Merge branch '5.0-dev'

.github/workflows/rust.yml

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

.gitignore

@@ -9,3 +9,4 @@ rust-project.json
 .idea
 .vscode
 *.iml
+*.o

CONTRIBUTING.md

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

Cargo.lock

@@ -459,7 +459,7 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 
 [[package]]
 name = "rustlings"
-version = "4.7.1"
+version = "4.8.0"
 dependencies = [
  "argh",
  "assert_cmd",

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "rustlings"
 version = "4.8.0"
-authors = ["mokou <mokou@fastmail.com>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
+authors = ["Liv <mokou@fastmail.com>", "Carol (Nichols || Goulding) <carol.nichols@gmail.com>"]
 edition = "2021"
 
 [dependencies]
@@ -24,6 +24,3 @@ path = "src/main.rs"
 assert_cmd = "0.11.0"
 predicates = "1.0.1"
 glob = "0.3.0"
-
-[features]
-exercises = []

README.md

@@ -44,9 +44,9 @@ Start-BitsTransfer -Source https://raw.githubusercontent.com/rust-lang/rustlings
 
 To install Rustlings. Same as on MacOS/Linux, you will have access to the `rustlings` command after it.
 
-When you get a permission denied message then you have to exclude the directory where you placed the rustlings in your virus-scanner
+If you get a permission denied message, you might have to exclude the directory where you cloned Rustlings in your antivirus.
 
-## Browser:
+## Browser
 
 [Run on Repl.it](https://repl.it/github/rust-lang/rustlings)
 
@@ -150,24 +150,6 @@ cargo uninstall rustlings
 
 Now you should be done!
 
-## Completion
-
-Rustlings isn't done; there are a couple of sections that are very experimental and don't have proper documentation. These include:
-
-- Errors (`exercises/errors/`)
-- Option (`exercises/option/`)
-- Result (`exercises/result/`)
-- Move Semantics (could still be improved, `exercises/move_semantics/`)
-
-Additionally, we could use exercises on a couple of topics:
-
-- Structs
-- Better ownership stuff
-- `impl`
-- ??? probably more
-
-If you are interested in improving or adding new ones, please feel free to contribute! Read on for more information :)
-
 ## Contributing
 
 See [CONTRIBUTING.md](./CONTRIBUTING.md).

exercises/advanced_errors/advanced_errs1.rs

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

exercises/advanced_errors/advanced_errs2.rs

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

exercises/advanced_errors/mod.rs

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

exercises/clippy/clippy1.rs

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

exercises/clippy/clippy2.rs

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

exercises/clippy/clippy3.rs

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

exercises/clippy/mod.rs

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

exercises/collections/README.md

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

exercises/collections/mod.rs

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

exercises/conversions/as_ref_mut.rs

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

exercises/conversions/from_into.rs

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

exercises/conversions/from_str.rs

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

exercises/conversions/mod.rs

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

exercises/conversions/try_from_into.rs

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

exercises/conversions/using_as.rs

@@ -4,6 +4,7 @@
 //
 // The goal is to make sure that the division does not fail to compile
 // and returns the proper type.
+// Execute `rustlings hint using_as` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/enums/enums1.rs

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

exercises/enums/enums2.rs

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

exercises/enums/enums3.rs

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

exercises/enums/mod.rs

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

exercises/error_handling/errors1.rs

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

exercises/error_handling/errors2.rs

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

exercises/error_handling/errors3.rs

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

exercises/error_handling/errors4.rs

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

exercises/error_handling/errors5.rs

@@ -1,8 +1,18 @@
 // errors5.rs
 
-// This program uses a completed version of the code from errors4.
+// This program uses an altered version of the code from errors4.
-// It won't compile right now! Why?
+
-// Execute `rustlings hint errors5` for hints!
+// This exercise uses some concepts that we won't get to until later in the course, like `Box` and the
+// `From` trait. It's not important to understand them in detail right now, but you can read ahead if you like.
+
+// In short, this particular use case for boxes is for when you want to own a value and you care only that it is a 
+// type which implements a particular trait. To do so, The Box is declared as of type Box<dyn Trait> where Trait is the trait
+// the compiler looks for on any value used in that context. For this exercise, that context is the potential errors
+// which can be returned in a Result.
+
+// What can we use to describe both errors? In other words, is there a trait which both errors implement?
+
+// Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -11,7 +21,7 @@ use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), ParseIntError> {
+fn main() -> Result<(), Box<dyn ???>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);

