum lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bc5729f27f159ddd61f4df6228e827e86643d4d3e7c32183cb30a1c08f604a14"
 "checksum lazycell 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b294d6fa9ee409a054354afc4352b0b9ef7ca222c69b8812cbea9e7d2bf3783f"
 "checksum libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)" = "6281b86796ba5e4366000be6e9e18bf35580adf9e63fbe2294aadb587613a319"
@@ -865,7 +859,10 @@ dependencies = [
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 "checksum miow 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f2f3b1cf331de6896aabf6e9d55dca90356cc9960cca7eaaf408a355ae919"
 "checksum net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)" = "42550d9fb7b6684a6d404d9fa7250c2eb2646df731d1c06afc06dcee9e1bcf88"
-"checksum notify 4.0.12 (registry+https://github.com/rust-lang/crates.io-index)" = "3572d71f13ea8ed41867accd971fd564aa75934cf7a1fae03ddb8c74a8a49943"
+"checksum normalize-line-endings 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2e0a1a39eab95caf4f5556da9289b9e68f0aafac901b2ce80daaf020d3b733a8"
+"checksum notify 4.0.15 (registry+https://github.com/rust-lang/crates.io-index)" = "80ae4a7688d1fab81c5bf19c64fc8db920be8d519ce6336ed4e7efe024724dbd"
+"checksum num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "6ba9a427cfca2be13aa6f6403b0b7e7368fe982bfa16fccc450ce74c46cd9b32"
+"checksum number_prefix 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "dbf9993e59c894e3c08aa1c2712914e9e6bf1fcbfc6bef283e2183df345a4fee"
 "checksum numtoa 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b8f8bdf33df195859076e54ab11ee78a1b208382d3a26ec40d142ffc1ecc49ef"
 "checksum parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fa7767817701cce701d5585b9c4db3cdd02086398322c1d7e8bf5094a96a2ce7"
 "checksum parking_lot_core 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cb88cb1cb3790baa6776844f968fea3be44956cf184fa1be5a03341f5491278c"
@@ -887,9 +884,7 @@ dependencies = [
 "checksum rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
 "checksum redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)" = "12229c14a0f65c4f1cb046a3b52047cdd9da1f4b30f8a39c5063c8bae515e252"
 "checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
-"checksum regex 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9329abc99e39129fcceabd24cf5d85b4671ef7c29c50e972bc5afe32438ec384"
 "checksum regex 1.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "8f0a0bcab2fd7d1d7c54fa9eae6f43eddeb9ce2e7352f8518a814a4f65d60c58"
-"checksum regex-syntax 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7d707a4fa2637f2dca2ef9fd02225ec7661fe01a53623c1e6515b6916511f7a7"
 "checksum regex-syntax 0.6.6 (registry+https://github.com/rust-lang/crates.io-index)" = "dcfd8681eebe297b81d98498869d4aae052137651ad7b96822f09ceb690d0a96"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
 "checksum ryu 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "b96a9549dc8d48f2c283938303c4b5a77aa29bfbc5b54b084fb1630408899a8f"
@@ -917,7 +912,7 @@ dependencies = [
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-"checksum winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "f10e386af2b13e47c89e7236a7a14a086791a2b88ebad6df9bf42040195cf770"
+"checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
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 "checksum winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7168bab6e1daee33b4557efd0e95d5ca70a03706d39fa5f3fe7a236f584b03c9"
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,15 +1,16 @@
 [package]
 name = "rustlings"
-version = "1.5.0"
-authors = ["Marisa <mokou@posteo.de>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com"]
+version = "4.0.0"
+authors = ["Marisa <mokou@posteo.de>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
 edition = "2018"

 [dependencies]
 clap = "2.32.0"
-indicatif = "0.9.0"
-console = "0.6.2"
-notify = "4.0.0"
+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"]}

 [[bin]]
@@ -18,3 +19,5 @@ path = "src/main.rs"

 [dev-dependencies]
 assert_cmd = "0.11.0"
+predicates = "1.0.1"
+glob = "0.3.0"
--- a/README.md
+++ b/README.md
@@ -1,6 +1,9 @@
 ![crab pet](https://i.imgur.com/LbZJgmm.gif)
+<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
+[![All Contributors](https://img.shields.io/badge/all_contributors-48-orange.svg?style=flat-square)](#contributors-)
+<!-- ALL-CONTRIBUTORS-BADGE:END -->

-# rustlings 🦀❤️
+# rustlings 🦀❤️ [![Build status](https://badge.buildkite.com/7af93d81dc522c67a1ec8e33ff5705861b1cb36360b774807f.svg)](https://buildkite.com/mokou/rustlings)

 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!

@@ -15,8 +18,6 @@ Alternatively, for a first-time Rust learner, there's several other resources:

 _Note: If you're on MacOS, make sure you've installed Xcode and its developer tools by typing `xcode-select --install`._

-_Note: If you have Xcode 10+ installed, you also need to install the package file found at `/Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg`._
-
 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
@@ -33,10 +34,16 @@ This will install Rustlings and give you access to the `rustlings` command. Run

 ## Windows

-You can run:
+In PowerShell, set `ExecutionPolicy` to `RemoteSigned`:

 ```ps
-Invoke-WebRequest https://git.io/rustlings-win | Select-Object -ExpandProperty Content | Out-File $env:TMP/install_rustlings.ps1; Unblock-File $env:TMP/install_rustlings.ps1; Invoke-Expression $env:TMP/install_rustlings.ps1
+Set-ExecutionPolicy RemoteSigned
+```
+
+Then, you can run:
+
+```ps
+Start-BitsTransfer -Source https://git.io/rustlings-win -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.
@@ -48,7 +55,7 @@ Basically: Clone the repository, checkout to the latest tag, run `cargo install`
 ```bash
 git clone https://github.com/rust-lang/rustlings
 cd rustlings
-git checkout tags/1.5.0 # or whatever the latest version is (find out at https://github.com/rust-lang/rustlings/releases/latest)
+git checkout tags/4.0.0 # or whatever the latest version is (find out at https://github.com/rust-lang/rustlings/releases/latest)
 cargo install --force --path .
 ```

@@ -80,14 +87,19 @@ This will do the same as watch, but it'll quit after running.
 In case you want to go by your own order, or want to only verify a single exercise, you can run:

 ```bash
-rustlings run exercises/path/to/exercise.rs
+rustlings run myExercise1
 ```

-In case you get stuck, there is usually a hint at the bottom of each exercise.
+In case you get stuck, you can run the following command to get a hint for your
+exercise:
+
+``` bash
+rustlings hint myExercise1
+```

 ## Testing yourself

-After every couple of sections, there will be a test that'll test your knowledge on a bunch of sections at once. These tests are found in `exercises/testN.rs`.
+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`.

 ## Completion

@@ -111,7 +123,78 @@ If you are interested in improving or adding new ones, please feel free to contr

 See [CONTRIBUTING.md](./CONTRIBUTING.md).

-## Credits
+## Contributors ✨

-`rustlings` was originally written by [Carol](https://github.com/carols10cents)!
+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" width="100px;" alt=""/><br /><sub><b>Carol (Nichols &#124;&#124; Goulding)</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>QuietMisdreavus</b></sub></a><br /><a href="https://github.com/fmoko/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" 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" width="100px;" alt=""/><br /><sub><b>Hynek Schlawack</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Katharina Fey</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>lukabavdaz</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Erik Vesteraas</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>delet0r</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Shaun Bennett</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Andrew Bagshaw</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Kyle Isom</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Colin Pitrat</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Zac Anger</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Matthias Geier</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Chris Pearce</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Yvan Sraka</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Denys Smirnov</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>eddyp</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Brian Kung</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Russell</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Dan Wilhelm</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Jesse</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Fredrik Jambrén</b></sub></a><br /><a href="https://github.com/fmoko/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" 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" width="100px;" alt=""/><br /><sub><b>nkanderson</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Ajax M</b></sub></a><br /><a href="https://github.com/fmoko/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" 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" width="100px;" alt=""/><br /><sub><b>vyaslav</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>George</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Thomas Holloway</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Jubilee</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>WofWca</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Roberto Vidal</b></sub></a><br /><a href="https://github.com/fmoko/rustlings/commits?author=jrvidal" title="Code">💻</a> <a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Jens</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Rahat Ahmed</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Abdou Seck</b></sub></a><br /><a href="https://github.com/fmoko/rustlings/commits?author=AbdouSeck" title="Code">💻</a> <a href="#content-AbdouSeck" title="Content">🖋</a> <a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Katie</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Socrates</b></sub></a><br /><a href="https://github.com/fmoko/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" 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" width="100px;" alt=""/><br /><sub><b>Harrison Metzger</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Torben Jonas</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Paul Bissex</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Steven Mann</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Mario Reder</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>skim</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Sanjay K</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Rohan Jain</b></sub></a><br /><a href="https://github.com/fmoko/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" width="100px;" alt=""/><br /><sub><b>Said Aspen</b></sub></a><br /><a href="https://github.com/fmoko/rustlings/commits?author=saidaspen" title="Code">💻</a> <a href="#content-saidaspen" title="Content">🖋</a></td>
+  </tr>
+</table>
+
+<!-- markdownlint-enable -->
+<!-- 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!
--- a/buildkite.yml
+++ b/buildkite.yml
@@ -0,0 +1,5 @@
+steps:
+  - label: "Test with stable"
+    command: rustup run stable cargo test
+  - label: "Test with beta"
+    command: rustup run beta cargo test
--- a/default_out.txt
+++ b/default_out.txt
@@ -7,7 +7,8 @@ Let's make sure you're up to speed:
 - You have `~/.cargo/bin` added to your PATH variable
 - You have cloned this repository (https://github.com/rust-lang/rustlings)
 - You have installed Rust language support for your editor
- You have locally installed the `rustlings` command by running:
+- You have locally installed the `rustlings` command by running an
+  installation script or manually executing:

 cargo install --force --path .

@@ -15,4 +16,4 @@ If you've done all of this (or even most of it), congrats! You're ready
 to start working with Rust.

 To get started, run `rustlings watch` in order to get the first exercise.
-Make sure to have your editor open!
+Make sure to have your editor open!
--- a/exercises/clippy/README.md
+++ b/exercises/clippy/README.md
@@ -0,0 +1,8 @@
+### 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/).
--- a/exercises/clippy/clippy1.rs
+++ b/exercises/clippy/clippy1.rs
@@ -0,0 +1,17 @@
+// 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 :)
+
+// I AM NOT DONE
+
+fn main() {
+    let x = 1.2331f64;
+    let y = 1.2332f64;
+    if y != x {
+        println!("Success!");
+    }
+}
--- a/exercises/clippy/clippy2.rs
+++ b/exercises/clippy/clippy2.rs
@@ -0,0 +1,13 @@
+// clippy2.rs
+// Make me compile! Execute `rustlings hint clippy2` for hints :)
+
+// I AM NOT DONE
+
+fn main() {
+    let mut res = 42;
+    let option = Some(12);
+    for x in option {
+        res += x;
+    }
+    println!("{}", res);
+}
--- a/exercises/conversions/README.md
+++ b/exercises/conversions/README.md
@@ -0,0 +1,20 @@
+### Type conversions
+
+
+Rust offers a multitude of ways to convert a value of a given type into another type.
+
+The simplest form of type conversion is a type cast expression. It is denoted with the binary operator `as`. For instance, `println!("{}", 1 + 1.0);` would not compile, since `1` is an integer while `1.0` is a float. However, `println!("{}", 1 as f32 + 1.0)` should compile. The exercise [`using_as`](using_as.rs) tries to cover this.
+
+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)
+
+Furthermore, the `std::str` module offers a trait called [`FromStr`](https://doc.rust-lang.org/std/str/trait.FromStr.html) which helps with converting strings into target types via the `parse` method on strings. If properly implemented for a given type `Person`, then `let p: Person = "Mark,20".parse().unwrap()` should both compile and run without panicking.
+
+These should be the main ways ***within the standard library*** to convert data into your desired types.
+
+#### Book Sections
+
+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).
--- a/exercises/conversions/as_ref_mut.rs
+++ b/exercises/conversions/as_ref_mut.rs
@@ -0,0 +1,51 @@
+// 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.
+
+// I AM NOT DONE
+// Obtain the number of bytes (not characters) in the given argument
+// 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
+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));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn different_counts() {
+        let s = "Café au lait";
+        assert_ne!(char_counter(s), byte_counter(s));
+    }
+
+    #[test]
+    fn same_counts() {
+        let s = "Cafe au lait";
+        assert_eq!(char_counter(s), byte_counter(s));
+    }
+
+    #[test]
+    fn different_counts_using_string() {
+        let s = String::from("Café au lait");
+        assert_ne!(char_counter(s.clone()), byte_counter(s));
+    }
+
+    #[test]
+    fn same_counts_using_string() {
+        let s = String::from("Cafe au lait");
+        assert_eq!(char_counter(s.clone()), byte_counter(s));
+    }
+}
--- a/exercises/conversions/from_into.rs
+++ b/exercises/conversions/from_into.rs
@@ -0,0 +1,116 @@
+// 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
+#[derive(Debug)]
+struct Person {
+    name: String,
+    age: usize,
+}
+
+// We implement the Default trait to use it as a fallback
+// when the provided string is not convertible into a Person object
+impl Default for Person {
+    fn default() -> Person {
+        Person {
+            name: String::from("John"),
+            age: 30,
+        }
+    }
+}
+
+// I AM NOT DONE
+// 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
+impl From<&str> for Person {
+    fn from(s: &str) -> Person {
+    }
+}
+
+fn main() {
+    // Use the `from` function
+    let p1 = Person::from("Mark,20");
+    // Since From is implemented for Person, we should be able to use Into
+    let p2: Person = "Gerald,70".into();
+    println!("{:?}", p1);
+    println!("{:?}", p2);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_default() {
+        // Test that the default person is 30 year old John
+        let dp = Person::default();
+        assert_eq!(dp.name, "John");
+        assert_eq!(dp.age, 30);
+    }
+    #[test]
+    fn test_bad_convert() {
+        // Test that John is returned when bad string is provided
+        let p = Person::from("");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+    #[test]
+    fn test_good_convert() {
+        // Test that "Mark,20" works
+        let p = Person::from("Mark,20");
+        assert_eq!(p.name, "Mark");
+        assert_eq!(p.age, 20);
+    }
+    #[test]
+    fn test_bad_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);
+    }
+
+    #[test]
+    fn test_missing_comma_and_age() {
+        let p: Person = Person::from("Mark");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_age() {
+        let p: Person = Person::from("Mark,");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name() {
+        let p: Person = Person::from(",1");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name_and_age() {
+        let p: Person = Person::from(",");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+
+    #[test]
+    fn test_missing_name_and_invalid_age() {
+        let p: Person = Person::from(",one");
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 30);
+    }
+}
--- a/exercises/conversions/from_str.rs
+++ b/exercises/conversions/from_str.rs
@@ -0,0 +1,86 @@
+// 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::str::FromStr;
+
+#[derive(Debug)]
+struct Person {
+    name: String,
+    age: usize,
+}
+
+// I AM NOT DONE
+// Steps:
+// 1. If the length of the provided string is 0, then return an error
+// 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 an error
+// 5. Extract the other element from the split operation and parse it into a `usize` as the age
+//    with something like `"4".parse::<usize>()`.
+// If while parsing the age, something goes wrong, then return an error
+// Otherwise, then return a Result of a Person object
+impl FromStr for Person {
+    type Err = String;
+    fn from_str(s: &str) -> Result<Person, Self::Err> {
+    }
+}
+
+fn main() {
+    let p = "Mark,20".parse::<Person>().unwrap();
+    println!("{:?}", p);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn empty_input() {
+        assert!("".parse::<Person>().is_err());
+    }
+    #[test]
+    fn good_input() {
+        let p = "John,32".parse::<Person>();
+        assert!(p.is_ok());
+        let p = p.unwrap();
+        assert_eq!(p.name, "John");
+        assert_eq!(p.age, 32);
+    }
+    #[test]
+    #[should_panic]
+    fn missing_age() {
+        "John,".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn invalid_age() {
+        "John,twenty".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_comma_and_age() {
+        "John".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_name() {
+        ",1".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_name_and_age() {
+        ",".parse::<Person>().unwrap();
+    }
+
+    #[test]
+    #[should_panic]
+    fn missing_name_and_invalid_age() {
+        ",one".parse::<Person>().unwrap();
+    }
+
+}
--- a/exercises/conversions/try_from_into.rs
+++ b/exercises/conversions/try_from_into.rs
@@ -0,0 +1,130 @@
+// 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
+use std::convert::{TryInto, TryFrom};
+
+#[derive(Debug)]
+struct Color {
+    red: u8,
+    green: u8,
+    blue: u8,
+}
+
+// I AM NOT DONE
+
+// Your task is to complete this implementation
+// and return an Ok result of inner type Color.
+// You need create implementation for a tuple of three integer,
+// an array of three integer and slice of integer.
+//
+// Note, that implementation for tuple and array will be checked at compile-time,
+// but slice implementation need check slice length!
+// Also note, that chunk of correct rgb color must be integer in range 0..=255.
