feat: Add enums exercises

This commit is contained in:
Thomas Holloway 2019-10-28 22:49:49 -05:00
parent 2191ef7eee
commit dc15032112
5 changed files with 187 additions and 0 deletions

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### 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.
#### Book Sections
- [Enums](https://doc.rust-lang.org/book/ch06-00-enums.html)

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exercises/enums/enums1.rs Normal file
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// enums1.rs
// Make me compile! Scroll down for hints!
#[derive(Debug)]
enum Message {
// TODO: define a few types of messages as used below
}
fn main() {
println!("{:?}", Message::Quit);
println!("{:?}", Message::Echo);
println!("{:?}", Message::Move);
println!("{:?}", Message::ChangeColor);
}
// Hint: The declaration of the enumeration type has not been defined yet.

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exercises/enums/enums2.rs Normal file
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// enums2.rs
// Make me compile! Scroll down for hints
#[derive(Debug)]
enum Message {
// TODO: define the different variants used below
}
impl Message {
fn call(&self) {
println!("{:?}", &self);
}
}
fn main() {
let messages = [
Message::Move{ x: 10, y: 30 },
Message::Echo(String::from("hello world")),
Message::ChangeColor(200, 255, 255),
Message::Quit
];
for message in &messages {
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

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exercises/enums/enums3.rs Normal file
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// enums3.rs
// Address all the TODOs to make the tests pass!
enum Message {
// TODO: implement the message variant types based on their usage below
}
struct Point {
x: u8,
y: u8
}
struct State {
color: (u8, u8, u8),
position: Point,
quit: bool
}
impl State {
fn change_color(&mut self, color: (u8, u8, u8)) {
self.color = color;
}
fn quit(&mut self) {
self.quit = true;
}
fn echo(&self, s: String) {
println!("{}", s);
}
fn move_position(&mut self, p: Point) {
self.position = p;
}
fn process(&mut self, message: Message) {
// TODO: create a match expression to process the different message variants
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_match_message_call() {
let mut state = State{
quit: false,
position: Point{ x: 0, y: 0 },
color: (0, 0, 0)
};
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::Quit);
assert_eq!(state.color, (255, 0, 255));
assert_eq!(state.position.x, 10);
assert_eq!(state.position.y, 15);
assert_eq!(state.quit, true);
}
}

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path = "exercises/structs/structs2.rs"
mode = "test"
# ENUMS
[[exercises]]
path = "exercises/enums/enums1.rs"
mode = "compile"
[[exercises]]
path = "exercises/enums/enums2.rs"
mode = "compile"
[[exercises]]
path = "exercises/enums/enums3.rs"
mode = "test"
# TESTS
[[exercises]]