exercises/error_handling/errors6.rs

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

exercises/error_handling/mod.rs

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

exercises/functions/README.md

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

exercises/functions/functions1.rs

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

exercises/functions/functions2.rs

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

exercises/functions/functions3.rs

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

exercises/functions/functions4.rs

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

exercises/functions/functions5.rs

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

exercises/functions/mod.rs

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

exercises/generics/generics1.rs

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

exercises/generics/generics2.rs

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

exercises/generics/generics3.rs

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

exercises/generics/mod.rs

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

exercises/hashmaps/README.md

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

exercises/hashmaps/hashmaps1.rs

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

exercises/hashmaps/hashmaps2.rs

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

exercises/hashmaps/hashmaps3.rs

@@ -0,0 +1,87 @@
+// hashmaps3.rs
+
+// A list of scores (one per line) of a soccer match is given. Each line
+// is of the form :
+// <team_1_name>,<team_2_name>,<team_1_goals>,<team_2_goals>
+// Example: England,France,4,2 (England scored 4 goals, France 2).
+
+// You have to build a scores table containing the name of the team, goals
+// the team scored, and goals the team conceded. One approach to build
+// the scores table is to use a Hashmap. The solution is partially
+// written to use a Hashmap, complete it to pass the test.
+
+// Make me pass the tests!
+
+// Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+use std::collections::HashMap;
+
+// A structure to store team name and its goal details.
+struct Team {
+    name: String,
+    goals_scored: u8,
+    goals_conceded: u8,
+}
+
+fn build_scores_table(results: String) -> HashMap<String, Team> {
+    // The name of the team is the key and its associated struct is the value.
+    let mut scores: HashMap<String, Team> = HashMap::new();
+
+    for r in results.lines() {
+        let v: Vec<&str> = r.split(',').collect();
+        let team_1_name = v[0].to_string();
+        let team_1_score: u8 = v[2].parse().unwrap();
+        let team_2_name = v[1].to_string();
+        let team_2_score: u8 = v[3].parse().unwrap();
+        // TODO: Populate the scores table with details extracted from the
+        // current line. Keep in mind that goals scored by team_1
+        // will be number of goals conceded from team_2, and similarly
+        // goals scored by team_2 will be the number of goals conceded by
+        // team_1.
+    }
+    scores
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn get_results() -> String {
+        let results = "".to_string()
+            + "England,France,4,2\n"
+            + "France,Italy,3,1\n"
+            + "Poland,Spain,2,0\n"
+            + "Germany,England,2,1\n";
+        results
+    }
+
+    #[test]
+    fn build_scores() {
+        let scores = build_scores_table(get_results());
+
+        let mut keys: Vec<&String> = scores.keys().collect();
+        keys.sort();
+        assert_eq!(
+            keys,
+            vec!["England", "France", "Germany", "Italy", "Poland", "Spain"]
+        );
+    }
+
+    #[test]
+    fn validate_team_score_1() {
+        let scores = build_scores_table(get_results());
+        let team = scores.get("England").unwrap();
+        assert_eq!(team.goals_scored, 5);
+        assert_eq!(team.goals_conceded, 4);
+    }
+
+    #[test]
+    fn validate_team_score_2() {
+        let scores = build_scores_table(get_results());
+        let team = scores.get("Spain").unwrap();
+        assert_eq!(team.goals_scored, 0);
+        assert_eq!(team.goals_conceded, 2);
+    }
+}