+
+// Tuple implementation
+impl TryFrom<(i16, i16, i16)> for Color {
+    type Error = String;
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+    }
+}
+
+// Array implementation
+impl TryFrom<[i16; 3]> for Color {
+    type Error = String;
+    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+    }
+}
+
+// Slice implementation
+impl TryFrom<&[i16]> for Color {
+    type Error = String;
+    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+    }
+}
+
+fn main() {
+    // Use the `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
+    let c2: Result<Color, _> = [183, 65, 14].try_into();
+    println!("{:?}", c2);
+
+    let v = vec![183, 65, 14];
+    // With slice we should use `from` function
+    let c3 = Color::try_from(&v[..]);
+    println!("{:?}", c3);
+    // or take slice within round brackets and use Into
+    let c4: Result<Color, _> = (&v[..]).try_into();
+    println!("{:?}", c4);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[should_panic]
+    fn test_tuple_out_of_range_positive() {
+        let _ = Color::try_from((256, 1000, 10000)).unwrap();
+    }
+    #[test]
+    #[should_panic]
+    fn test_tuple_out_of_range_negative() {
+        let _ = Color::try_from((-1, -10, -256)).unwrap();
+    }
+    #[test]
+    fn test_tuple_correct() {
+        let c: Color = (183, 65, 14).try_into().unwrap();
+        assert_eq!(c.red, 183);
+        assert_eq!(c.green, 65);
+        assert_eq!(c.blue, 14);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_array_out_of_range_positive() {
+        let _: Color = [1000, 10000, 256].try_into().unwrap();
+    }
+    #[test]
+    #[should_panic]
+    fn test_array_out_of_range_negative() {
+        let _: Color = [-10, -256, -1].try_into().unwrap();
+    }
+    #[test]
+    fn test_array_correct() {
+        let c: Color = [183, 65, 14].try_into().unwrap();
+        assert_eq!(c.red, 183);
+        assert_eq!(c.green, 65);
+        assert_eq!(c.blue, 14);
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_slice_out_of_range_positive() {
+        let arr = [10000, 256, 1000];
+        let _ = Color::try_from(&arr[..]).unwrap();
+    }
+    #[test]
+    #[should_panic]
+    fn test_slice_out_of_range_negative() {
+        let arr = [-256, -1, -10];
+        let _ = Color::try_from(&arr[..]).unwrap();
+    }
+    #[test]
+    fn test_slice_correct() {
+        let v = vec![183, 65, 14];
+        let c = Color::try_from(&v[..]).unwrap();
+        assert_eq!(c.red, 183);
+        assert_eq!(c.green, 65);
+        assert_eq!(c.blue, 14);
+    }
+    #[test]
+    #[should_panic]
+    fn test_slice_excess_length() {
+        let v = vec![0, 0, 0, 0];
+        let _ = Color::try_from(&v[..]).unwrap();
+    }
+}
--- a/exercises/conversions/using_as.rs
+++ b/exercises/conversions/using_as.rs
@@ -0,0 +1,17 @@
+// 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.
+
+// I AM NOT DONE
+// The goal is to make sure that the division does not fail to compile
+fn average(values: &[f64]) -> f64 {
+    let total = values
+        .iter()
+        .fold(0.0, |a, b| a + b);
+    total / values.len()
+}
+
+fn main() {
+    let values = [3.5, 0.3, 13.0, 11.7];
+    println!("{}", average(&values));
+}
--- a/exercises/enums/README.md
+++ b/exercises/enums/README.md
@@ -1,7 +1,10 @@
 ### Enums

-Rust allows you to define a type called `enums` which allow you to enumerate possible values. In combination with enums, we have the concept of `pattern matching` in Rust, which makes it easy to run different code for different values of an enumeration. Enums, while available in many languages, Rust's enums are most similar to `algebraic data types` in functional languages, such as F#, OCaml, and Haskell.
+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

 - [Enums](https://doc.rust-lang.org/book/ch06-00-enums.html)
+- [Pattern syntax](https://doc.rust-lang.org/book/ch18-03-pattern-syntax.html)
--- a/exercises/enums/enums1.rs
+++ b/exercises/enums/enums1.rs
@@ -1,5 +1,7 @@
 // enums1.rs
-// Make me compile! Scroll down for hints!
+// Make me compile! Execute `rustlings hint enums1` for hints!
+
+// I AM NOT DONE

 #[derive(Debug)]
 enum Message {
@@ -12,31 +14,3 @@ fn main() {
    println!("{:?}", Message::Move);
    println!("{:?}", Message::ChangeColor);
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// Hint: The declaration of the enumeration type has not been defined yet.
--- a/exercises/enums/enums2.rs
+++ b/exercises/enums/enums2.rs
@@ -1,5 +1,7 @@
 // enums2.rs
-// Make me compile! Scroll down for hints
+// Make me compile! Execute `rustlings hint enums2` for hints!
+
+// I AM NOT DONE

 #[derive(Debug)]
 enum Message {
@@ -24,38 +26,3 @@ fn main() {
        message.call();
    }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// Hint: you can create enumerations that have different variants with different types
-// such as no data, anonymous structs, a single string, tuples, ...etc
--- a/exercises/enums/enums3.rs
+++ b/exercises/enums/enums3.rs
@@ -1,6 +1,8 @@
 // enums3.rs
 // Address all the TODOs to make the tests pass!

+// I AM NOT DONE
+
 enum Message {
    // TODO: implement the message variant types based on their usage below
 }
@@ -51,7 +53,7 @@ mod tests {
        };
        state.process(Message::ChangeColor(255, 0, 255));
        state.process(Message::Echo(String::from("hello world")));
-        state.process(Message::Move{ x: 10, y: 15 });
+        state.process(Message::Move(Point{ x: 10, y: 15 }));
        state.process(Message::Quit);

        assert_eq!(state.color, (255, 0, 255));
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -4,7 +4,9 @@
 // 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.
-// Scroll down for hints!!!
+// Execute `rustlings hint errors1` for hints!
+
+// I AM NOT DONE

 pub fn generate_nametag_text(name: String) -> Option<String> {
    if name.len() > 0 {
@@ -38,36 +40,3 @@ mod tests {
        );
    }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// `Err` is one of the variants of `Result`, so what the 2nd test is saying
-// is that `generate_nametag_text` should return a `Result` instead of an
-// `Option`.
-
-// To make this change, you'll need to:
-// - update the return type in the function signature to be a Result<String, String> that
-//   could be the variants `Ok(String)` and `Err(String)`
-// - change the body of the function to return `Ok(stuff)` where it currently
-//   returns `Some(stuff)`
-// - change the body of the function to return `Err(error message)` where it
-//   currently returns `None`
-// - change the first test to expect `Ok(stuff)` where it currently expects
-//   `Some(stuff)`.
--- a/exercises/error_handling/errors2.rs
+++ b/exercises/error_handling/errors2.rs
@@ -14,7 +14,9 @@
 // and add.

 // There are at least two ways to implement this that are both correct-- but
-// one is a lot shorter! Scroll down for hints to both ways.
+// one is a lot shorter! Execute `rustlings hint errors2` for hints to both ways.
+
+// I AM NOT DONE

 use std::num::ParseIntError;

@@ -43,27 +45,3 @@ mod tests {
        );
    }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// One way to handle this is using a `match` statement on
-// `item_quantity.parse::<i32>()` where the cases are `Ok(something)` and
-// `Err(something)`. This pattern is very common in Rust, though, so there's
-// a `?` operator that does pretty much what you would make that match statement
-// do for you! Take a look at this section of the Error Handling chapter:
-// https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
-// and give it a try!
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -1,8 +1,10 @@
 // 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--
-// we can't use the `?` operator in the `main()` function! Why not?
-// What should we do instead? Scroll for hints!
+// `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!
+
+// I AM NOT DONE

 use std::num::ParseIntError;

@@ -27,36 +29,3 @@ pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {

    Ok(qty * cost_per_item + processing_fee)
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// Since the `?` operator returns an `Err` early if the thing it's trying to
-// do fails, you can only use the `?` operator in functions that have a
-// `Result` as their return type.
-
-// Hence the error that you get if you run this code is:
-
-// ```
-// error[E0277]: the `?` operator can only be used in a function that returns `Result` (or another type that implements `std::ops::Try`)
-// ```
-
-// So we have to use another way of handling a `Result` within `main`.
-
-// Decide what we should do if `pretend_user_input` has a string value that does
-// not parse to an integer, and implement that instead of using the `?`
-// operator.
--- a/exercises/error_handling/errorsn.rs
+++ b/exercises/error_handling/errorsn.rs
@@ -2,8 +2,10 @@
 // This is a bigger error exercise than the previous ones!
 // You can do it! :)
 //
-// Edit the `read_and_validate` function so that it compiles and
-// passes the tests... so many things could go wrong!
+// 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
@@ -13,7 +15,9 @@
 // type goes where the question marks are, and how do we return
 // that type from the body of read_and_validate?
 //
-// Scroll down for hints :)
+// Execute `rustlings hint errorsn` for hints :)
+
+// I AM NOT DONE

 use std::error;
 use std::fmt;
@@ -28,6 +32,10 @@ fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger,
    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());
@@ -98,150 +106,12 @@ enum CreationError {

 impl fmt::Display for CreationError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str((self as &dyn error::Error).description())
+        let description = match *self {
+            CreationError::Negative => "Number is negative",
+            CreationError::Zero => "Number is zero",
+        };
+        f.write_str(description)
    }
 }

-impl error::Error for CreationError {
-    fn description(&self) -> &str {
-        match *self {
-            CreationError::Negative => "Negative",
-            CreationError::Zero => "Zero",
-        }
-    }
-}
-
-
-
-
-
-
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-
-
-
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-
-
-
-
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-
-
-
-
-
-
-
-// First hint: To figure out what type should go where the ??? is, take a look
-// at the test helper function `test_with_str`, since it returns whatever
-// `read_and_validate` returns and`test_with_str` has its signature fully
-// specified.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// Next hint: There are three places in `read_and_validate` that we call a
-// function that returns a `Result` (that is, the functions might fail).
-// Apply the `?` operator on those calls so that we return immediately from
-// `read_and_validate` if those function calls fail.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// Another hint: under the hood, the `?` operator calls `From::from`
-// on the error value to convert it to a boxed trait object, a Box<dyn error::Error>,
-// which is polymorphic-- that means that lots of different kinds of errors
-// can be returned from the same function because all errors act the same
-// since they all implement the `error::Error` trait.
-// Check out this section of the book:
-// https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// Another another hint: Note that because the `?` operator returns
-// the *unwrapped* value in the `Ok` case, if we want to return a `Result` from
-// `read_and_validate` for *its* success case, we'll have to rewrap a value
-// that we got from the return value of a `?`ed call in an `Ok`-- this will
-// look like `Ok(something)`.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// Another another another hint: `Result`s must be "used", that is, you'll
-// get a warning if you don't handle a `Result` that you get in your
-// function. Read more about that in the `std::result` module docs:
-// https://doc.rust-lang.org/std/result/#results-must-be-used
+impl error::Error for CreationError {}
--- a/exercises/error_handling/option1.rs
+++ b/exercises/error_handling/option1.rs
@@ -1,57 +0,0 @@
-// option1.rs
-// This example panics because the second time it calls `pop`, the `vec`
-// is empty, so `pop` returns `None`, and `unwrap` panics if it's called
-// on `None`. Handle this in a more graceful way than calling `unwrap`!
-// Scroll down for hints :)
-
-pub fn pop_too_much() -> bool {
-    let mut list = vec![3];
-
-    let last = list.pop().unwrap();
-    println!("The last item in the list is {:?}", last);
-
-    let second_to_last = list.pop().unwrap();
-    println!(
-        "The second-to-last item in the list is {:?}",
-        second_to_last
-    );
-    true
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn should_not_panic() {
-        assert!(pop_too_much());
-    }
-}
-
-
-
-
-
-
-
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-
-
-// Try using a `match` statement where the arms are `Some(thing)` and `None`.
-// Or set a default value to print out if you get `None` by using the
-// function `unwrap_or`.
-// Or use an `if let` statement on the result of `pop()` to both destructure
-// a `Some` value and only print out something if we have a value!
--- a/exercises/error_handling/result1.rs
+++ b/exercises/error_handling/result1.rs
@@ -1,5 +1,7 @@
 // result1.rs
-// Make this test pass! Scroll down for hints :)
+// Make this test pass! Execute `rustlings hint result1` for hints :)
+
+// I AM NOT DONE

 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
@@ -25,22 +27,3 @@ fn test_creation() {
    );
    assert_eq!(Err(CreationError::Zero), PositiveNonzeroInteger::new(0));
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// `PositiveNonzeroInteger::new` is always creating a new instance and returning an `Ok` result.
-// It should be doing some checking, returning an `Err` result if those checks fail, and only
-// returning an `Ok` result if those checks determine that everything is... okay :)
--- a/exercises/functions/functions1.rs
+++ b/exercises/functions/functions1.rs
@@ -1,44 +1,8 @@
 // functions1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions1` for hints :)
+
+// I AM NOT DONE

 fn main() {
    call_me();
 }
-
-
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-
-
-// This main function is calling a function that it expects to exist, but the
-// function doesn't exist. It expects this function to have the name `call_me`.
-// It expects this function to not take any arguments and not return a value.
-// Sounds a lot like `main`, doesn't it?
--- a/exercises/functions/functions2.rs
+++ b/exercises/functions/functions2.rs
@@ -1,5 +1,7 @@
 // functions2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions2` for hints :)
+
+// I AM NOT DONE

 fn main() {
    call_me(3);
@@ -10,33 +12,3 @@ fn call_me(num) {
        println!("Ring! Call number {}", i + 1);
    }
 }
-
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-
-
-
-
-// Rust requires that all parts of a function's signature have type annotations,
-// but `call_me` is missing the type annotation of `num`.
--- a/exercises/functions/functions3.rs
+++ b/exercises/functions/functions3.rs
@@ -1,5 +1,7 @@
 // functions3.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions3` for hints :)
+
+// I AM NOT DONE

 fn main() {
    call_me();
@@ -10,33 +12,3 @@ fn call_me(num: i32) {
        println!("Ring! Call number {}", i + 1);
    }
 }
-
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-
-// This time, the function *declaration* is okay, but there's something wrong
-// with the place where we're calling the function.
--- a/exercises/functions/functions4.rs
+++ b/exercises/functions/functions4.rs
@@ -1,8 +1,10 @@
 // functions4.rs
-// Make me compile! Scroll down for hints :)
+// 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 (money unit) off, but if it's an odd number, it's 3 (money unit) less.
+// 10 Rustbucks off, but if it's an odd number, it's 3 Rustbucks off.
+
+// I AM NOT DONE

 fn main() {
    let original_price = 51;
@@ -20,25 +22,3 @@ fn sale_price(price: i32) -> {
 fn is_even(num: i32) -> bool {
    num % 2 == 0
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// The error message points to line 12 and says it expects a type after the
-// `->`. This is where the function's return type should be-- take a look at
-// the `is_even` function for an example!
--- a/exercises/functions/functions5.rs
+++ b/exercises/functions/functions5.rs
@@ -1,5 +1,7 @@
 // functions5.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint functions5` for hints :)
+
+// I AM NOT DONE

 fn main() {
    let answer = square(3);
@@ -9,39 +11,3 @@ fn main() {
 fn square(num: i32) -> i32 {
    num * num;
 }
-
-
-
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-
-
-
-
-
-
-
-
-
-
-// This is a really common error that can be fixed by removing one character.
-// It happens because Rust distinguishes between expressions and statements: expressions return
-// a value based on its operand, and statements simply return a () type which behaves just like `void` in C/C++ language.
-// We want to return a value of `i32` type from the `square` function, but it is returning a `()` type...
-// They are not the same. There are two solutions:
-// 1. Add a `return` ahead of `num * num;`
-// 2. remove `;`, make it to be `num * num`
--- a/exercises/generics/README.md
+++ b/exercises/generics/README.md
@@ -0,0 +1,7 @@
+### Generics
+
+In this section you'll learn about saving yourself many lines of code with generics!
+
+### Book Sections
+
+- [Generic Data Types](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html)
--- a/exercises/generics/generics1.rs
+++ b/exercises/generics/generics1.rs
@@ -0,0 +1,10 @@
+// This shopping list program isn't compiling! 
+// Use your knowledge of generics to fix it.
+
+// I AM NOT DONE
+
+fn main() {
+    let mut shopping_list: Vec<?> = Vec::new();
+    shopping_list.push("milk");
+}
+
--- a/exercises/generics/generics2.rs
+++ b/exercises/generics/generics2.rs
@@ -0,0 +1,28 @@
+// This powerful wrapper provides the ability to store a positive integer value.
+// Rewrite it using generics so that it supports wrapping ANY type.
+
+// I AM NOT DONE
+struct Wrapper {
+    value: u32
+}
+
+impl Wrapper {
+    pub fn new(value: u32) -> Self {
+        Wrapper { value }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn store_u32_in_wrapper() {
+        assert_eq!(Wrapper::new(42).value,  42);
+    }
+
+    #[test]
+    fn store_str_in_wrapper() {
+        assert_eq!(Wrapper::new("Foo").value, "Foo");
+    }
+}
--- a/exercises/generics/generics3.rs
+++ b/exercises/generics/generics3.rs
@@ -0,0 +1,48 @@
+// 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 to support alphabetical report cards, thereby making 
+// the second test pass.
+
+// 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+");
+    }
+}
--- a/exercises/if/if1.rs
+++ b/exercises/if/if1.rs
@@ -1,12 +1,13 @@
 // if1.rs

+// I AM NOT DONE
+
 pub fn bigger(a: i32, b: i32) -> i32 {
    // Complete this function to return the bigger number!
    // Do not use:
-    // - return
    // - another function call
    // - additional variables
-    // Scroll down for hints.
+    // Execute `rustlings hint if1` for hints
 }

 // Don't mind this for now :)
@@ -24,36 +25,3 @@ mod tests {
        assert_eq!(42, bigger(32, 42));
    }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// It's possible to do this in one line if you would like!
