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-rw-r--r--exercises/08_enums/README.md10
-rw-r--r--exercises/08_enums/enums1.rs17
-rw-r--r--exercises/08_enums/enums2.rs30
-rw-r--r--exercises/08_enums/enums3.rs73
4 files changed, 130 insertions, 0 deletions
diff --git a/exercises/08_enums/README.md b/exercises/08_enums/README.md
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+# Enums
+
+Rust allows you to define types called "enums" which enumerate possible values.
+Enums are a feature in many languages, but their capabilities differ in each language. Rust’s enums are most similar to algebraic data types in functional languages, such as F#, OCaml, and Haskell.
+Useful in combination with enums is Rust's "pattern matching" facility, which makes it easy to run different code for different values of an enumeration.
+
+## Further information
+
+- [Enums](https://doc.rust-lang.org/book/ch06-00-enums.html)
+- [Pattern syntax](https://doc.rust-lang.org/book/ch18-03-pattern-syntax.html)
diff --git a/exercises/08_enums/enums1.rs b/exercises/08_enums/enums1.rs
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+// enums1.rs
+//
+// No hints this time! ;)
+
+// I AM NOT DONE
+
+#[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);
+}
diff --git a/exercises/08_enums/enums2.rs b/exercises/08_enums/enums2.rs
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+// enums2.rs
+//
+// Execute `rustlings hint enums2` or use the `hint` watch subcommand for a
+// hint.
+
+// I AM NOT DONE
+
+#[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();
+ }
+}
diff --git a/exercises/08_enums/enums3.rs b/exercises/08_enums/enums3.rs
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+// 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
+
+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,
+ message: String,
+}
+
+impl State {
+ fn change_color(&mut self, color: (u8, u8, u8)) {
+ self.color = color;
+ }
+
+ fn quit(&mut self) {
+ self.quit = true;
+ }
+
+ fn echo(&mut self, s: String) {
+ self.message = 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
+ // Remember: When passing a tuple as a function argument, you'll need extra parentheses:
+ // fn function((t, u, p, l, e))
+ }
+}
+
+#[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),
+ message: "hello world".to_string(),
+ };
+ state.process(Message::ChangeColor(255, 0, 255));
+ state.process(Message::Echo(String::from("Hello world!")));
+ state.process(Message::Move(Point { x: 10, y: 15 }));
+ state.process(Message::Quit);
+
+ assert_eq!(state.color, (255, 0, 255));
+ assert_eq!(state.position.x, 10);
+ assert_eq!(state.position.y, 15);
+ assert_eq!(state.quit, true);
+ assert_eq!(state.message, "Hello world!");
+ }
+}