Add elevator

elevator/.gitignore

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+/target

elevator/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "elevator"
+version = "0.1.0"

elevator/Cargo.toml

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+[package]
+name = "elevator"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

elevator/src/main.rs

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+#[derive(Debug)]
+/// An event in the elevator system that the controller must react to.
+enum Event {
+    Arrived(i32),
+    Called(i32, Direction),
+    Sent(i32),
+    DoorOpened,
+    DoorClosed,
+}
+
+/// A direction of travel.
+#[derive(Debug)]
+enum Direction {
+    Up,
+    Down,
+}
+
+/// The car has arrived on the given floor.
+fn car_arrived(floor: i32) -> Event {
+    Event::Arrived(floor)
+}
+
+/// The car doors have opened.
+fn car_door_opened() -> Event {
+    Event::DoorOpened
+}
+
+/// The car doors have closed.
+fn car_door_closed() -> Event {
+    Event::DoorClosed
+}
+
+/// A directional button was pressed in an elevator lobby on the given floor.
+fn lobby_call_button_pressed(floor: i32, dir: Direction) -> Event {
+    Event::Called(floor, dir)
+}
+
+/// A floor button was pressed in the elevator car.
+fn car_floor_button_pressed(floor: i32) -> Event {
+    Event::Sent(floor)
+}
+
+fn main() {
+    println!(
+        "A ground floor passenger has pressed the up button: {:?}",
+        lobby_call_button_pressed(0, Direction::Up)
+    );
+    println!(
+        "The car has arrived on the ground floor: {:?}",
+        car_arrived(0)
+    );
+    println!("The car door opened: {:?}", car_door_opened());
+    println!(
+        "A passenger has pressed the 3rd floor button: {:?}",
+        car_floor_button_pressed(3)
+    );
+    println!("The car door closed: {:?}", car_door_closed());
+    println!("The car has arrived on the 3rd floor: {:?}", car_arrived(3));
+}