-// Some similar examples from other languages:
-// - In C(++) this would be: `a > b ? a : b`
-// - In Python this would be:  `a if a > b else b`
-// Remember in Rust that:
-// - the `if` condition does not need to be surrounded by parentheses
-// - `if`/`else` conditionals are expressions
-// - Each condition is followed by a `{}` block.
--- a/exercises/if/if2.rs
+++ b/exercises/if/if2.rs
@@ -0,0 +1,36 @@
+// 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 :)
+
+// I AM NOT DONE
+
+pub fn fizz_if_foo(fizzish: &str) -> &str {
+    if fizzish == "fizz" {
+        "foo"
+    } else {
+        1
+    }
+}
+
+// No test changes needed!
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn foo_for_fizz() {
+        assert_eq!(fizz_if_foo("fizz"), "foo")
+    }
+
+    #[test]
+    fn bar_for_fuzz() {
+        assert_eq!(fizz_if_foo("fuzz"), "bar")
+    }
+
+    #[test]
+    fn default_to_baz() {
+        assert_eq!(fizz_if_foo("literally anything"), "baz")
+    }
+}
--- a/exercises/macros/README.md
+++ b/exercises/macros/README.md
@@ -2,7 +2,7 @@

 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
-modules, instead we'll show you how to use and create them.
+macros. Instead, we'll show you how to use and create them.

 #### Book Sections

--- a/exercises/macros/macros1.rs
+++ b/exercises/macros/macros1.rs
@@ -1,5 +1,7 @@
 // macros1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint macros1` for hints :)
+
+// I AM NOT DONE

 macro_rules! my_macro {
    () => {
@@ -10,55 +12,3 @@ macro_rules! my_macro {
 fn main() {
    my_macro();
 }
-
-
-
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-
-
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-
-
-// When you call a macro, you need to add something special compared to a
-// regular function call. If you're stuck, take a look at what's inside
-// `my_macro`.
--- a/exercises/macros/macros2.rs
+++ b/exercises/macros/macros2.rs
@@ -1,5 +1,7 @@
 // macros2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint macros2` for hints :)
+
+// I AM NOT DONE

 fn main() {
    my_macro!();
@@ -10,64 +12,3 @@ macro_rules! my_macro {
        println!("Check out my macro!");
    };
 }
-
-
-
-
-
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-
-
-
-
-
-// Macros don't quite play by the same rules as the rest of Rust, in terms of
-// what's available where.
-
-
-
-
-
-
-
-
-// Unlike other things in Rust, the order of "where you define a macro" versus
-// "where you use it" actually matters.
--- a/exercises/macros/macros3.rs
+++ b/exercises/macros/macros3.rs
@@ -1,5 +1,8 @@
 // macros3.rs
-// Make me compile, without taking the macro out of the module! Scroll down for hints :)
+// Make me compile, without taking the macro out of the module!
+// Execute `rustlings hint macros3` for hints :)
+
+// I AM NOT DONE

 mod macros {
    macro_rules! my_macro {
@@ -12,64 +15,3 @@ mod macros {
 fn main() {
    my_macro!();
 }
-
-
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-
-// In order to use a macro outside of its module, you need to do something
-// special to the module to lift the macro out into its parent.
-
-
-
-
-
-
-
-
-// The same trick also works on "extern crate" statements for crates that have
-// exported macros, if you've seen any of those around.
--- a/exercises/macros/macros4.rs
+++ b/exercises/macros/macros4.rs
@@ -1,5 +1,7 @@
 // macros4.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint macros4` for hints :)
+
+// I AM NOT DONE

 macro_rules! my_macro {
    () => {
@@ -14,64 +16,3 @@ fn main() {
    my_macro!();
    my_macro!(7777);
 }
-
-
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-// You only need to add a single character to make this compile.
-
-
-
-
-
-
-
-
-
-// The way macros are written, it wants to see something between each
-// "macro arm", so it can separate them.
--- a/exercises/modules/modules1.rs
+++ b/exercises/modules/modules1.rs
@@ -1,5 +1,7 @@
 // modules1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint modules1` for hints :)
+
+// I AM NOT DONE

 mod sausage_factory {
    fn make_sausage() {
@@ -10,34 +12,3 @@ mod sausage_factory {
 fn main() {
    sausage_factory::make_sausage();
 }
-
-
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-// Everything is private in Rust by default-- but there's a keyword we can use
-// to make something public! The compiler error should point to the thing that
-// needs to be public.
--- a/exercises/modules/modules2.rs
+++ b/exercises/modules/modules2.rs
@@ -1,5 +1,7 @@
 // modules2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint modules2` for hints :)
+
+// I AM NOT DONE

 mod delicious_snacks {
    use self::fruits::PEAR as fruit;
@@ -23,25 +25,3 @@ fn main() {
        delicious_snacks::veggie
    );
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// The delicious_snacks module is trying to present an external
-// interface (the `fruit` and `veggie` constants) that is different than
-// its internal structure (the `fruits` and `veggies` modules and
-// associated constants). It's almost there except for one keyword missing for
-// each constant.
--- a/exercises/move_semantics/move_semantics1.rs
+++ b/exercises/move_semantics/move_semantics1.rs
@@ -1,5 +1,7 @@
 // move_semantics1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute `rustlings hint move_semantics1` for hints :)
+
+// I AM NOT DONE

 fn main() {
    let vec0 = Vec::new();
@@ -22,21 +24,3 @@ fn fill_vec(vec: Vec<i32>) -> Vec<i32> {

    vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// So you've got the "cannot borrow immutable local variable `vec1` as mutable" error on line 11,
-// right? The fix for this is going to be adding one keyword, and the addition is NOT on line 11
-// where the error is.
--- a/exercises/move_semantics/move_semantics2.rs
+++ b/exercises/move_semantics/move_semantics2.rs
@@ -1,5 +1,8 @@
 // move_semantics2.rs
-// Make me compile without changing line 10! Scroll down for hints :)
+// Make me compile without changing line 13!
+// Execute `rustlings hint move_semantics2` for hints :)
+
+// I AM NOT DONE

 fn main() {
    let vec0 = Vec::new();
@@ -23,31 +26,3 @@ fn fill_vec(vec: Vec<i32>) -> Vec<i32> {

    vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// So `vec0` is being *moved* into the function `fill_vec` when we call it on
-// line 7, which means it gets dropped at the end of `fill_vec`, which means we
-// can't use `vec0` again on line 10 (or anywhere else in `main` after the
-// `fill_vec` call for that matter). We could fix this in a few ways, try them
-// all!
-// 1. Make another, separate version of the data that's in `vec0` and pass that
-// to `fill_vec` instead.
-// 2. Make `fill_vec` borrow its argument instead of taking ownership of it,
-// and then copy the data within the function in order to return an owned
-// `Vec<i32>`
-// 3. Make `fill_vec` *mutably* borrow its argument (which will need to be
-// mutable), modify it directly, then not return anything. Then you can get rid
-// of `vec1` entirely -- note that this will change what gets printed by the
-// first `println!`
--- a/exercises/move_semantics/move_semantics3.rs
+++ b/exercises/move_semantics/move_semantics3.rs
@@ -1,7 +1,9 @@
 // move_semantics3.rs
 // Make me compile without adding new lines-- just changing existing lines!
 // (no lines with multiple semicolons necessary!)
-// Scroll down for hints :)
+// Execute `rustlings hint move_semantics3` for hints :)
+
+// I AM NOT DONE

 fn main() {
    let vec0 = Vec::new();
@@ -22,24 +24,3 @@ fn fill_vec(vec: Vec<i32>) -> Vec<i32> {

    vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// The difference between this one and the previous ones is that the first line
-// of `fn fill_vec` that had `let mut vec = vec;` is no longer there. You can,
-// instead of adding that line back, add `mut` in one place that will change
-// an existing binding to be a mutable binding instead of an immutable one :)
--- a/exercises/move_semantics/move_semantics4.rs
+++ b/exercises/move_semantics/move_semantics4.rs
@@ -1,7 +1,10 @@
 // move_semantics4.rs
 // Refactor this code so that instead of having `vec0` and creating the vector
 // in `fn main`, we instead create it within `fn fill_vec` and transfer the
-// freshly created vector from fill_vec to its caller. Scroll for hints!
+// freshly created vector from fill_vec to its caller.
+// Execute `rustlings hint move_semantics4` for hints!
+
+// I AM NOT DONE

 fn main() {
    let vec0 = Vec::new();
@@ -25,24 +28,3 @@ fn fill_vec() -> Vec<i32> {

    vec
 }
-
-
-
-
-
-
-
-
-
-
-
-
-// Stop reading whenever you feel like you have enough direction :) Or try
-// doing one step and then fixing the compiler errors that result!
-// So the end goal is to:
-// - get rid of the first line in main that creates the new vector
-// - so then `vec0` doesn't exist, so we can't pass it to `fill_vec`
-// - we don't want to pass anything to `fill_vec`, so its signature should
-//   reflect that it does not take any arguments
-// - since we're not creating a new vec in `main` anymore, we need to create
-//   a new vec in `fill_vec`, similarly to the way we did in `main`
--- a/exercises/option/README.md
+++ b/exercises/option/README.md
@@ -0,0 +1,9 @@
+### 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)
--- a/exercises/option/option1.rs
+++ b/exercises/option/option1.rs
@@ -0,0 +1,23 @@
+// 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;
+    }
+}
--- a/exercises/option/option2.rs
+++ b/exercises/option/option2.rs
@@ -0,0 +1,25 @@
+// option2.rs
+// Make me compile! Execute `rustlings hint option2` for hints
+
+// I AM NOT DONE
+
+fn main() {
+    let optional_value = Some(String::from("rustlings"));
+    // TODO: Make this an if let statement whose value is "Some" type
+    value = optional_value {
+        println!("the value of optional value is: {}", value);
+    } else {
+        println!("The optional value doesn't contain anything!");
+    }
+
+    let mut optional_values_vec: Vec<Option<i8>> = Vec::new();
+    for x in 1..10 {
+        optional_values_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
+    value = optional_values_vec.pop() {
+        println!("current value: {}", value);
+    }
+}
--- a/exercises/primitive_types/primitive_types1.rs
+++ b/exercises/primitive_types/primitive_types1.rs
@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)

+// I AM NOT DONE
+
 fn main() {
    // Booleans (`bool`)

--- a/exercises/primitive_types/primitive_types2.rs
+++ b/exercises/primitive_types/primitive_types2.rs
@@ -2,6 +2,8 @@
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)

+// I AM NOT DONE
+
 fn main() {
    // Characters (`char`)

--- a/exercises/primitive_types/primitive_types3.rs
+++ b/exercises/primitive_types/primitive_types3.rs
@@ -1,6 +1,8 @@
 // primitive_types3.rs
 // Create an array with at least 100 elements in it where the ??? is. 
-// Scroll down for hints!
+// Execute `rustlings hint primitive_types3` for hints!
+
+// I AM NOT DONE

 fn main() {
    let a = ???
@@ -11,37 +13,3 @@ fn main() {
        println!("Meh, I eat arrays like that for breakfast.");
    }
 }
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-// There's a shorthand to initialize Arrays with a certain size that does not 
-// require you to type in 100 items (but you certainly can if you want!).
-// For example, you can do:
-// let array = ["Are we there yet?"; 10];
-
-// Bonus: what are some other things you could have that would return true
-// for `a.len() >= 100`?
--- a/exercises/primitive_types/primitive_types4.rs
+++ b/exercises/primitive_types/primitive_types4.rs
@@ -1,68 +1,14 @@
 // primitive_types4.rs
-// Get a slice out of Array a where the ??? is so that the `if` statement
-// returns true. Scroll down for hints!!
+// Get a slice out of Array a where the ??? is so that the test passes.
+// Execute `rustlings hint primitive_types4` for hints!!
+
+// I AM NOT DONE

 #[test]
-fn main() {
+fn slice_out_of_array() {
    let a = [1, 2, 3, 4, 5];

    let nice_slice = ???

    assert_eq!([2, 3, 4], nice_slice)
 }
-
-
-
-
-
-
-
-
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-
-
-
-// Take a look at the Understanding Ownership -> Slices -> Other Slices section of the book:
-// https://doc.rust-lang.org/book/ch04-03-slices.html
-// and use the starting and ending indices of the items in the Array
-// that you want to end up in the slice.
-
-// If you're curious why the right hand of the `==` comparison does not
-// have an ampersand for a reference since the left hand side is a
-// reference, take a look at the Deref coercions section of the book:
-// https://doc.rust-lang.org/book/ch15-02-deref.html
--- a/exercises/primitive_types/primitive_types5.rs
+++ b/exercises/primitive_types/primitive_types5.rs
@@ -1,6 +1,8 @@
 // primitive_types5.rs
 // Destructure the `cat` tuple so that the println will work.
-// Scroll down for hints!
+// Execute `rustlings hint primitive_types5` for hints!
+
+// I AM NOT DONE

 fn main() {
    let cat = ("Furry McFurson", 3.5);
@@ -8,38 +10,3 @@ fn main() {

    println!("{} is {} years old.", name, age);
 }
-
-
-
-
-
-
-
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-
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-
-
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-
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-
-
-
-// Take a look at the Data Types -> The Tuple Type section of the book:
-// https://doc.rust-lang.org/book/ch03-02-data-types.html#the-tuple-type
-// Particularly the part about destructuring (second to last example in the section).
-// You'll need to make a pattern to bind `name` and `age` to the appropriate parts
-// of the tuple. You can do it!!
--- a/exercises/primitive_types/primitive_types6.rs
+++ b/exercises/primitive_types/primitive_types6.rs
@@ -1,45 +1,11 @@
 // primitive_types6.rs
 // Use a tuple index to access the second element of `numbers`.
 // You can put this right into the `println!` where the ??? is.
-// Scroll down for hints!
+// Execute `rustlings hint primitive_types6` for hints!
+
+// I AM NOT DONE

 fn main() {
    let numbers = (1, 2, 3);
    println!("The second number is {}", ???);
 }
-
-
-
-
-
-
-
-
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-
-
-
-
-// While you could use a destructuring `let` for the tuple here, try
-// indexing into it instead, as explained in the last example of the
-// Data Types -> The Tuple Type section of the book:
-// https://doc.rust-lang.org/book/ch03-02-data-types.html#the-tuple-type
-// Now you have another tool in your toolbox!
--- a/exercises/quiz1.rs
+++ b/exercises/quiz1.rs
@@ -1,12 +1,14 @@
-// test1.rs
-// This is a test for the following sections:
+// quiz1.rs
+// This is a quiz for the following sections:
 // - Variables
 // - Functions

-// Mary is buying apples. One apple usually costs 2 dollars, but if you buy
+// Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
 // more than 40 at once, each apple only costs 1! Write a function that calculates
 // the price of an order of apples given the order amount. No hints this time!

+// I AM NOT DONE
+
 // Put your function here!
 // fn ..... {

--- a/exercises/quiz2.rs
+++ b/exercises/quiz2.rs
@@ -1,12 +1,14 @@
-// strings3.rs
-// This is a test for the following sections:
+// quiz2.rs
+// This is a quiz for the following sections:
 // - Strings

-// Ok, here are a bunch of values-- some are `Strings`, some are `&strs`. Your
+// Ok, here are a bunch of values-- some are `String`s, some are `&str`s. Your
 // task is to call one of these two functions on each value depending on what
 // you think each value is. That is, add either `string_slice` or `string`
 // before the parentheses on each line. If you're right, it will compile!

+// I AM NOT DONE
+
 fn string_slice(arg: &str) {
    println!("{}", arg);
 }
--- a/exercises/quiz3.rs
+++ b/exercises/quiz3.rs
@@ -1,12 +1,14 @@
-// test2.rs
-// This is a test for the following sections:
+// quiz3.rs
+// This is a quiz for the following sections:
 // - Tests

-// This test isn't testing our function -- make it do that in such a way that
+// This quiz isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests that we get the result
 // we expect to get when we call `times_two` with a negative number.
 // No hints, you can do this :)

+// I AM NOT DONE
+
 pub fn times_two(num: i32) -> i32 {
    num * 2
 }
--- a/exercises/quiz4.rs
+++ b/exercises/quiz4.rs
@@ -0,0 +1,23 @@
+// quiz4.rs
+// This quiz covers the sections:
+// - Modules
+// - Macros
+
+// Write a macro that passes the quiz! No hints this time, you can do it!
+
+// I AM NOT DONE
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_my_macro_world() {
+        assert_eq!(my_macro!("world!"), "Hello world!");
+    }
+
+    #[test]
+    fn test_my_macro_goodbye() {
+        assert_eq!(my_macro!("goodbye!"), "Hello goodbye!");
+    }
+}
--- a/exercises/standard_library_types/README.md
+++ b/exercises/standard_library_types/README.md
@@ -1,5 +1,7 @@
+For the Box exercise check out the chapter [Using Box to Point to Data on the Heap](https://doc.rust-lang.org/book/ch15-01-box.html).
+
 For the Arc exercise check out the chapter [Shared-State Concurrency](https://doc.rust-lang.org/book/ch16-03-shared-state.html) of the Rust Book.

 For the Iterator exercise check out the chapters [Iterator](https://doc.rust-lang.org/book/ch13-02-iterators.html) of the Rust Book and the [Iterator documentation](https://doc.rust-lang.org/stable/std/iter/).
-Do not adjust your monitors-- iterators 1 and 2 are indeed missing. Iterator 3 is a bit challenging so we're leaving space for some exercises to lead up to it!
