Merge pull request #154 from fbornhofen/speaker-notes

Speaker notes for box.md, rc.md, option-result.md

src/std/box.md

@@ -28,3 +28,10 @@ from `T` directly on a `Box<T>`][2].
 
 [1]: https://doc.rust-lang.org/std/boxed/struct.Box.html
 [2]: https://doc.rust-lang.org/std/ops/trait.Deref.html#more-on-deref-coercion
+
+<details>
+
+* `Box` is like `std::unique_ptr` in C++.
+* In the above example, you can even leave out the `*` in the `println!` statement thanks to `Deref`.
+
+</details>

src/std/option-result.md

@@ -12,3 +12,14 @@ fn main() {
     println!("idx: {idx:?}");
 }
 ```
+
+<details>
+
+* `Option` and `Result` are widely used not just in the standard library.
+* `Option<&T>` has zero space overhead compared to `&T`.
+* `Result` is the standard type to implement error handling as we will see on Day 3.
+* `binary_search` returns `Result<usize, usize>`.
+  * If found, `Result::Ok` holds the index where the element is found.
+  * Otherwise, `Result::Err` contains the index where such an element should be inserted.
+
+</details>

src/std/rc.md

@@ -22,3 +22,11 @@ context.
 [1]: https://doc.rust-lang.org/std/rc/struct.Rc.html
 [2]: https://doc.rust-lang.org/std/cell/index.html
 [3]: ../concurrency/shared_state/arc.md
+
+<details>
+
+* Like C++'s `std::shared_ptr`.
+* `clone` is cheap: creates a pointer to the same allocation and increases the reference count.
+* `make_mut` actually clones the inner value if necessary ("clone-on-write") and returns a mutable reference.
+
+</details>