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Derive PartialEq/Eq for vga buffer types

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Philipp Oppermann
2018-04-25 19:59:38 +02:00
parent 44ffa1d046
commit 573e1ed40c
1 changed files with 6 additions and 4 deletions
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10
blog/content/second-edition/posts/03-vga-text-buffer/index.md
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@@ -68,7 +68,7 @@ First, we represent the different colors using an enum:
```rust ```rust
#[allow(dead_code)] #[allow(dead_code)]
#[derive(Debug, Clone, Copy)] #[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(u8)] #[repr(u8)]
pub enum Color { pub enum Color {
Black = 0, Black = 0,
@@ -95,12 +95,14 @@ We use a [C-like enum] here to explicitly specify the number for each color. Bec
Normally the compiler would issue a warning for each unused variant. By using the `#[allow(dead_code)]` attribute we disable these warnings for the `Color` enum. Normally the compiler would issue a warning for each unused variant. By using the `#[allow(dead_code)]` attribute we disable these warnings for the `Color` enum.
By [deriving] the [`Copy`], [`Clone`] and [`Debug`] traits, we enable [copy semantics] for the type and make it printable. By [deriving] the [`Copy`], [`Clone`], [`Debug`], [`PartialEq`], and [`Eq`] traits, we enable [copy semantics] for the type and make it printable and comparable.
[deriving]: http://rustbyexample.com/trait/derive.html [deriving]: http://rustbyexample.com/trait/derive.html
[`Copy`]: https://doc.rust-lang.org/nightly/core/marker/trait.Copy.html [`Copy`]: https://doc.rust-lang.org/nightly/core/marker/trait.Copy.html
[`Clone`]: https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html [`Clone`]: https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html
[`Debug`]: https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html [`Debug`]: https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html
[`PartialEq`]: https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html
[`Eq`]: https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html
[copy semantics]: https://doc.rust-lang.org/book/first-edition/ownership.html#copy-types [copy semantics]: https://doc.rust-lang.org/book/first-edition/ownership.html#copy-types
To represent a full color code that specifies foreground and background color, we create a [newtype] on top of `u8`: To represent a full color code that specifies foreground and background color, we create a [newtype] on top of `u8`:
@@ -108,7 +110,7 @@ To represent a full color code that specifies foreground and background color, w
[newtype]: https://rustbyexample.com/generics/new_types.html [newtype]: https://rustbyexample.com/generics/new_types.html
```rust ```rust
#[derive(Debug, Clone, Copy)] #[derive(Debug, Clone, Copy, PartialEq, Eq)]
struct ColorCode(u8); struct ColorCode(u8);
impl ColorCode { impl ColorCode {
@@ -130,7 +132,7 @@ The `ColorCode` contains the full color byte, containing foreground and backgrou
Now we can add structures to represent a screen character and the text buffer: Now we can add structures to represent a screen character and the text buffer:
```rust ```rust
#[derive(Debug, Clone, Copy)] #[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(C)] #[repr(C)]
struct ScreenChar { struct ScreenChar {
ascii_character: u8, ascii_character: u8,