+Do not adjust your monitors-- iterators1.rs is indeed missing. Iterators is a challenging topic, so we're leaving space for a simpler exercise!

--- a/exercises/standard_library_types/arc1.rs
+++ b/exercises/standard_library_types/arc1.rs
@@ -1,9 +1,12 @@
 // arc1.rs
 // Make this code compile by filling in a value for `shared_numbers` where the
-// TODO comment is and creating an initial binding for `child_numbers`
+// TODO comment is and create an initial binding for `child_numbers`
 // somewhere. Try not to create any copies of the `numbers` Vec!
-// Scroll down for hints :)
+// Execute `rustlings hint arc1` for hints :)

+// I AM NOT DONE
+
+#![forbid(unused_imports)] // Do not change this, (or the next) line.
 use std::sync::Arc;
 use std::thread;

@@ -27,29 +30,3 @@ fn main() {
        handle.join().unwrap();
    }
 }
-
-
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-
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-
-
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-
-
-
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-
-
-
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-
-
-// Make `shared_numbers` be an `Arc` from the numbers vector. Then, in order
-// to avoid creating a copy of `numbers`, you'll need to create `child_numbers`
-// inside the loop but still in the main thread.
-
-// `child_numbers` should be a clone of the Arc of the numbers instead of a
-// thread-local copy of the numbers.
--- a/exercises/standard_library_types/box1.rs
+++ b/exercises/standard_library_types/box1.rs
@@ -0,0 +1,53 @@
+// box1.rs
+//
+// At compile time, Rust needs to know how much space a type takes up. This becomes problematic
+// for recursive types, where a value can have as part of itself another value of the same type.
+// To get around the issue, we can use a `Box` - a smart pointer used to store data on the heap,
+// which also allows us to wrap a recursive type.
+//
+// The recursive type we're implementing in this exercise is the `cons list` - a data structure
+// frequently found in functional programming languages. Each item in a cons list contains two
+// elements: the value of the current item and the next item. The last item is a value called `Nil`.
+//
+// Step 1: use a `Box` in the enum definition to make the code compile
+// Step 2: create both empty and non-empty cons lists by replacing `unimplemented!()`
+//
+// Note: the tests should not be changed
+//
+// Execute `rustlings hint box1` for hints :)
+
+// I AM NOT DONE
+
+#[derive(PartialEq, Debug)]
+pub enum List {
+    Cons(i32, List),
+    Nil,
+}
+
+fn main() {
+    println!("This is an empty cons list: {:?}", create_empty_list());
+    println!("This is a non-empty cons list: {:?}", create_non_empty_list());
+}
+
+pub fn create_empty_list() -> List {
+    unimplemented!()
+}
+
+pub fn create_non_empty_list() -> List {
+    unimplemented!()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_create_empty_list() {
+        assert_eq!(List::Nil, create_empty_list())
+    }
+
+    #[test]
+    fn test_create_non_empty_list() {
+        assert_ne!(create_empty_list(), create_non_empty_list())
+    }
+}
--- a/exercises/standard_library_types/iterators2.rs
+++ b/exercises/standard_library_types/iterators2.rs
@@ -1,9 +1,13 @@
 // iterators2.rs
-// In this module, you'll learn some of unique advantages that iterators can offer
-// Step 1. Complete the `capitalize_first` function to pass the first two cases
-// Step 2. Apply the `capitalize_first` function to a vector of strings, ensuring that it returns a vector of strings as well
-// Step 3. Apply the `capitalize_first` function again to a list, but try and ensure it returns a single string
-// As always, there are hints below!
+// In this module, you'll learn some of unique advantages that iterators can offer.
+// Step 1. Complete the `capitalize_first` function to pass the first two cases.
+// Step 2. Apply the `capitalize_first` function to a vector of strings.
+//         Ensure that it returns a vector of strings as well.
+// Step 3. Apply the `capitalize_first` function again to a list.
+//         Try to ensure it returns a single string.
+// As always, there are hints if you execute `rustlings hint iterators2`!
+
+// I AM NOT DONE

 pub fn capitalize_first(input: &str) -> String {
    let mut c = input.chars();
@@ -44,102 +48,3 @@ mod tests {
        assert_eq!(capitalized_words, "Hello World");
    }
 }
-
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-
-// Step 1
-// You need to call something on `first` before it can be collected
-// Currently its type is `char`. Have a look at the methods that are available on that type:
-// https://doc.rust-lang.org/std/primitive.char.html
-
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-// Step 2
-// First you'll need to turn the Vec into an iterator
-// Then you'll need to apply your function unto each item in the vector
-// P.s. Don't forget to collect() at the end!
-
-
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-// Step 3.
-// This is very similar to the previous test. The only real change is that you will need to
-// alter the type that collect is coerced into. For a bonus you could try doing this with a
-// turbofish
--- a/exercises/standard_library_types/iterators3.rs
+++ b/exercises/standard_library_types/iterators3.rs
@@ -4,10 +4,11 @@
 // 1. Complete the divide function to get the first four tests to pass
 // 2. Uncomment the last two tests and get them to pass by filling in
 //    values for `x` using `division_results`.
-// Scroll down for a minor hint for part 2, and scroll down further for
-// a major hint.
+// Execute `rustlings hint iterators3` to get some hints!
 // Have fun :-)

+// I AM NOT DONE
+
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
    NotDivisible(NotDivisibleError),
@@ -75,72 +76,3 @@ mod tests {
    }
    */
 }
-
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-
-// Minor hint: In each of the two cases in the match in main, you can create x with either
-// a 'turbofish' or by hinting the type of x to the compiler. You may try both.
-
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-// Major hint: Have a look at the Iter trait and at the explanation of its collect function.
-// Especially the part about Result is interesting.
--- a/exercises/standard_library_types/iterators4.rs
+++ b/exercises/standard_library_types/iterators4.rs
@@ -1,15 +1,17 @@
 // iterators4.rs

+// I AM NOT DONE
+
 pub fn factorial(num: u64) -> u64 {
-    // Complete this function to return factorial of num
+    // Complete this function to return the factorial of num
    // Do not use:
    // - return
-    // For extra fun don't use:
+    // Try not to use:
    // - imperative style loops (for, while)
    // - additional variables
-    // For the most fun don't use:
+    // For an extra challenge, don't use:
    // - recursion
-    // Scroll down for hints.
+    // Execute `rustlings hint iterators4` for hints.
 }

 #[cfg(test)]
@@ -30,32 +32,3 @@ mod tests {
        assert_eq!(24, factorial(4));
    }
 }
-
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-// In an imperative language you might write a for loop to iterate through
-// multiply the values into a mutable variable. Or you might write code more
-// functionally with recursion and a match clause. But you can also use ranges
-// and iterators to solve this in rust.
--- a/exercises/strings/strings1.rs
+++ b/exercises/strings/strings1.rs
@@ -1,5 +1,8 @@
 // strings1.rs
-// Make me compile without changing the function signature! Scroll down for hints :)
+// Make me compile without changing the function signature!
+// Execute `rustlings hint strings1` for hints ;)
+
+// I AM NOT DONE

 fn main() {
    let answer = current_favorite_color();
@@ -9,38 +12,3 @@ fn main() {
 fn current_favorite_color() -> String {
    "blue"
 }
-
-
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-
-// The `current_favorite_color` function is currently returning a string slice with the `'static`
-// lifetime. We know this because the data of the string lives in our code itself -- it doesn't
-// come from a file or user input or another program -- so it will live as long as our program
-// lives. But it is still a string slice. There's one way to create a `String` by converting a
-// string slice covered in the Strings chapter of the book, and another way that uses the `From`
-// trait.
--- a/exercises/strings/strings2.rs
+++ b/exercises/strings/strings2.rs
@@ -1,5 +1,8 @@
 // strings2.rs
-// Make me compile without changing the function signature! Scroll down for hints :)
+// Make me compile without changing the function signature!
+// Execute `rustlings hint strings2` for hints :)
+
+// I AM NOT DONE

 fn main() {
    let word = String::from("green"); // Try not changing this line :)
@@ -13,32 +16,3 @@ fn main() {
 fn is_a_color_word(attempt: &str) -> bool {
    attempt == "green" || attempt == "blue" || attempt == "red"
 }
-
-
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-
-
-// Yes, it would be really easy to fix this by just changing the value bound to `word` to be a
-// string slice instead of a `String`, wouldn't it?? There is a way to add one character to line
-// 6, though, that will coerce the `String` into a string slice.
--- a/exercises/structs/structs1.rs
+++ b/exercises/structs/structs1.rs
@@ -1,6 +1,8 @@
 // structs1.rs
 // Address all the TODOs to make the tests pass!

+// I AM NOT DONE
+
 struct ColorClassicStruct {
    // TODO: Something goes here
 }
@@ -26,7 +28,6 @@ mod tests {
    #[test]
    fn tuple_structs() {
        // TODO: Instantiate a tuple struct!
-        // For more fun, use the field initialization shorthand.
        // let green =

        assert_eq!(green.0, "green");
--- a/exercises/structs/structs2.rs
+++ b/exercises/structs/structs2.rs
@@ -1,6 +1,7 @@
 // structs2.rs
 // Address all the TODOs to make the tests pass!
-// No hints, just do it!
+
+// I AM NOT DONE

 #[derive(Debug)]
 struct Order {
--- a/exercises/structs/structs3.rs
+++ b/exercises/structs/structs3.rs
@@ -0,0 +1,67 @@
+// structs3.rs
+// Structs contain more than simply some data, they can also have logic, in this
+// exercise we have defined the Package struct and we want to test some logic attached to it,
+// make the code compile and the tests pass! If you have issues execute `rustlings hint structs3`
+
+// I AM NOT DONE
+
+#[derive(Debug)]
+struct Package {
+    sender_country: String,
+    recipient_country: String,
+    weight_in_grams: i32,
+}
+
+impl Package {
+    fn new(sender_country: String, recipient_country: String, weight_in_grams: i32) -> Package {
+        if weight_in_grams <= 0 {
+            // Something goes here...
+        } else {
+            return Package {sender_country, recipient_country, weight_in_grams};
+        }
+    }
+
+    fn is_international(&self) -> ??? {
+        // Something goes here...
+    }
+
+    fn get_fees(&self, cents_per_kg: i32) -> ??? {
+        // Something goes here... (beware of grams to kg conversion)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[should_panic]
+    fn fail_creating_weightless_package() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Austria");
+
+        Package::new(sender_country, recipient_country, -2210);
+    }
+
+    #[test]
+    fn create_international_package() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Russia");
+        
+        let package = Package::new(sender_country, recipient_country, 1200);
+
+        assert!(package.is_international());
+    }
+
+    #[test]
+    fn calculate_transport_fees() {
+        let sender_country = String::from("Spain");
+        let recipient_country = String::from("Spain");
+
+        let cents_per_kg = ???;
+        
+        let package = Package::new(sender_country, recipient_country, 1500);
+        
+        assert_eq!(package.get_fees(cents_per_kg), 4500);
+    }
+}
--- a/exercises/test4.rs
+++ b/exercises/test4.rs
@@ -1,12 +0,0 @@
-// test4.rs
-// This test covers the sections:
-// - Modules
-// - Macros
-
-// Write a macro that passes the test! No hints this time, you can do it!
-
-fn main() {
-    if my_macro!("world!") != "Hello world!" {
-        panic!("Oh no! Wrong output!");
-    }
-}
--- a/exercises/tests/tests1.rs
+++ b/exercises/tests/tests1.rs
@@ -1,10 +1,12 @@
 // tests1.rs
 // Tests are important to ensure that your code does what you think it should do.
 // Tests can be run on this file with the following command:
-// rustlings run --test exercises/tests/tests1.rs
+// rustlings run tests1

 // This test has a problem with it -- make the test compile! Make the test
-// pass! Make the test fail! Scroll down for hints :)
+// pass! Make the test fail! Execute `rustlings hint tests1` for hints :)
+
+// I AM NOT DONE

 #[cfg(test)]
 mod tests {
@@ -13,37 +15,3 @@ mod tests {
        assert!();
    }
 }
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-// You don't even need to write any code to test -- you can just test values and run that, even
-// though you wouldn't do that in real life :) `assert!` is a macro that needs an argument.
-// Depending on the value of the argument, `assert!` will do nothing (in which case the test will
-// pass) or `assert!` will panic (in which case the test will fail). So try giving different values
-// to `assert!` and see which ones compile, which ones pass, and which ones fail :)
--- a/exercises/tests/tests2.rs
+++ b/exercises/tests/tests2.rs
@@ -1,6 +1,8 @@
 // tests2.rs
 // This test has a problem with it -- make the test compile! Make the test
-// pass! Make the test fail! Scroll down for hints :)
+// pass! Make the test fail! Execute `rustlings hint tests2` for hints :)
+
+// I AM NOT DONE

 #[cfg(test)]
 mod tests {
@@ -9,36 +11,3 @@ mod tests {
        assert_eq!();
    }
 }
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-// Like the previous exercise, you don't need to write any code to get this test to compile and
-// run. `assert_eq!` is a macro that takes two arguments and compares them. Try giving it two
-// values that are equal! Try giving it two arguments that are different! Try giving it two values
-// that are of different types! Try switching which argument comes first and which comes second!
--- a/exercises/tests/tests3.rs
+++ b/exercises/tests/tests3.rs
@@ -1,7 +1,10 @@
 // tests3.rs
 // This test isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests whether we get the result
-// we expect to get when we call `is_even(5)`. Scroll down for hints!
+// we expect to get when we call `is_even(5)`.
+// Execute `rustlings hint tests3` for hints :)
+
+// I AM NOT DONE

 pub fn is_even(num: i32) -> bool {
    num % 2 == 0
@@ -16,28 +19,3 @@ mod tests {
        assert!();
    }
 }
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-// You can call a function right where you're passing arguments to `assert!` -- so you could do
-// something like `assert!(having_fun())`. If you want to check that you indeed get false, you
-// can negate the result of what you're doing using `!`, like `assert!(!having_fun())`.
--- a/exercises/threads/threads1.rs
+++ b/exercises/threads/threads1.rs
@@ -1,10 +1,12 @@
 // threads1.rs
-// Make this compile! Scroll down for hints :) The idea is the thread
-// spawned on line 19 is completing jobs while the main thread is
+// Make this compile! Execute `rustlings hint threads1` for hints :)
+// The idea is the thread spawned on line 21 is completing jobs while the main thread is
 // monitoring progress until 10 jobs are completed. If you see 6 lines
-// of "waiting..." and the program ends without timing out the playground,
+// of "waiting..." and the program ends without timing out when running,
 // you've got it :)

+// I AM NOT DONE
+
 use std::sync::Arc;
 use std::thread;
 use std::time::Duration;
@@ -27,69 +29,3 @@ fn main() {
        thread::sleep(Duration::from_millis(500));
    }
 }
-
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-// `Arc` is an Atomic Reference Counted pointer that allows safe, shared access
-// to **immutable** data. But we want to *change* the number of `jobs_completed`
-// so we'll need to also use another type that will only allow one thread to
-// mutate the data at a time. Take a look at this section of the book:
-// https://doc.rust-lang.org/book/ch16-03-shared-state.html#atomic-reference-counting-with-arct
-// and keep scrolling if you'd like more hints :)
-
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-// Do you now have an `Arc` `Mutex` `JobStatus` at the beginning of main? Like:
-// `let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));`
-// Similar to the code in the example in the book that happens after the text
-// that says "We can use Arc<T> to fix this.". If not, give that a try! If you
-// do and would like more hints, keep scrolling!!
-
-
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-// Make sure neither of your threads are holding onto the lock of the mutex
-// while they are sleeping, since this will prevent the other thread from
-// being allowed to get the lock. Locks are automatically released when
-// they go out of scope.
-
-// Ok, so, real talk, this was actually tricky for *me* to do too. And
-// I could see a lot of different problems you might run into, so at this
-// point I'm not sure which one you've hit :) Please see a few possible
-// answers on https://github.com/carols10cents/rustlings/issues/3 --
-// mine is a little more complicated because I decided I wanted to see
-// the number of jobs currently done when I was checking the status.
-
-// Please open an issue if you're still running into a problem that
-// these hints are not helping you with, or if you've looked at the sample
-// answers and don't understand why they work and yours doesn't.
-
-// If you've learned from the sample solutions, I encourage you to come
-// back to this exercise and try it again in a few days to reinforce
-// what you've learned :)
--- a/exercises/traits/README.md
+++ b/exercises/traits/README.md
@@ -0,0 +1,20 @@
+### Traits
+
+A trait is a collection of methods. 
+
+Data types can implement traits. To do so, the methods making up the trait are defined for the data type. For example, the `String` data type implements the `From<&str>` trait. This allows a user to write `String::from("hello")`.
+
+In this way, traits are somewhat similar to Java interfaces and C++ abstract classes.
+
+Some additional common Rust traits include:
+
+ `Clone` (the `clone` method), 
+ `Display` (which allows formatted display via `{}`), and
+ `Debug` (which allows formatted display via `{:?}`).
+
+Because traits indicate shared behavior between data types, they are useful when writing generics.
+
+
+#### Book Sections
+
+- [Traits](https://doc.rust-lang.org/book/ch10-02-traits.html)
--- a/exercises/traits/traits1.rs
+++ b/exercises/traits/traits1.rs
@@ -0,0 +1,44 @@
+// traits1.rs
+// Time to implement some traits!
+// 
+// Your task is to implement the trait
+// `AppendBar' for the type `String'.
+// 
+// The trait AppendBar has only one function,
+// which appends "Bar" to any object
+// implementing this trait.