exercises/if/README.md

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

exercises/if/if1.rs

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

exercises/if/if2.rs

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

exercises/if/mod.rs

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

exercises/intro/intro1.rs

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

exercises/intro/intro2.rs

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

exercises/intro/mod.rs

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

exercises/lifetimes/README.md

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

exercises/lifetimes/lifetimes1.rs

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

exercises/lifetimes/lifetimes2.rs

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

exercises/lifetimes/lifetimes3.rs

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

exercises/macros/macros1.rs

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

exercises/macros/macros2.rs

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

exercises/macros/macros3.rs

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

exercises/macros/macros4.rs

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

exercises/macros/mod.rs

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

exercises/mod.rs

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

exercises/modules/mod.rs

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

exercises/modules/modules1.rs

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

exercises/modules/modules2.rs

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

exercises/modules/modules3.rs

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

exercises/move_semantics/mod.rs

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

exercises/move_semantics/move_semantics1.rs

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

exercises/move_semantics/move_semantics2.rs

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

exercises/move_semantics/move_semantics3.rs

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

exercises/move_semantics/move_semantics4.rs

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

exercises/move_semantics/move_semantics5.rs

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

exercises/move_semantics/move_semantics6.rs

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

exercises/option/mod.rs

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

exercises/option/option1.rs

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

exercises/options/README.md

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

exercises/options/options1.rs

@@ -0,0 +1,37 @@
+// options1.rs
+// Execute `rustlings hint options1` or use the `hint` watch subcommand for a hint.
+
+// I AM NOT DONE
+
+// you can modify anything EXCEPT for this function's signature
+fn print_number(maybe_number: Option<u16>) {
+    println!("printing: {}", maybe_number.unwrap());
+}
+
+// This function returns how much icecream there is left in the fridge.
+// If it's before 10PM, there's 5 pieces left. At 10PM, someone eats them
+// all, so there'll be no more left :(
+// TODO: Return an Option!
+fn maybe_icecream(time_of_day: u16) -> Option<u16> {
+    // We use the 24-hour system here, so 10PM is a value of 22
+    ???
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn check_icecream() {
+        assert_eq!(maybe_icecream(10), Some(5));
+        assert_eq!(maybe_icecream(23), None);
+        assert_eq!(maybe_icecream(22), None);
+    }
+
+    #[test]
+    fn raw_value() {
+        // TODO: Fix this test. How do you get at the value contained in the Option?
+        let icecreams = maybe_icecream(12);
+        assert_eq!(icecreams, 5);
+    }
+}

exercises/options/options2.rs

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

exercises/options/options3.rs

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

exercises/primitive_types/mod.rs

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

exercises/primitive_types/primitive_types2.rs

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

exercises/primitive_types/primitive_types3.rs

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

exercises/primitive_types/primitive_types4.rs

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

exercises/primitive_types/primitive_types5.rs

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

exercises/primitive_types/primitive_types6.rs

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

exercises/quiz1.rs

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

exercises/quiz2.rs

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

exercises/quiz3.rs

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

exercises/quiz4.rs

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

exercises/standard_library_types/arc1.rs

@@ -16,7 +16,7 @@
 // Make this code compile by filling in a value for `shared_numbers` where the
 // first TODO comment is, and create an initial binding for `child_numbers`
 // where the second TODO comment is. Try not to create any copies of the `numbers` Vec!
-// Execute `rustlings hint arc1` for hints :)
+// Execute `rustlings hint arc1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/standard_library_types/box1.rs

@@ -14,7 +14,7 @@
 //
 // Note: the tests should not be changed
 //
-// Execute `rustlings hint box1` for hints :)
+// Execute `rustlings hint box1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/standard_library_types/iterators1.rs

@@ -6,7 +6,7 @@
 // This module helps you get familiar with the structure of using an iterator and
 // how to go through elements within an iterable collection.
 //
-// Execute `rustlings hint iterators1` for hints :D
+// Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/standard_library_types/iterators2.rs

@@ -1,7 +1,7 @@
 // iterators2.rs
 // In this exercise, you'll learn some of the unique advantages that iterators
 // can offer. Follow the steps to complete the exercise.
-// As always, there are hints if you execute `rustlings hint iterators2`!
+// Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/standard_library_types/iterators3.rs

@@ -4,7 +4,7 @@
 // 1. Complete the divide function to get the first four tests to pass.
 // 2. Get the remaining tests to pass by completing the result_with_list and
 //    list_of_results functions.
-// Execute `rustlings hint iterators3` to get some hints!
+// Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -22,7 +22,9 @@ pub struct NotDivisibleError {
 
 // Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
-pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {}
+pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
+    todo!();
+}
 
 // Complete the function and return a value of the correct type so the test passes.
 // Desired output: Ok([1, 11, 1426, 3])

exercises/standard_library_types/iterators4.rs

@@ -1,4 +1,5 @@
 // iterators4.rs
+// Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 
@@ -18,6 +19,11 @@ pub fn factorial(num: u64) -> u64 {
 mod tests {
     use super::*;
 
+    #[test]
+    fn factorial_of_0() {
+        assert_eq!(1, factorial(0));
+    }
+
     #[test]
     fn factorial_of_1() {
         assert_eq!(1, factorial(1));

exercises/standard_library_types/iterators5.rs

@@ -6,7 +6,7 @@
 // imperative style for loops. Recreate this counting functionality using
 // iterators. Only the two iterator methods (count_iterator and
 // count_collection_iterator) need to be modified.
-// Execute `rustlings hint iterators5` for hints.
+// Execute `rustlings hint iterators5` or use the `hint` watch subcommand for a hint.
 //
 // Make the code compile and the tests pass.
 
@@ -34,6 +34,7 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
 fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
     // map is a hashmap with String keys and Progress values.
     // map = { "variables1": Complete, "from_str": None, ... }
+    todo!();
 }
 
 fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
@@ -52,6 +53,7 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
     // collection is a slice of hashmaps.
     // collection = [{ "variables1": Complete, "from_str": None, ... },
     //     { "variables2": Complete, ... }, ... ]
+    todo!();
 }
 
 #[cfg(test)]

exercises/standard_library_types/mod.rs

@@ -1,7 +0,0 @@
-mod arc1;
-mod box1;
-mod iterators1;
-mod iterators2;
-mod iterators3;
-mod iterators4;
-mod iterators5;

exercises/strings/mod.rs

@@ -1,2 +0,0 @@
-mod strings1;
-mod strings2;