Comprehensive Rust v2 (#1073)

I've taken some work by @fw-immunant and others on the new organization
of the course and condensed it into a form amenable to a text editor and
some computational analysis. You can see the inputs in `course.py` but
the interesting bits are the output: `outline.md` and `slides.md`.

The idea is to break the course into more, smaller segments with
exercises at the ends and breaks in between. So `outline.md` lists the
segments, their duration, and sums those durations up per-day. It shows
we're about an hour too long right now! There are more details of the
segments in `slides.md`, or you can see mostly the same stuff in
`course.py`.

This now contains all of the content from the v1 course, ensuring both
that we've covered everything and that we'll have somewhere to redirect
every page.

Fixes #1082.
Fixes #1465.

---------

Co-authored-by: Nicole LeGare <dlegare.1001@gmail.com>
Co-authored-by: Martin Geisler <mgeisler@google.com>

src/user-defined-types/exercise.rs

@@ -0,0 +1,107 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![allow(dead_code)]
+
+// ANCHOR: solution
+#[derive(Debug)]
+/// An event in the elevator system that the controller must react to.
+enum Event {
+    /// A button was pressed.
+    ButtonPressed(Button),
+
+    /// The car has arrived at the given floor.
+    CarArrived(Floor),
+
+    /// The car's doors have opened.
+    CarDoorOpened,
+
+    /// The car's doors have closed.
+    CarDoorClosed,
+}
+
+/// A floor is represented as an integer.
+type Floor = i32;
+
+/// A direction of travel.
+#[derive(Debug)]
+enum Direction {
+    Up,
+    Down,
+}
+
+/// A user-accessible button.
+#[derive(Debug)]
+enum Button {
+    /// A button in the elevator lobby on the given floor.
+    LobbyCall(Direction, Floor),
+
+    /// A floor button within the car.
+    CarFloor(Floor),
+}
+
+// ANCHOR: car_arrived
+/// The car has arrived on the given floor.
+fn car_arrived(floor: i32) -> Event {
+    // END_ANCHOR: car_arrived
+    Event::CarArrived(floor)
+}
+
+// ANCHOR: car_door_opened
+/// The car doors have opened.
+fn car_door_opened() -> Event {
+    // END_ANCHOR: car_door_opened
+    Event::CarDoorOpened
+}
+
+// ANCHOR: car_door_closed
+/// The car doors have closed.
+fn car_door_closed() -> Event {
+    // END_ANCHOR: car_door_closed
+    Event::CarDoorClosed
+}
+
+// ANCHOR: lobby_call_button_pressed
+/// A directional button was pressed in an elevator lobby on the given floor.
+fn lobby_call_button_pressed(floor: i32, dir: Direction) -> Event {
+    // END_ANCHOR: lobby_call_button_pressed
+    Event::ButtonPressed(Button::LobbyCall(dir, floor))
+}
+
+// ANCHOR: car_floor_button_pressed
+/// A floor button was pressed in the elevator car.
+fn car_floor_button_pressed(floor: i32) -> Event {
+    // END_ANCHOR: car_floor_button_pressed
+    Event::ButtonPressed(Button::CarFloor(floor))
+}
+
+// ANCHOR: main
+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));
+}
+// ANCHOR_END: main