+
+// I AM NOT DONE
+trait AppendBar {
+    fn append_bar(self) -> Self;
+}
+
+impl AppendBar for String {
+    //Add your code here
+
+}
+
+fn main() {
+    let s = String::from("Foo");
+    let s = s.append_bar();
+    println!("s: {}", s);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn is_FooBar() {
+        assert_eq!(String::from("Foo").append_bar(), String::from("FooBar"));
+    }
+
+    #[test]
+    fn is_BarBar() {
+        assert_eq!(
+            String::from("").append_bar().append_bar(),
+            String::from("BarBar")
+        );
+    }
+
+}
--- a/exercises/traits/traits2.rs
+++ b/exercises/traits/traits2.rs
@@ -0,0 +1,35 @@
+// traits2.rs
+// 
+// Your task is to implement the trait
+// `AppendBar' for a vector of strings.
+// 
+// To implement this trait, consider for
+// a moment what it means to 'append "Bar"'
+// to a vector of strings.
+// 
+// No boiler plate code this time,
+// you can do this!
+
+// I AM NOT DONE
+
+trait AppendBar {
+    fn append_bar(self) -> Self;
+}
+
+//TODO: Add your code here
+
+
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn is_vec_pop_eq_bar() {
+        let mut foo = vec![String::from("Foo")].append_bar();
+        assert_eq!(foo.pop().unwrap(), String::from("Bar"));
+        assert_eq!(foo.pop().unwrap(), String::from("Foo"));
+    }
+
+}
--- a/exercises/variables/variables1.rs
+++ b/exercises/variables/variables1.rs
@@ -1,42 +1,14 @@
 // variables1.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables1` if you want a hint :)
+
+// 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.
+
+// I AM NOT DONE

 fn main() {
    x = 5;
    println!("x has the value {}", x);
 }
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-// Hint: The declaration on line 5 is missing a keyword that is needed in Rust
-// to create a new variable binding.
--- a/exercises/variables/variables2.rs
+++ b/exercises/variables/variables2.rs
@@ -1,5 +1,7 @@
 // variables2.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables2` if you want a hint :)
+
+// I AM NOT DONE

 fn main() {
    let x;
@@ -9,39 +11,3 @@ fn main() {
        println!("Not ten!");
    }
 }
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-// The compiler message is saying that Rust cannot infer the type that the
-// variable binding `x` has with what is given here.
-// What happens if you annotate line 5 with a type annotation?
-// What if you give x a value?
-// What if you do both?
-// What type should x be, anyway?
-// What if x is the same type as 10? What if it's a different type?
--- a/exercises/variables/variables3.rs
+++ b/exercises/variables/variables3.rs
@@ -1,43 +1,11 @@
 // variables3.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables3` if you want a hint :)
+
+// I AM NOT DONE

 fn main() {
    let x = 3;
    println!("Number {}", x);
-    x = 5;
+    x = 5; // don't change this line
    println!("Number {}", x);
 }
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-// In Rust, variable bindings are immutable by default. But here we're trying
-// to reassign a different value to x! There's a keyword we can use to make
-// a variable binding mutable instead.
--- a/exercises/variables/variables4.rs
+++ b/exercises/variables/variables4.rs
@@ -1,45 +1,9 @@
 // variables4.rs
-// Make me compile! Scroll down for hints :)
+// Make me compile! Execute the command `rustlings hint variables4` if you want a hint :)
+
+// I AM NOT DONE

 fn main() {
    let x: i32;
    println!("Number {}", x);
 }
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-// Oops! In this exercise, we have a variable binding that we've created on
-// line 5, and we're trying to use it on line 6, but we haven't given it a
-// value. We can't print out something that isn't there; try giving x a value!
-// This is an error that can cause bugs that's very easy to make in any
-// programming language -- thankfully the Rust compiler has caught this for us!
--- a/exercises/variables/variables5.rs
+++ b/exercises/variables/variables5.rs
@@ -0,0 +1,11 @@
+// variables5.rs
+// Make me compile! Execute the command `rustlings hint variables5` if you want a hint :)
+
+// I AM NOT DONE
+
+fn main() {
+    let number = "3"; // don't change this line
+    println!("Number {}", number);
+    number = 3;
+    println!("Number {}", number);
+}
--- a/exercises/variables/variables6.rs
+++ b/exercises/variables/variables6.rs
@@ -0,0 +1,9 @@
+// variables6.rs
+// Make me compile! Execute the command `rustlings hint variables6` if you want a hint :)
+
+// I AM NOT DONE
+
+const NUMBER = 3;
+fn main() {
+    println!("Number {}", NUMBER);
+}
--- a/info.toml
+++ b/info.toml
@@ -1,241 +1,824 @@
 # VARIABLES

 [[exercises]]
+name = "variables1"
 path = "exercises/variables/variables1.rs"
 mode = "compile"
+hint = """
+Hint: The declaration on line 12 is missing a keyword that is needed in Rust
+to create a new variable binding."""

 [[exercises]]
+name = "variables2"
 path = "exercises/variables/variables2.rs"
 mode = "compile"
+hint = """
+The compiler message is saying that Rust cannot infer the type that the
+variable binding `x` has with what is given here.
+What happens if you annotate line 7 with a type annotation?
+What if you give x a value?
+What if you do both?
+What type should x be, anyway?
+What if x is the same type as 10? What if it's a different type?"""

 [[exercises]]
+name = "variables3"
 path = "exercises/variables/variables3.rs"
 mode = "compile"
+hint = """
+In Rust, variable bindings are immutable by default. But here we're trying
+to reassign a different value to x! There's a keyword we can use to make
+a variable binding mutable instead."""

 [[exercises]]
+name = "variables4"
 path = "exercises/variables/variables4.rs"
 mode = "compile"
+hint = """
+Oops! In this exercise, we have a variable binding that we've created on
+line 7, and we're trying to use it on line 8, but we haven't given it a
+value. We can't print out something that isn't there; try giving x a value!
+This is an error that can cause bugs that's very easy to make in any
+programming language -- thankfully the Rust compiler has caught this for us!"""
+
+[[exercises]]
+name = "variables5"
+path = "exercises/variables/variables5.rs"
+mode = "compile"
+hint = """
+In variables3 we already learned how to make an immutable variable mutable
+using a special keyword. Unfortunately this doesn't help us much in this exercise
+because we want to assign a different typed value to an existing variable. Sometimes
+you may also like to reuse existing variable names because you are just converting
+values to different types like in this exercise.
+Fortunately Rust has a powerful solution to this problem: 'Shadowing'!
+You can read more about 'Shadowing' in the book's section 'Variables and Mutability': 
+https://doc.rust-lang.org/book/ch03-01-variables-and-mutability.html#shadowing
+Try to solve this exercise afterwards using this technique."""
+
+[[exercises]]
+name = "variables6"
+path = "exercises/variables/variables6.rs"
+mode = "compile"
+hint = """
+We know about variables and mutability, but there is another important type of 
+variable available; constants. 
+Constants are always immutable and they are declared with keyword 'const' rather 
+than keyword 'let'.
+Constants types must also always be annotated.
+
+Read more about constants under 'Differences Between Variables and Constants' in the book's section 'Variables and Mutability': 
+https://doc.rust-lang.org/book/ch03-01-variables-and-mutability.html#differences-between-variables-and-constants
+"""

 # IF

 [[exercises]]
+name = "if1"
 path = "exercises/if/if1.rs"
 mode = "test"
+hint = """
+It's possible to do this in one line if you would like!
+Some similar examples from other languages:
+- In C(++) this would be: `a > b ? a : b`
+- In Python this would be:  `a if a > b else b`
+Remember in Rust that:
+- the `if` condition does not need to be surrounded by parentheses
+- `if`/`else` conditionals are expressions
+- Each condition is followed by a `{}` block."""
+
+[[exercises]]
+name = "if2"
+path = "exercises/if/if2.rs"
+mode = "test"
+hint = """
+For that first compiler error, it's important in Rust that each conditional
+block return the same type! To get the tests passing, you will need a couple
+conditions checking different input values."""

 # FUNCTIONS

 [[exercises]]
+name = "functions1"
 path = "exercises/functions/functions1.rs"
 mode = "compile"
+hint = """
+This main function is calling a function that it expects to exist, but the
+function doesn't exist. It expects this function to have the name `call_me`.
+It expects this function to not take any arguments and not return a value.
+Sounds a lot like `main`, doesn't it?"""

 [[exercises]]
+name = "functions2"
 path = "exercises/functions/functions2.rs"
 mode = "compile"
+hint = """
+Rust requires that all parts of a function's signature have type annotations,
+but `call_me` is missing the type annotation of `num`."""

 [[exercises]]
+name = "functions3"
 path = "exercises/functions/functions3.rs"
 mode = "compile"
+hint = """
+This time, the function *declaration* is okay, but there's something wrong
+with the place where we're calling the function."""

 [[exercises]]
+name = "functions4"
 path = "exercises/functions/functions4.rs"
 mode = "compile"
+hint = """
+The error message points to line 14 and says it expects a type after the
+`->`. This is where the function's return type should be-- take a look at
+the `is_even` function for an example!"""

 [[exercises]]
+name = "functions5"
 path = "exercises/functions/functions5.rs"
 mode = "compile"
+hint = """
+This is a really common error that can be fixed by removing one character.
+It happens because Rust distinguishes between expressions and statements: expressions return
+a value based on its operand, and statements simply return a () type which behaves just like `void` in C/C++ language.
+We want to return a value of `i32` type from the `square` function, but it is returning a `()` type...
+They are not the same. There are two solutions:
+1. Add a `return` ahead of `num * num;`
+2. remove `;`, make it to be `num * num`"""

 # TEST 1

 [[exercises]]
-path = "exercises/test1.rs"
+name = "quiz1"
+path = "exercises/quiz1.rs"
 mode = "test"
+hint = "No hints this time ;)"

 # PRIMITIVE TYPES

 [[exercises]]
+name = "primitive_types1"
 path = "exercises/primitive_types/primitive_types1.rs"
 mode = "compile"
+hint = "No hints this time ;)"

 [[exercises]]
+name = "primitive_types2"
 path = "exercises/primitive_types/primitive_types2.rs"
 mode = "compile"
+hint = "No hints this time ;)"

 [[exercises]]
+name = "primitive_types3"
 path = "exercises/primitive_types/primitive_types3.rs"
 mode = "compile"
+hint = """
+There's a shorthand to initialize Arrays with a certain size that does not
+require you to type in 100 items (but you certainly can if you want!).
+For example, you can do:
+let array = ["Are we there yet?"; 10];
+
+Bonus: what are some other things you could have that would return true
+for `a.len() >= 100`?"""

 [[exercises]]
+name = "primitive_types4"
 path = "exercises/primitive_types/primitive_types4.rs"
 mode = "test"
+hint = """
+Take a look at the Understanding Ownership -> Slices -> Other Slices section of the book:
+https://doc.rust-lang.org/book/ch04-03-slices.html
+and use the starting and ending indices of the items in the Array
+that you want to end up in the slice.
+
+If you're curious why the first argument of `assert_eq!` does not
+have an ampersand for a reference since the second argument is a
+reference, take a look at the Deref coercions section of the book:
+https://doc.rust-lang.org/book/ch15-02-deref.html"""

 [[exercises]]
+name = "primitive_types5"
 path = "exercises/primitive_types/primitive_types5.rs"
 mode = "compile"
+hint = """
+Take a look at the Data Types -> The Tuple Type section of the book:
+https://doc.rust-lang.org/book/ch03-02-data-types.html#the-tuple-type
+Particularly the part about destructuring (second to last example in the section).
+You'll need to make a pattern to bind `name` and `age` to the appropriate parts
+of the tuple. You can do it!!"""

 [[exercises]]
+name = "primitive_types6"
 path = "exercises/primitive_types/primitive_types6.rs"
 mode = "compile"
+hint = """
+While you could use a destructuring `let` for the tuple here, try
+indexing into it instead, as explained in the last example of the
+Data Types -> The Tuple Type section of the book:
+https://doc.rust-lang.org/book/ch03-02-data-types.html#the-tuple-type
+Now you have another tool in your toolbox!"""

 # STRUCTS

 [[exercises]]
+name = "structs1"
 path = "exercises/structs/structs1.rs"
 mode = "test"
+hint = """
+Rust has more than one type of struct. Both variants are used to package related data together.
+On the one hand, there are normal, or classic, structs. These are named collections of related data stored in fields.
+The other variant is tuple structs. Basically just named tuples.
+In this exercise you need to implement one of each kind.
+
+Read more about structs in The Book: https://doc.rust-lang.org/stable/book/ch05-00-structs.html"""

 [[exercises]]
+name = "structs2"
 path = "exercises/structs/structs2.rs"
 mode = "test"
-
-# ENUMS
+hint = """
+Creating instances of structs is easy, all you need to do is assign some values to its fields. 
+There is however some shortcuts that can be taken when instantiating structs. 
+Have a look in The Book, to find out more: https://doc.rust-lang.org/stable/book/ch05-01-defining-structs.html#creating-instances-from-other-instances-with-struct-update-syntax"""

 [[exercises]]
-path = "exercises/enums/enums1.rs"
-mode = "compile"
-
-[[exercises]]
-path = "exercises/enums/enums2.rs"
-mode = "compile"
-
-[[exercises]]
-path = "exercises/enums/enums3.rs"
+name = "structs3"
+path = "exercises/structs/structs3.rs"
 mode = "test"
+hint = """
+The new method needs to panic if the weight is physically impossible :), how do we do that in Rust?

-# TESTS
+For is_international: What makes a package international? Seems related to the places it goes through right?

-[[exercises]]
-path = "exercises/tests/tests1.rs"
-mode = "test"
+For calculate_transport_fees: Bigger is more expensive usually, we don't have size, but something may fit the bill here :)

-[[exercises]]
-path = "exercises/tests/tests2.rs"
-mode = "test"
-
-[[exercises]]
-path = "exercises/tests/tests3.rs"
-mode = "test"
-
-# TEST 2
-
-[[exercises]]
-path = "exercises/test2.rs"
-mode = "test"
+Have a look in The Book, to find out more about method implementations: https://doc.rust-lang.org/book/ch05-03-method-syntax.html"""

 # STRINGS

 [[exercises]]
+name = "strings1"
 path = "exercises/strings/strings1.rs"
 mode = "compile"
+hint = """
+The `current_favorite_color` function is currently returning a string slice with the `'static`
+lifetime. We know this because the data of the string lives in our code itself -- it doesn't
+come from a file or user input or another program -- so it will live as long as our program
+lives. But it is still a string slice. There's one way to create a `String` by converting a
+string slice covered in the Strings chapter of the book, and another way that uses the `From`
+trait."""

 [[exercises]]
+name = "strings2"
 path = "exercises/strings/strings2.rs"
 mode = "compile"
+hint = """
+Yes, it would be really easy to fix this by just changing the value bound to `word` to be a
+string slice instead of a `String`, wouldn't it?? There is a way to add one character to line
+9, though, that will coerce the `String` into a string slice."""
+
+# TEST 2
+
+[[exercises]]
+name = "quiz2"
+path = "exercises/quiz2.rs"
+mode = "compile"
+hint = "No hints this time ;)"
+
+# ENUMS
+
+[[exercises]]
+name = "enums1"
+path = "exercises/enums/enums1.rs"
+mode = "compile"
+hint = """
+Hint: The declaration of the enumeration type has not been defined yet."""
+
+[[exercises]]
+name = "enums2"
+path = "exercises/enums/enums2.rs"
+mode = "compile"
+hint = """
+Hint: you can create enumerations that have different variants with different types
+such as no data, anonymous structs, a single string, tuples, ...etc"""
+
+[[exercises]]
+name = "enums3"
+path = "exercises/enums/enums3.rs"
+mode = "test"
+hint = "No hints this time ;)"
+
+# TESTS
+
+[[exercises]]
+name = "tests1"
+path = "exercises/tests/tests1.rs"
+mode = "test"
+hint = """
+You don't even need to write any code to test -- you can just test values and run that, even
+though you wouldn't do that in real life :) `assert!` is a macro that needs an argument.
+Depending on the value of the argument, `assert!` will do nothing (in which case the test will
+pass) or `assert!` will panic (in which case the test will fail). So try giving different values
+to `assert!` and see which ones compile, which ones pass, and which ones fail :)"""
+
+[[exercises]]
+name = "tests2"
+path = "exercises/tests/tests2.rs"
+mode = "test"
+hint = """
+Like the previous exercise, you don't need to write any code to get this test to compile and
+run. `assert_eq!` is a macro that takes two arguments and compares them. Try giving it two
+values that are equal! Try giving it two arguments that are different! Try giving it two values
+that are of different types! Try switching which argument comes first and which comes second!"""
+
+[[exercises]]
+name = "tests3"
+path = "exercises/tests/tests3.rs"
+mode = "test"
+hint = """
+You can call a function right where you're passing arguments to `assert!` -- so you could do
+something like `assert!(having_fun())`. If you want to check that you indeed get false, you
+can negate the result of what you're doing using `!`, like `assert!(!having_fun())`."""

 # TEST 3

 [[exercises]]
-path = "exercises/test3.rs"
-mode = "compile"
+name = "quiz3"
+path = "exercises/quiz3.rs"
+mode = "test"
+hint = "No hints this time ;)"

 # MODULES

 [[exercises]]
+name = "modules1"
 path = "exercises/modules/modules1.rs"
 mode = "compile"
+hint = """
+Everything is private in Rust by default-- but there's a keyword we can use
+to make something public! The compiler error should point to the thing that
+needs to be public."""

