diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/doc/book/redirects/trait-objects.md | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/doc/book/redirects/trait-objects.md')
-rw-r--r-- | src/doc/book/redirects/trait-objects.md | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/src/doc/book/redirects/trait-objects.md b/src/doc/book/redirects/trait-objects.md new file mode 100644 index 000000000..3200e26a1 --- /dev/null +++ b/src/doc/book/redirects/trait-objects.md @@ -0,0 +1,68 @@ +% Trait Objects + +<small>There is a new edition of the book and this is an old link.</small> + +> Trait objects combine the data made up of the pointer to a concrete object with the behavior of the methods defined in the trait. +> A trait defines behavior that we need in a given situation. +> We can then use a trait as a trait object in places where we would use a concrete type or a generic type. + +```rust,ignore +pub struct InputBox { + pub label: String, +} + +impl Draw for InputBox { + fn draw(&self) { + // Code to actually draw an input box + } +} + +pub struct Button { + pub label: String, +} + +impl Draw for Button { + fn draw(&self) { + // Code to actually draw a button + } +} + +pub struct Screen<T: Draw> { + pub components: Vec<T>, +} + +impl<T> Screen<T> + where T: Draw { + pub fn run(&self) { + for component in self.components.iter() { + component.draw(); + } + } +} + +fn main() { + let screen = Screen { + components: vec![ + Box::new(InputBox { + label: String::from("OK"), + }), + Box::new(Button { + label: String::from("OK"), + }), + ], + }; + + screen.run(); +} +``` + +--- + +Here are the relevant sections in the new and old books: + +* **[in the current edition: Ch 17.02 — Trait Objects][2]** +* <small>[In the first edition: Ch 3.22 — Trait Objects][1]</small> + + +[1]: https://doc.rust-lang.org/1.30.0/book/first-edition/trait-objects.html +[2]: ch17-02-trait-objects.html |