 [[exercises]]
+name = "modules2"
 path = "exercises/modules/modules2.rs"
 mode = "compile"
+hint = """
+The delicious_snacks module is trying to present an external
+interface (the `fruit` and `veggie` constants) that is different than
+its internal structure (the `fruits` and `veggies` modules and
+associated constants). It's almost there except for one keyword missing for
+each constant."""

 # MACROS

 [[exercises]]
+name = "macros1"
 path = "exercises/macros/macros1.rs"
 mode = "compile"
+hint = """
+When you call a macro, you need to add something special compared to a
+regular function call. If you're stuck, take a look at what's inside
+`my_macro`."""

 [[exercises]]
+name = "macros2"
 path = "exercises/macros/macros2.rs"
 mode = "compile"
+hint = """
+Macros don't quite play by the same rules as the rest of Rust, in terms of
+what's available where.
+
+Unlike other things in Rust, the order of "where you define a macro" versus
+"where you use it" actually matters."""

 [[exercises]]
+name = "macros3"
 path = "exercises/macros/macros3.rs"
 mode = "compile"
+hint = """
+In order to use a macro outside of its module, you need to do something
+special to the module to lift the macro out into its parent.
+
+The same trick also works on "extern crate" statements for crates that have
+exported macros, if you've seen any of those around."""

 [[exercises]]
+name = "macros4"
 path = "exercises/macros/macros4.rs"
 mode = "compile"
-
+hint = """
+You only need to add a single character to make this compile.
+The way macros are written, it wants to see something between each
+"macro arm", so it can separate them."""
 # TEST 4

 [[exercises]]
-path = "exercises/test4.rs"
-mode = "compile"
+name = "quiz4"
+path = "exercises/quiz4.rs"
+mode = "test"
+hint = "No hints this time ;)"

 # MOVE SEMANTICS

 [[exercises]]
+name = "move_semantics1"
 path = "exercises/move_semantics/move_semantics1.rs"
 mode = "compile"
+hint = """
+So you've got the "cannot borrow immutable local variable `vec1` as mutable" error on line 13,
+right? The fix for this is going to be adding one keyword, and the addition is NOT on line 13
+where the error is."""

 [[exercises]]
+name = "move_semantics2"
 path = "exercises/move_semantics/move_semantics2.rs"
 mode = "compile"
+hint = """
+So `vec0` is being *moved* into the function `fill_vec` when we call it on
+line 10, which means it gets dropped at the end of `fill_vec`, which means we
+can't use `vec0` again on line 13 (or anywhere else in `main` after the
+`fill_vec` call for that matter). We could fix this in a few ways, try them
+all!
+1. Make another, separate version of the data that's in `vec0` and pass that
+   to `fill_vec` instead.
+2. Make `fill_vec` borrow its argument instead of taking ownership of it,
+   and then copy the data within the function in order to return an owned
+   `Vec<i32>`
+3. Make `fill_vec` *mutably* borrow its argument (which will need to be
+   mutable), modify it directly, then not return anything. Then you can get rid
+   of `vec1` entirely -- note that this will change what gets printed by the
+   first `println!`"""

 [[exercises]]
+name = "move_semantics3"
 path = "exercises/move_semantics/move_semantics3.rs"
 mode = "compile"
+hint = """
+The difference between this one and the previous ones is that the first line
+of `fn fill_vec` that had `let mut vec = vec;` is no longer there. You can,
+instead of adding that line back, add `mut` in one place that will change
+an existing binding to be a mutable binding instead of an immutable one :)"""

 [[exercises]]
+name = "move_semantics4"
 path = "exercises/move_semantics/move_semantics4.rs"
 mode = "compile"
+hint = """
+Stop reading whenever you feel like you have enough direction :) Or try
+doing one step and then fixing the compiler errors that result!
+So the end goal is to:
+   - get rid of the first line in main that creates the new vector
+   - so then `vec0` doesn't exist, so we can't pass it to `fill_vec`
+   - we don't want to pass anything to `fill_vec`, so its signature should
+     reflect that it does not take any arguments
+   - since we're not creating a new vec in `main` anymore, we need to create
+     a new vec in `fill_vec`, similarly to the way we did in `main`"""

 # ERROR HANDLING

 [[exercises]]
+name = "errors1"
 path = "exercises/error_handling/errors1.rs"
 mode = "test"
+hint = """
+`Err` is one of the variants of `Result`, so what the 2nd test is saying
+is that `generate_nametag_text` should return a `Result` instead of an
+`Option`.
+
+To make this change, you'll need to:
+   - update the return type in the function signature to be a Result<String, String> that
+     could be the variants `Ok(String)` and `Err(String)`
+   - change the body of the function to return `Ok(stuff)` where it currently
+     returns `Some(stuff)`
+   - change the body of the function to return `Err(error message)` where it
+     currently returns `None`
+   - change the first test to expect `Ok(stuff)` where it currently expects
+     `Some(stuff)`."""

 [[exercises]]
+name = "errors2"
 path = "exercises/error_handling/errors2.rs"
 mode = "test"
+hint = """
+One way to handle this is using a `match` statement on
+`item_quantity.parse::<i32>()` where the cases are `Ok(something)` and
+`Err(something)`. This pattern is very common in Rust, though, so there's
+a `?` operator that does pretty much what you would make that match statement
+do for you! Take a look at this section of the Error Handling chapter:
+https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
+and give it a try!"""

 [[exercises]]
+name = "errors3"
 path = "exercises/error_handling/errors3.rs"
 mode = "test"
+hint = """
+If other functions can return a `Result`, why shouldn't `main`?"""

 [[exercises]]
+name = "errorsn"
 path = "exercises/error_handling/errorsn.rs"
 mode = "test"
+hint = """
+First hint: To figure out what type should go where the ??? is, take a look
+at the test helper function `test_with_str`, since it returns whatever
+`read_and_validate` returns and `test_with_str` has its signature fully
+specified.
+
+
+Next hint: There are three places in `read_and_validate` that we call a
+function that returns a `Result` (that is, the functions might fail).
+Apply the `?` operator on those calls so that we return immediately from
+`read_and_validate` if those function calls fail.
+
+
+Another hint: under the hood, the `?` operator calls `From::from`
+on the error value to convert it to a boxed trait object, a Box<dyn error::Error>,
+which is polymorphic-- that means that lots of different kinds of errors
+can be returned from the same function because all errors act the same
+since they all implement the `error::Error` trait.
+Check out this section of the book:
+https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
+
+
+Another another hint: Note that because the `?` operator returns
+the *unwrapped* value in the `Ok` case, if we want to return a `Result` from
+`read_and_validate` for *its* success case, we'll have to rewrap a value
+that we got from the return value of a `?`ed call in an `Ok`-- this will
+look like `Ok(something)`.
+
+
+Another another another hint: `Result`s must be "used", that is, you'll
+get a warning if you don't handle a `Result` that you get in your
+function. Read more about that in the `std::result` module docs:
+https://doc.rust-lang.org/std/result/#results-must-be-used"""

 # OPTIONS / RESULTS

 [[exercises]]
-path = "exercises/error_handling/option1.rs"
-mode = "test"
+name = "option1"
+path = "exercises/option/option1.rs"
+mode = "compile"
+hint = """
+Hint 1: Check out some functions of Option:
+is_some
+is_none
+unwrap
+
+and:
+pattern matching
+
+Hint 2: There are no sensible defaults for the value of an Array; the values need to be filled before use.
+"""

 [[exercises]]
+name = "option2"
+path = "exercises/option/option2.rs"
+mode = "compile"
+hint = """
+check out:
+https://doc.rust-lang.org/rust-by-example/flow_control/if_let.html
+https://doc.rust-lang.org/rust-by-example/flow_control/while_let.html
+
+Remember that Options can be stacked in if let and while let.
+For example: Some(Some(variable)) = variable2
+
+
+"""
+
+[[exercises]]
+name = "result1"
 path = "exercises/error_handling/result1.rs"
 mode = "test"
+hint = """
+`PositiveNonzeroInteger::new` is always creating a new instance and returning an `Ok` result.
+It should be doing some checking, returning an `Err` result if those checks fail, and only
+returning an `Ok` result if those checks determine that everything is... okay :)"""

-# THREADS
+#  CLIPPY

 [[exercises]]
-path = "exercises/threads/threads1.rs"
-mode = "compile"
+name = "clippy1"
+path = "exercises/clippy/clippy1.rs"
+mode = "clippy"
+hint = """
+Floating point calculations are usually imprecise, so asking if two values are exactly equal is asking for trouble"""
+
+[[exercises]]
+name = "clippy2"
+path = "exercises/clippy/clippy2.rs"
+mode = "clippy"
+hint = """
+`for` loops over Option values are more clearly expressed as an `if let`"""

 # STANDARD LIBRARY TYPES

 [[exercises]]
+name = "box1"
+path = "exercises/standard_library_types/box1.rs"
+mode = "test"
+hint = """
+Step 1
+The compiler's message should help: since we cannot store the value of the actual type
+when working with recursive types, we need to store a reference (pointer) to its value.
+We should, therefore, place our `List` inside a `Box`. More details in the book here:
+https://doc.rust-lang.org/book/ch15-01-box.html#enabling-recursive-types-with-boxes
+
+Step 2
+Creating an empty list should be fairly straightforward (hint: peek at the assertions).
+For a non-empty list keep in mind that we want to use our Cons "list builder".
+Although the current list is one of integers (i32), feel free to change the definition
+and try other types!
+"""
+
+[[exercises]]
+name = "arc1"
 path = "exercises/standard_library_types/arc1.rs"
 mode = "compile"
+hint = """
+Make `shared_numbers` be an `Arc` from the numbers vector. Then, in order
+to avoid creating a copy of `numbers`, you'll need to create `child_numbers`
+inside the loop but still in the main thread.
+
+`child_numbers` should be a clone of the Arc of the numbers instead of a
+thread-local copy of the numbers."""

 [[exercises]]
+name = "iterators2"
 path = "exercises/standard_library_types/iterators2.rs"
 mode = "test"
+hint = """
+Step 1
+You need to call something on `first` before it can be collected
+Currently its type is `char`. Have a look at the methods that are available on that type:
+https://doc.rust-lang.org/std/primitive.char.html
+
+
+Step 2
+First you'll need to turn the Vec into an iterator
+Then you'll need to apply your function unto each item in the vector
+P.s. Don't forget to collect() at the end!
+
+
+Step 3.
+This is very similar to the previous test. The only real change is that you will need to
+alter the type that collect is coerced into. For a bonus you could try doing this with a
+turbofish"""

 [[exercises]]
+name = "iterators3"
 path = "exercises/standard_library_types/iterators3.rs"
 mode = "test"
+hint = """
+Minor hint: In each of the two cases in the match in main, you can create x with either
+a 'turbofish' or by hinting the type of x to the compiler. You may try both.
+
+Major hint: Have a look at the Iter trait and at the explanation of its collect function.
+Especially the part about Result is interesting."""

 [[exercises]]
+name = "iterators4"
 path = "exercises/standard_library_types/iterators4.rs"
 mode = "test"
+hint = """
+In an imperative language, you might write a for loop that updates 
+a mutable variable. Or, you might write code utilizing recursion 
+and a match clause. In Rust you can take another functional
+approach, computing the factorial elegantly with ranges and iterators."""
+
+# TRAITS
+
+[[exercises]]
+name = "traits1"
+path = "exercises/traits/traits1.rs"
+mode = "test"
+hint = """
+A discussion about Traits in Rust can be found at:
+https://doc.rust-lang.org/book/ch10-02-traits.html
+"""
+
+[[exercises]]
+name = "traits2"
+path = "exercises/traits/traits2.rs"
+mode = "test"
+hint = """
+Notice how the trait takes ownership of 'self',and returns `Self'. 
+Try mutating the incoming string vector.
+
+Vectors provide suitable methods for adding an element at the end. See 
+the documentation at: https://doc.rust-lang.org/std/vec/struct.Vec.html"""
+
+# Generics
+
+[[exercises]]
+name = "generics1"
+path = "exercises/generics/generics1.rs"
+mode = "compile"
+hint = """
+Vectors in rust make use of generics to create dynamically sized arrays of any type.
+You need to tell the compiler what type we are pushing onto this vector."""
+
+[[exercises]]
+name = "generics2"
+path = "exercises/generics/generics2.rs"
+mode = "test"
+hint = """
+Currently we are wrapping only values of type 'u32'. 
+Maybe we could update the explicit references to this data type somehow?
+
+If you are still stuck https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-method-definitions
+"""
+
+[[exercises]]
+name = "generics3"
+path = "exercises/generics/generics3.rs"
+mode = "test"
+hint = """
+To find the best solution to this challenge you're going to need to think back to your 
+knowledge of traits, specifically Trait Bound Syntax -  you may also need this: "use std::fmt::Display;"
+
+This is definitely harder than the last two exercises! You need to think about not only making the
+ReportCard struct generic, but also the correct property - you will need to change the implementation
+of the struct slightly too...you can do it!
+"""
+
+# THREADS
+
+[[exercises]]
+name = "threads1"
+path = "exercises/threads/threads1.rs"
+mode = "compile"
+hint = """
+`Arc` is an Atomic Reference Counted pointer that allows safe, shared access
+to **immutable** data. But we want to *change* the number of `jobs_completed`
+so we'll need to also use another type that will only allow one thread to
+mutate the data at a time. Take a look at this section of the book:
+https://doc.rust-lang.org/book/ch16-03-shared-state.html#atomic-reference-counting-with-arct
+and keep reading if you'd like more hints :)
+
+
+Do you now have an `Arc` `Mutex` `JobStatus` at the beginning of main? Like:
+`let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));`
+Similar to the code in the example in the book that happens after the text
+that says "We can use Arc<T> to fix this.". If not, give that a try! If you
+do and would like more hints, keep reading!!
+
+
+Make sure neither of your threads are holding onto the lock of the mutex
+while they are sleeping, since this will prevent the other thread from
+being allowed to get the lock. Locks are automatically released when
+they go out of scope.
+
+Ok, so, real talk, this was actually tricky for *me* to do too. And
+I could see a lot of different problems you might run into, so at this
+point I'm not sure which one you've hit :)
+
+Please open an issue if you're still running into a problem that
+these hints are not helping you with, or if you've looked at the sample
+answers and don't understand why they work and yours doesn't.
+
+If you've learned from the sample solutions, I encourage you to come
+back to this exercise and try it again in a few days to reinforce
+what you've learned :)"""
+
+# TYPE CONVERSIONS
+
+[[exercises]]
+name = "using_as"
+path = "exercises/conversions/using_as.rs"
+mode = "compile"
+hint = """
+Use the `as` operator to cast one of the operands in the last line of the
+`average` function into the expected return type."""
+
+[[exercises]]
+name = "from_into"
+path = "exercises/conversions/from_into.rs"
+mode = "test"
+hint = """
+Follow the steps provided right before the `From` implementation"""
+
+[[exercises]]
+name = "try_from_into"
+path = "exercises/conversions/try_from_into.rs"
+mode = "test"
+hint = """
+Follow the steps provided right before the `TryFrom` implementation.
+You can also use the example at https://doc.rust-lang.org/std/convert/trait.TryFrom.html"""
+
+[[exercises]]
+name = "as_ref_mut"
+path = "exercises/conversions/as_ref_mut.rs"
+mode = "test"
+hint = """
+Add AsRef<str> as a trait bound to the functions."""
+
+[[exercises]]
+name = "from_str"
+path = "exercises/conversions/from_str.rs"
+mode = "test"
+hint = """
+The implementation of FromStr should return an Ok with a Person object,
+or an Err with a string if the string is not valid.
+This is almost like the `try_from_into` exercise."""
--- a/install.ps1
+++ b/install.ps1
@@ -72,6 +72,7 @@ if (!($LASTEXITCODE -eq 0)) {
 # but anyone running pwsh 5 will have to pass the argument.
 $version = Invoke-WebRequest -UseBasicParsing https://api.github.com/repos/rust-lang/rustlings/releases/latest `
    | ConvertFrom-Json | Select-Object -ExpandProperty tag_name
+
 Write-Host "Checking out version $version..."
 Set-Location $path
 git checkout -q tags/$version
@@ -82,4 +83,12 @@ if (!(Get-Command rustlings -ErrorAction SilentlyContinue)) {
    Write-Host "WARNING: Please check that you have '~/.cargo/bin' in your PATH environment variable!"
 }

+# Checking whether Clippy is installed.
+# Due to a bug in Cargo, this must be done with Rustup: https://github.com/rust-lang/rustup/issues/1514
+$clippy = (rustup component list | Select-String "clippy" | Select-String "installed") | Out-String
+if (!$clippy) {
+    Write-Host "Installing the 'cargo-clippy' executable..."
+    rustup component add clippy
+}
+
 Write-Host "All done! Run 'rustlings' to get started."
--- a/install.sh
+++ b/install.sh
@@ -7,7 +7,7 @@ if [ -x "$(command -v git)" ]
 then
    echo "SUCCESS: Git is installed"
 else
-    echo "WARNING: Git does not seem to be installed."
+    echo "ERROR: Git does not seem to be installed."
    echo "Please download Git using your package manager or over https://git-scm.com/!"
    exit 1
 fi
@@ -16,7 +16,7 @@ if [ -x "$(command -v rustc)" ]
 then
    echo "SUCCESS: Rust is installed"
 else
-    echo "WARNING: Rust does not seem to be installed."
+    echo "ERROR: Rust does not seem to be installed."
    echo "Please download Rust using https://rustup.rs!"
    exit 1
 fi
@@ -25,11 +25,27 @@ if [ -x "$(command -v cargo)" ]
 then
    echo "SUCCESS: Cargo is installed"
 else
-    echo "WARNING: Cargo does not seem to be installed."
+    echo "ERROR: Cargo does not seem to be installed."
    echo "Please download Rust and Cargo using https://rustup.rs!"
    exit 1
 fi

+# Look up python installations, starting with 3 with a fallback of 2
+if [ -x "$(command -v python3)" ]
+then
+    PY="$(command -v python3)"
+elif [ -x "$(command -v python)" ]
+then
+    PY="$(command -v python)"
+elif [ -x "$(command -v python2)" ]
+then
+    PY="$(command -v python2)"
+else
+    echo "ERROR: No working python installation was found"
+    echo "Please install python and add it to the PATH variable"
+    exit 1
+fi
+
 # Function that compares two versions strings v1 and v2 given in arguments (e.g 1.31 and 1.33.0).
 # Returns 1 if v1 > v2, 0 if v1 == v2, 2 if v1 < v2.
 function vercomp() {
@@ -75,7 +91,7 @@ MinRustVersion=1.31
 vercomp $RustVersion $MinRustVersion
 if [ $? -eq 2 ]
 then
-    echo "WARNING: Rust version is too old: $RustVersion - needs at least $MinRustVersion"
+    echo "ERROR: Rust version is too old: $RustVersion - needs at least $MinRustVersion"
    echo "Please update Rust with 'rustup update'"
    exit 1
 else
@@ -86,17 +102,46 @@ Path=${1:-rustlings/}
 echo "Cloning Rustlings at $Path..."
 git clone -q https://github.com/rust-lang/rustlings $Path

-Version=$(curl -s https://api.github.com/repos/rust-lang/rustlings/releases/latest | python -c "import json,sys;obj=json.load(sys.stdin);print(obj['tag_name']);")
-echo "Checking out version $Version..."
 cd $Path
-git checkout -q tags/$Version
+
+Version=$(curl -s https://api.github.com/repos/rust-lang/rustlings/releases/latest | ${PY} -c "import json,sys;obj=json.load(sys.stdin);print(obj['tag_name']);")
+CargoBin="${CARGO_HOME:-$HOME/.cargo}/bin"
+
+if [[ -z ${Version} ]]
+then
+    echo "The latest tag version could not be fetched remotely."
+    echo "Using the local git repository..."
+    Version=$(ls -tr .git/refs/tags/ | tail -1)
+    if [[ -z ${Version}  ]]
+    then
+        echo "No valid tag version found"
+        echo "Rustlings will be installed using the main branch"
+        Version="main"
+    else
+        Version="tags/${Version}"
+    fi
+else
+    Version="tags/${Version}"
+fi
+
+echo "Checking out version $Version..."
+git checkout -q ${Version}

 echo "Installing the 'rustlings' executable..."
 cargo install --force --path .

 if ! [ -x "$(command -v rustlings)" ]
 then
-    echo "WARNING: Please check that you have '~/.cargo/bin' in your PATH environment variable!"
+    echo "WARNING: Please check that you have '$CargoBin' in your PATH environment variable!"
+fi
+
+# Checking whether Clippy is installed.
+# Due to a bug in Cargo, this must be done with Rustup: https://github.com/rust-lang/rustup/issues/1514
+Clippy=$(rustup component list | grep "clippy" | grep "installed")
+if [ -z "$Clippy" ]
+then
+    echo "Installing the 'cargo-clippy' executable..."
+    rustup component add clippy
 fi

 echo "All done! Run 'rustlings' to get started."
--- a/src/exercise.rs
+++ b/src/exercise.rs
@@ -1,20 +1,32 @@
+use regex::Regex;
 use serde::Deserialize;
 use std::fmt::{self, Display, Formatter};
-use std::fs::remove_file;
+use std::fs::{self, remove_file, File};
+use std::io::Read;
 use std::path::PathBuf;
-use std::process::{self, Command, Output};
+use std::process::{self, Command};

 const RUSTC_COLOR_ARGS: &[&str] = &["--color", "always"];
+const I_AM_DONE_REGEX: &str = r"(?m)^\s*///?\s*I\s+AM\s+NOT\s+DONE";
+const CONTEXT: usize = 2;
+const CLIPPY_CARGO_TOML_PATH: &str = "./exercises/clippy/Cargo.toml";

+// Get a temporary file name that is hopefully unique to this process
+#[inline]
 fn temp_file() -> String {
    format!("./temp_{}", process::id())
 }

-#[derive(Deserialize)]
+// The mode of the exercise.
+#[derive(Deserialize, Copy, Clone)]
 #[serde(rename_all = "lowercase")]
 pub enum Mode {
+    // Indicates that the exercise should be compiled as a binary
    Compile,
+    // Indicates that the exercise should be compiled as a test harness
    Test,
+    // Indicates that the exercise should be linted with clippy
+    Clippy,
 }

 #[derive(Deserialize)]
@@ -22,15 +34,74 @@ pub struct ExerciseList {
    pub exercises: Vec<Exercise>,
 }

+// A representation of a rustlings exercise.
+// This is deserialized from the accompanying info.toml file
 #[derive(Deserialize)]
 pub struct Exercise {
+    // Name of the exercise
+    pub name: String,
+    // The path to the file containing the exercise's source code
    pub path: PathBuf,
+    // The mode of the exercise (Test, Compile, or Clippy)
    pub mode: Mode,
+    // The hint text associated with the exercise
+    pub hint: String,
+}
+
+// An enum to track of the state of an Exercise.
+// An Exercise can be either Done or Pending
+#[derive(PartialEq, Debug)]
+pub enum State {
+    // The state of the exercise once it's been completed
+    Done,
+    // The state of the exercise while it's not completed yet
+    Pending(Vec<ContextLine>),
+}
+
+// The context information of a pending exercise
+#[derive(PartialEq, Debug)]
+pub struct ContextLine {
+    // The source code that is still pending completion
+    pub line: String,
+    // The line number of the source code still pending completion
+    pub number: usize,
+    // Whether or not this is important
+    pub important: bool,
+}
+
+// The result of compiling an exercise
+pub struct CompiledExercise<'a> {
+    exercise: &'a Exercise,
+    _handle: FileHandle,
+}
+
+impl<'a> CompiledExercise<'a> {
+    // Run the compiled exercise
+    pub fn run(&self) -> Result<ExerciseOutput, ExerciseOutput> {
+        self.exercise.run()
+    }
+}
+
+// A representation of an already executed binary
+#[derive(Debug)]
+pub struct ExerciseOutput {
+    // The textual contents of the standard output of the binary
+    pub stdout: String,
+    // The textual contents of the standard error of the binary
+    pub stderr: String,
+}
+
+struct FileHandle;
+
+impl Drop for FileHandle {
+    fn drop(&mut self) {
+        clean();
+    }
 }

 impl Exercise {
-    pub fn compile(&self) -> Output {
-        match self.mode {
+    pub fn compile(&self) -> Result<CompiledExercise, ExerciseOutput> {
+        let cmd = match self.mode {
            Mode::Compile => Command::new("rustc")
                .args(&[self.path.to_str().unwrap(), "-o", &temp_file()])
                .args(RUSTC_COLOR_ARGS)
@@ -39,18 +110,121 @@ impl Exercise {
                .args(&["--test", self.path.to_str().unwrap(), "-o", &temp_file()])
                .args(RUSTC_COLOR_ARGS)
                .output(),
+            Mode::Clippy => {
+                let cargo_toml = format!(
+                    r#"[package]
+name = "{}"
+version = "0.0.1"
+edition = "2018"
+[[bin]]
+name = "{}"
+path = "{}.rs""#,
+                    self.name, self.name, self.name
+                );
+                fs::write(CLIPPY_CARGO_TOML_PATH, cargo_toml)
+                    .expect("Failed to write 📎 Clippy 📎 Cargo.toml file.");
+                // To support the ability to run the clipy exercises, build
+                // an executable, in addition to running clippy. With a
+                // compilation failure, this would silently fail. But we expect
+                // clippy to reflect the same failure while compiling later.
+                Command::new("rustc")
+                    .args(&[self.path.to_str().unwrap(), "-o", &temp_file()])
+                    .args(RUSTC_COLOR_ARGS)
+                    .output()
+                    .expect("Failed to compile!");
+                // Due to an issue with Clippy, a cargo clean is required to catch all lints.
+                // See https://github.com/rust-lang/rust-clippy/issues/2604
+                // This is already fixed on Clippy's master branch. See this issue to track merging into Cargo:
+                // https://github.com/rust-lang/rust-clippy/issues/3837
+                Command::new("cargo")
+                    .args(&["clean", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
+                    .args(RUSTC_COLOR_ARGS)
+                    .output()
+                    .expect("Failed to run 'cargo clean'");
+                Command::new("cargo")
+                    .args(&["clippy", "--manifest-path", CLIPPY_CARGO_TOML_PATH])
+                    .args(RUSTC_COLOR_ARGS)
+                    .args(&["--", "-D", "warnings"])
+                    .output()
+            }
+        }
+        .expect("Failed to run 'compile' command.");
+
+        if cmd.status.success() {
+            Ok(CompiledExercise {
+                exercise: &self,
+                _handle: FileHandle,
+            })
+        } else {
+            clean();
+            Err(ExerciseOutput {
+                stdout: String::from_utf8_lossy(&cmd.stdout).to_string(),
+                stderr: String::from_utf8_lossy(&cmd.stderr).to_string(),
+            })
        }
-        .expect("Failed to run 'compile' command.")
    }

-    pub fn run(&self) -> Output {
-        Command::new(&temp_file())
+    fn run(&self) -> Result<ExerciseOutput, ExerciseOutput> {
+        let arg = match self.mode {
+            Mode::Test => "--show-output",
+            _ => ""
+        };
+        let cmd = Command::new(&temp_file()).arg(arg)
            .output()
-            .expect("Failed to run 'run' command")
+            .expect("Failed to run 'run' command");
+
+        let output = ExerciseOutput {
+            stdout: String::from_utf8_lossy(&cmd.stdout).to_string(),
+            stderr: String::from_utf8_lossy(&cmd.stderr).to_string(),
+        };
+
+        if cmd.status.success() {
+            Ok(output)
+        } else {
+            Err(output)
+        }
    }

-    pub fn clean(&self) {
-        let _ignored = remove_file(&temp_file());
+    pub fn state(&self) -> State {
+        let mut source_file =
+            File::open(&self.path).expect("We were unable to open the exercise file!");
+
+        let source = {
+            let mut s = String::new();
+            source_file
+                .read_to_string(&mut s)
+                .expect("We were unable to read the exercise file!");
+            s
+        };
+
+        let re = Regex::new(I_AM_DONE_REGEX).unwrap();
+
+        if !re.is_match(&source) {
+            return State::Done;
+        }
+
+        let matched_line_index = source
+            .lines()
+            .enumerate()
+            .filter_map(|(i, line)| if re.is_match(line) { Some(i) } else { None })
+            .next()
+            .expect("This should not happen at all");
+
+        let min_line = ((matched_line_index as i32) - (CONTEXT as i32)).max(0) as usize;
+        let max_line = matched_line_index + CONTEXT;
+
+        let context = source
+            .lines()
+            .enumerate()
+            .filter(|&(i, _)| i >= min_line && i <= max_line)
+            .map(|(i, line)| ContextLine {
+                line: line.to_string(),
+                number: i + 1,
+                important: i == matched_line_index,
+            })
+            .collect();
+
+        State::Pending(context)
    }
 }

@@ -60,20 +234,92 @@ impl Display for Exercise {
    }
 }

+#[inline]
+fn clean() {
+    let _ignored = remove_file(&temp_file());
+}
+
 #[cfg(test)]
 mod test {
    use super::*;
-    use std::fs::File;
    use std::path::Path;

    #[test]
    fn test_clean() {
        File::create(&temp_file()).unwrap();
        let exercise = Exercise {
-            path: PathBuf::from("example.rs"),
-            mode: Mode::Test,
+            name: String::from("example"),
+            path: PathBuf::from("tests/fixture/state/pending_exercise.rs"),
+            mode: Mode::Compile,
+            hint: String::from(""),
        };
-        exercise.clean();
+        let compiled = exercise.compile().unwrap();
+        drop(compiled);
        assert!(!Path::new(&temp_file()).exists());
    }
+
+    #[test]
+    fn test_pending_state() {
+        let exercise = Exercise {
+            name: "pending_exercise".into(),
+            path: PathBuf::from("tests/fixture/state/pending_exercise.rs"),
+            mode: Mode::Compile,
+            hint: String::new(),
+        };
+
+        let state = exercise.state();
+        let expected = vec![
+            ContextLine {
+                line: "// fake_exercise".to_string(),
+                number: 1,
+                important: false,
+            },
+            ContextLine {
+                line: "".to_string(),
+                number: 2,
+                important: false,
+            },
+            ContextLine {
+                line: "// I AM NOT DONE".to_string(),
+                number: 3,
+                important: true,
+            },
+            ContextLine {
+                line: "".to_string(),
+                number: 4,
+                important: false,
+            },
+            ContextLine {
+                line: "fn main() {".to_string(),
+                number: 5,
+                important: false,
+            },
+        ];
+
+        assert_eq!(state, State::Pending(expected));
+    }
+
+    #[test]
+    fn test_finished_exercise() {
+        let exercise = Exercise {
+            name: "finished_exercise".into(),
+            path: PathBuf::from("tests/fixture/state/finished_exercise.rs"),
+            mode: Mode::Compile,
+            hint: String::new(),
+        };
+
+        assert_eq!(exercise.state(), State::Done);
+    }
+
+    #[test]
+    fn test_exercise_with_output() {
+        let exercise = Exercise {
+            name: "finished_exercise".into(),
+            path: PathBuf::from("tests/fixture/success/testSuccess.rs"),
+            mode: Mode::Test,
+            hint: String::new(),
+        };
+        let out = exercise.compile().unwrap().run().unwrap();
+        assert!(out.stdout.contains("THIS TEST TOO SHALL PASS"));
+    }
 }
--- a/src/main.rs
+++ b/src/main.rs
@@ -2,14 +2,22 @@ use crate::exercise::{Exercise, ExerciseList};
 use crate::run::run;
 use crate::verify::verify;
 use clap::{crate_version, App, Arg, SubCommand};
+use console::Emoji;
 use notify::DebouncedEvent;
 use notify::{RecommendedWatcher, RecursiveMode, Watcher};
 use std::ffi::OsStr;
 use std::fs;
+use std::io;
 use std::path::Path;
+use std::process::{Command, Stdio};
 use std::sync::mpsc::channel;
+use std::sync::{Arc, Mutex};
+use std::thread;
 use std::time::Duration;

+#[macro_use]
+mod ui;
+
 mod exercise;
 mod run;
 mod verify;
@@ -19,18 +27,36 @@ fn main() {
        .version(crate_version!())
        .author("Olivia Hugger, Carol Nichols")
        .about("Rustlings is a collection of small exercises to get you used to writing and reading Rust code")
-        .subcommand(SubCommand::with_name("verify").alias("v").about("Verifies all exercises according to the recommended order"))
-        .subcommand(SubCommand::with_name("watch").alias("w").about("Reruns `verify` when files were edited"))
+        .arg(
+            Arg::with_name("nocapture")
+                .long("nocapture")
+                .help("Show outputs from the test exercises")
+        )
+        .subcommand(
+            SubCommand::with_name("verify")
+                .alias("v")
+                .about("Verifies all exercises according to the recommended order")
+        )
+        .subcommand(
+            SubCommand::with_name("watch")
+                .alias("w")
+                .about("Reruns `verify` when files were edited")
+        )
        .subcommand(
            SubCommand::with_name("run")
                .alias("r")
                .about("Runs/Tests a single exercise")
-                .arg(Arg::with_name("file").required(true).index(1))
-                .arg(Arg::with_name("test").short("t").long("test").help("Run the file as a test")),
+                .arg(Arg::with_name("name").required(true).index(1)),
+        )
+        .subcommand(
+            SubCommand::with_name("hint")
+                .alias("h")
+                .about("Returns a hint for the current exercise")
+                .arg(Arg::with_name("name").required(true).index(1)),
        )
        .get_matches();

-    if None == matches.subcommand_name() {
+    if matches.subcommand_name().is_none() {
        println!();
        println!(r#"       welcome to...                      "#);
        println!(r#"                 _   _ _                  "#);
@@ -51,39 +77,62 @@ fn main() {
        std::process::exit(1);
    }

+    if !rustc_exists() {
+        println!("We cannot find `rustc`.");
+        println!("Try running `rustc --version` to diagnose your problem.");
+        println!("For instructions on how to install Rust, check the README.");
+        std::process::exit(1);
+    }
+
    let toml_str = &fs::read_to_string("info.toml").unwrap();
    let exercises = toml::from_str::<ExerciseList>(toml_str).unwrap().exercises;
+    let verbose = matches.is_present("nocapture");

    if let Some(ref matches) = matches.subcommand_matches("run") {
-        let filename = matches.value_of("file").unwrap_or_else(|| {
-            println!("Please supply a file name!");
-            std::process::exit(1);
-        });
+        let name = matches.value_of("name").unwrap();

-        let matching_exercise = |e: &&Exercise| {
-            Path::new(filename)
-                .canonicalize()
-                .map(|p| p.ends_with(&e.path))
-                .unwrap_or(false)
-        };
+        let matching_exercise = |e: &&Exercise| name == e.name;

        let exercise = exercises.iter().find(matching_exercise).unwrap_or_else(|| {
-            println!("No exercise found for your file name!");
+            println!("No exercise found for your given name!");
            std::process::exit(1)
        });

-        run(&exercise).unwrap_or_else(|_| std::process::exit(1));
+        run(&exercise, verbose).unwrap_or_else(|_| std::process::exit(1));
+    }
+
+    if let Some(ref matches) = matches.subcommand_matches("hint") {
+        let name = matches.value_of("name").unwrap();
+
+        let exercise = exercises
+            .iter()
+            .find(|e| name == e.name)
+            .unwrap_or_else(|| {
+                println!("No exercise found for your given name!");
+                std::process::exit(1)
+            });
+
+        println!("{}", exercise.hint);
    }

    if matches.subcommand_matches("verify").is_some() {
-        verify(&exercises).unwrap_or_else(|_| std::process::exit(1));
+        verify(&exercises, verbose).unwrap_or_else(|_| std::process::exit(1));
    }

-    if matches.subcommand_matches("watch").is_some() {
-        /* Clears the terminal with an ANSI escape code.
-           Works in UNIX and newer Windows terminals. */
-        println!("\x1Bc");
-        watch(&exercises).unwrap();
+    if matches.subcommand_matches("watch").is_some() && watch(&exercises, verbose).is_ok() {
+        println!(
+            "{emoji} All exercises completed! {emoji}",
+            emoji = Emoji("🎉", "★")
+        );
+        println!();
+        println!("We hope you enjoyed learning about the various aspects of Rust!");
+        println!(
+            "If you noticed any issues, please don't hesitate to report them to our repo."
+        );
+        println!("You can also contribute your own exercises to help the greater community!");
+        println!();
+        println!("Before reporting an issue or contributing, please read our guidelines:");
+        println!("https://github.com/rust-lang/rustlings/blob/main/CONTRIBUTING.md");
    }

    if matches.subcommand_name().is_none() {
@@ -92,25 +141,63 @@ fn main() {
    }
 }

-fn watch(exercises: &[Exercise]) -> notify::Result<()> {
+fn spawn_watch_shell(failed_exercise_hint: &Arc<Mutex<Option<String>>>) {
+    let failed_exercise_hint = Arc::clone(failed_exercise_hint);
+    println!("Type 'hint' to get help");
+    thread::spawn(move || loop {
+        let mut input = String::new();
+        match io::stdin().read_line(&mut input) {
+            Ok(_) => {
+                if input.trim().eq("hint") {
+                    if let Some(hint) = &*failed_exercise_hint.lock().unwrap() {
+                        println!("{}", hint);
+                    }
+                } else {
+                    println!("unknown command: {}", input);
+                }
+            }
+            Err(error) => println!("error reading command: {}", error),
+        }
+    });
+}
+
+fn watch(exercises: &[Exercise], verbose: bool) -> notify::Result<()> {
+    /* Clears the terminal with an ANSI escape code.
+    Works in UNIX and newer Windows terminals. */
+    fn clear_screen() {
+        println!("\x1Bc");
+    }
+
    let (tx, rx) = channel();

    let mut watcher: RecommendedWatcher = Watcher::new(tx, Duration::from_secs(2))?;
    watcher.watch(Path::new("./exercises"), RecursiveMode::Recursive)?;

-    let _ignored = verify(exercises.iter());
+    clear_screen();

+    let to_owned_hint = |t: &Exercise| t.hint.to_owned();
+    let failed_exercise_hint = match verify(exercises.iter(), verbose) {
+        Ok(_) => return Ok(()),
+        Err(exercise) => Arc::new(Mutex::new(Some(to_owned_hint(exercise)))),
+    };
+    spawn_watch_shell(&failed_exercise_hint);
    loop {
        match rx.recv() {
            Ok(event) => match event {
                DebouncedEvent::Create(b) | DebouncedEvent::Chmod(b) | DebouncedEvent::Write(b) => {
                    if b.extension() == Some(OsStr::new("rs")) && b.exists() {
-                        println!("----------**********----------\n");
                        let filepath = b.as_path().canonicalize().unwrap();
-                        let exercise = exercises
+                        let pending_exercises = exercises
                            .iter()
                            .skip_while(|e| !filepath.ends_with(&e.path));
-                        let _ignored = verify(exercise);
+                        clear_screen();
+                        match verify(pending_exercises, verbose) {
+                            Ok(_) => return Ok(()),
+                            Err(exercise) => {
+                                let mut failed_exercise_hint = failed_exercise_hint.lock().unwrap();
+                                *failed_exercise_hint = Some(to_owned_hint(exercise));
+                            }
+                        }
                    }
                }
                _ => {}
@@ -119,3 +206,13 @@ fn watch(exercises: &[Exercise]) -> notify::Result<()> {
        }
    }
 }
+
+fn rustc_exists() -> bool {
+    Command::new("rustc")
+        .args(&["--version"])
+        .stdout(Stdio::null())
+        .spawn()
+        .and_then(|mut child| child.wait())
+        .map(|status| status.success())
+        .unwrap_or(false)
+}
--- a/src/run.rs
+++ b/src/run.rs
@@ -1,52 +1,58 @@
 use crate::exercise::{Exercise, Mode};
 use crate::verify::test;
-use console::{style, Emoji};
 use indicatif::ProgressBar;

-pub fn run(exercise: &Exercise) -> Result<(), ()> {
+// Invoke the rust compiler on the path of the given exercise,
+// and run the ensuing binary.
+// The verbose argument helps determine whether or not to show
+// the output from the test harnesses (if the mode of the exercise is test)
+pub fn run(exercise: &Exercise, verbose: bool) -> Result<(), ()> {
    match exercise.mode {
-        Mode::Test => test(exercise)?,
+        Mode::Test => test(exercise, verbose)?,
        Mode::Compile => compile_and_run(exercise)?,
+        Mode::Clippy => compile_and_run(exercise)?,
    }
    Ok(())
 }

-pub fn compile_and_run(exercise: &Exercise) -> Result<(), ()> {
+// Invoke the rust compiler on the path of the given exercise
+// and run the ensuing binary.
+// This is strictly for non-test binaries, so output is displayed
+fn compile_and_run(exercise: &Exercise) -> Result<(), ()> {
    let progress_bar = ProgressBar::new_spinner();
    progress_bar.set_message(format!("Compiling {}...", exercise).as_str());
    progress_bar.enable_steady_tick(100);

-    let compilecmd = exercise.compile();
+    let compilation_result = exercise.compile();
+    let compilation = match compilation_result {
+        Ok(compilation) => compilation,
+        Err(output) => {
+            progress_bar.finish_and_clear();
+            warn!(
+                "Compilation of {} failed!, Compiler error message:\n",
+                exercise
+            );
+            println!("{}", output.stderr);
+            return Err(());
+        }
+    };
+
    progress_bar.set_message(format!("Running {}...", exercise).as_str());
-    if compilecmd.status.success() {
-        let runcmd = exercise.run();
-        progress_bar.finish_and_clear();
+    let result = compilation.run();
+    progress_bar.finish_and_clear();

-        if runcmd.status.success() {
-            println!("{}", String::from_utf8_lossy(&runcmd.stdout));
-            let formatstr = format!("{} Successfully ran {}", Emoji("✅", "✓"), exercise);
-            println!("{}", style(formatstr).green());
-            exercise.clean();
+    match result {
+        Ok(output) => {
+            println!("{}", output.stdout);
+            success!("Successfully ran {}", exercise);
            Ok(())
-        } else {
-            println!("{}", String::from_utf8_lossy(&runcmd.stdout));
-            println!("{}", String::from_utf8_lossy(&runcmd.stderr));
+        }
+        Err(output) => {
+            println!("{}", output.stdout);
+            println!("{}", output.stderr);

-            let formatstr = format!("{} Ran {} with errors", Emoji("⚠️ ", "!"), exercise);
-            println!("{}", style(formatstr).red());
-            exercise.clean();
+            warn!("Ran {} with errors", exercise);
            Err(())
        }
-    } else {
-        progress_bar.finish_and_clear();
-        let formatstr = format!(
-            "{} Compilation of {} failed! Compiler error message:\n",
-            Emoji("⚠️ ", "!"),
-            exercise
-        );
-        println!("{}", style(formatstr).red());
-        println!("{}", String::from_utf8_lossy(&compilecmd.stderr));
-        exercise.clean();
-        Err(())
    }
 }
--- a/src/ui.rs
+++ b/src/ui.rs
@@ -0,0 +1,23 @@
+macro_rules! warn {
+    ($fmt:literal, $ex:expr) => {{
+        use console::{style, Emoji};
+        let formatstr = format!($fmt, $ex);
+        println!(
+            "{} {}",
+            style(Emoji("⚠️ ", "!")).red(),
+            style(formatstr).red()
+        );
+    }};
+}
+
+macro_rules! success {
+    ($fmt:literal, $ex:expr) => {{
+        use console::{style, Emoji};
+        let formatstr = format!($fmt, $ex);
+        println!(
+            "{} {}",
+            style(Emoji("✅", "✓")).green(),
+            style(formatstr).green()
+        );
+    }};
+}
--- a/src/verify.rs
+++ b/src/verify.rs
@@ -1,79 +1,185 @@
-use crate::exercise::{Exercise, Mode};
-use console::{style, Emoji};
+use crate::exercise::{CompiledExercise, Exercise, Mode, State};
+use console::style;
 use indicatif::ProgressBar;

-pub fn verify<'a>(start_at: impl IntoIterator<Item = &'a Exercise>) -> Result<(), ()> {
+// Verify that the provided container of Exercise objects
+// can be compiled and run without any failures.
+// Any such failures will be reported to the end user.
+// If the Exercise being verified is a test, the verbose boolean
+// determines whether or not the test harness outputs are displayed.
+pub fn verify<'a>(
+    start_at: impl IntoIterator<Item = &'a Exercise>,
+    verbose: bool
+) -> Result<(), &'a Exercise> {
    for exercise in start_at {
-        match exercise.mode {
-            Mode::Test => test(&exercise)?,
-            Mode::Compile => compile_only(&exercise)?,
+        let compile_result = match exercise.mode {
+            Mode::Test => compile_and_test(&exercise, RunMode::Interactive, verbose),
+            Mode::Compile => compile_and_run_interactively(&exercise),
+            Mode::Clippy => compile_only(&exercise),
+        };
+        if !compile_result.unwrap_or(false) {
+            return Err(exercise);
        }
    }
    Ok(())
 }

-fn compile_only(exercise: &Exercise) -> Result<(), ()> {
+enum RunMode {
+    Interactive,
+    NonInteractive,
+}
+
+// Compile and run the resulting test harness of the given Exercise
+pub fn test(exercise: &Exercise, verbose: bool) -> Result<(), ()> {
+    compile_and_test(exercise, RunMode::NonInteractive, verbose)?;
+    Ok(())
+}
+
+// Invoke the rust compiler without running the resulting binary
+fn compile_only(exercise: &Exercise) -> Result<bool, ()> {
    let progress_bar = ProgressBar::new_spinner();
    progress_bar.set_message(format!("Compiling {}...", exercise).as_str());
    progress_bar.enable_steady_tick(100);
-    let compile_output = exercise.compile();
+
+    let _ = compile(&exercise, &progress_bar)?;
    progress_bar.finish_and_clear();
-    if compile_output.status.success() {
-        let formatstr = format!("{} Successfully compiled {}!", Emoji("✅", "✓"), exercise);
-        println!("{}", style(formatstr).green());
-        exercise.clean();
-        Ok(())
-    } else {
-        let formatstr = format!(
-            "{} Compilation of {} failed! Compiler error message:\n",
-            Emoji("⚠️ ", "!"),
-            exercise
-        );
-        println!("{}", style(formatstr).red());
-        println!("{}", String::from_utf8_lossy(&compile_output.stderr));
-        exercise.clean();
-        Err(())
-    }
+
+    success!("Successfully compiled {}!", exercise);
+    Ok(prompt_for_completion(&exercise, None))
 }

-pub fn test(exercise: &Exercise) -> Result<(), ()> {
+// Compile the given Exercise and run the resulting binary in an interactive mode
+fn compile_and_run_interactively(exercise: &Exercise) -> Result<bool, ()> {
+    let progress_bar = ProgressBar::new_spinner();
+    progress_bar.set_message(format!("Compiling {}...", exercise).as_str());
+    progress_bar.enable_steady_tick(100);
+
+    let compilation = compile(&exercise, &progress_bar)?;
+
+    progress_bar.set_message(format!("Running {}...", exercise).as_str());
+    let result = compilation.run();
+    progress_bar.finish_and_clear();
+
+    let output = match result {
+        Ok(output) => output,
+        Err(output) => {
+            warn!("Ran {} with errors", exercise);
+            println!("{}", output.stdout);
+            return Err(());
+        }
+    };
+
+    success!("Successfully ran {}!", exercise);
+
+    Ok(prompt_for_completion(&exercise, Some(output.stdout)))
+}
+
+// Compile the given Exercise as a test harness and display
+// the output if verbose is set to true
+fn compile_and_test(
+    exercise: &Exercise, run_mode: RunMode, verbose: bool
+) -> Result<bool, ()> {
    let progress_bar = ProgressBar::new_spinner();
    progress_bar.set_message(format!("Testing {}...", exercise).as_str());
    progress_bar.enable_steady_tick(100);

-    let compile_output = exercise.compile();
-    if compile_output.status.success() {
-        progress_bar.set_message(format!("Running {}...", exercise).as_str());
+    let compilation = compile(exercise, &progress_bar)?;
+    let result = compilation.run();
+    progress_bar.finish_and_clear();

-        let runcmd = exercise.run();
-        progress_bar.finish_and_clear();
-
-        if runcmd.status.success() {
-            let formatstr = format!("{} Successfully tested {}!", Emoji("✅", "✓"), exercise);
-            println!("{}", style(formatstr).green());
-            exercise.clean();
-            Ok(())
-        } else {
-            let formatstr = format!(
-                "{} Testing of {} failed! Please try again. Here's the output:",
-                Emoji("⚠️ ", "!"),
+    match result {
+        Ok(output) => {
+            if verbose {
+                println!("{}", output.stdout);
+            }
+            success!("Successfully tested {}", &exercise);
+            if let RunMode::Interactive = run_mode {
+                Ok(prompt_for_completion(&exercise, None))
+            } else {
+                Ok(true)
+            }
+        }
+        Err(output) => {
+            warn!(
+                "Testing of {} failed! Please try again. Here's the output:",
                exercise
            );
-            println!("{}", style(formatstr).red());
-            println!("{}", String::from_utf8_lossy(&runcmd.stdout));
-            exercise.clean();
+            println!("{}", output.stdout);
            Err(())
        }
-    } else {
-        progress_bar.finish_and_clear();
-        let formatstr = format!(
-            "{} Compiling of {} failed! Please try again. Here's the output:",
-            Emoji("⚠️ ", "!"),
-            exercise
-        );
-        println!("{}", style(formatstr).red());
-        println!("{}", String::from_utf8_lossy(&compile_output.stderr));
-        exercise.clean();
-        Err(())
    }
 }
+
+// Compile the given Exercise and return an object with information
+// about the state of the compilation
+fn compile<'a, 'b>(
+    exercise: &'a Exercise,
+    progress_bar: &'b ProgressBar,
+) -> Result<CompiledExercise<'a>, ()> {
+    let compilation_result = exercise.compile();
+
+    match compilation_result {
+        Ok(compilation) => Ok(compilation),
+        Err(output) => {
+            progress_bar.finish_and_clear();
+            warn!(
+                "Compiling of {} failed! Please try again. Here's the output:",
+                exercise
+            );
+            println!("{}", output.stderr);
+            Err(())
+        }
+    }
+}
+
+fn prompt_for_completion(exercise: &Exercise, prompt_output: Option<String>) -> bool {
+    let context = match exercise.state() {
+        State::Done => return true,
+        State::Pending(context) => context,
+    };
+
+    let success_msg = match exercise.mode {
+        Mode::Compile => "The code is compiling!",
+        Mode::Test => "The code is compiling, and the tests pass!",
+        Mode::Clippy => "The code is compiling, and 📎 Clippy 📎 is happy!",
+    };
+
+    println!();
+    println!("🎉 🎉  {} 🎉 🎉", success_msg);
+    println!();
+
+    if let Some(output) = prompt_output {
+        println!("Output:");
+        println!("{}", separator());
+        println!("{}", output);
+        println!("{}", separator());
+        println!();
+    }
+
+    println!("You can keep working on this exercise,");
+    println!(
+        "or jump into the next one by removing the {} comment:",
+        style("`I AM NOT DONE`").bold()
+    );
+    println!();
+    for context_line in context {
+        let formatted_line = if context_line.important {
+            format!("{}", style(context_line.line).bold())
+        } else {
+            context_line.line.to_string()
+        };
+
+        println!(
+            "{:>2} {}  {}",
+            style(context_line.number).blue().bold(),
+            style("|").blue(),
+            formatted_line
+        );
+    }
+
+    false
+}
+
+fn separator() -> console::StyledObject<&'static str> {
+    style("====================").bold()
+}
--- a/tests/fixture/failure/info.toml
+++ b/tests/fixture/failure/info.toml
@@ -1,7 +1,11 @@
 [[exercises]]
+name = "compFailure"
 path = "compFailure.rs"
 mode = "compile"
+hint = ""

 [[exercises]]
+name = "testFailure"
 path = "testFailure.rs"
-mode = "test"
+mode = "test"
+hint = "Hello!"
--- a/tests/fixture/state/finished_exercise.rs
+++ b/tests/fixture/state/finished_exercise.rs
@@ -0,0 +1,5 @@
+// fake_exercise
+
+fn main() {
+
+}
--- a/Show More
+++ b/Show More