use keyseq::{Modifiers, winit::lkey};
use winit::keyboard::Key;

assert_eq!(lkey! { a },          (Modifiers::NONE,    Key::Character('a')));
assert_eq!(lkey! { ctrl-a },     (Modifiers::CONTROL, Key::Character('a')));
assert_eq!(lkey! { alt-a },      (Modifiers::ALT,     Key::Character('a')));
assert_eq!(lkey! { shift-a },    (Modifiers::SHIFT,   Key::Character('a')));
assert_eq!(lkey! { super-a },    (Modifiers::SUPER,   Key::Character('a')));
assert_eq!(lkey! { ctrl-alt-; }, (Modifiers::ALT |
                                  Modifiers::CONTROL, Key::Character(';')));

逻辑按键序列

# use keyseq::Modifiers;
# use winit::keyboard::Key;
use keyseq::winit::lkeyseq;
assert_eq!(lkeyseq! { a ctrl-b }, [(Modifiers::NONE,    Key::Character('a')),
                                   (Modifiers::CONTROL, Key::Character('b'))]);

没有小写物理按键

以下代码将无法编译。它坚持使用大写 'A' 来指定 A 键。

# use keyseq::winit::pkey;
let (mods, key) = pkey! { a }; // error: Use uppercase key names for physical keys

严格的修饰符顺序

默认启用 "strict-order" 功能，修饰符顺序错误将产生编译错误。如果没有该功能，它将发出警告。

# use keyseq::winit::pkey;
let _ = pkey! { alt-ctrl-A }; // error: Modifiers must occur in this order: control, alt, shift, super.

为什么不使用 winit::keyboard::ModifiersState？

为什么返回 keyseq::Modifiers 而不是 winit 的自身 ModifiersState？keyseq::Modifiers 和 winit::keyboard::ModifiersState 都是通过 bitflags 包生成的。最初，这个包返回 winit 的本地修饰符结构，因为它反编译成几乎相同的东西

// keyseq::winit::pkey! { ctrl-alt-A } desugared to
( ModifiersState::CONTROL 
| ModifiersState::ALT 
| ModifiersState::empty(), winit::keyboard::KeyCode::KeyA)

// keyseq::bevy::pkey! { ctrl-alt-A } desugars to
( Modifiers::CONTROL 
| Modifiers::ALT 
| Modifiers::empty(),      bevy::prelude::KeyCode::KeyA)

然而，这些位标志与位或管道结合在一起时存在一个问题。

let modifiers: ModifiersState = ...;
match (modifiers.into(), key_code) {
    // pkey! { ctrl-alt-A }    => println!("Just pressed ctrl-alt-A!"),
    // desugared to
    (ModifiersState::CONTROL | 
     ModifiersState::ALT | 
     ModifiersState::empty(), 
     KeyCode::KeyA)            => println!("Just pressed ctrl-alt-A!"),

反编译后，位或 | 现在被解释为匹配或 |，它不匹配 ctrl-alt；它只匹配 ctrl 或 alt 或没有修饰符。（这实际上对 bitflags 生成的结构体来说似乎是一个相当大的表达能力缺陷。）

为了避免这个问题，keyseq::Modifiers 被定义为 Modifiers(pub u8)，并且位标志在宏中计算。这允许以下匹配表达式按预期工作。

match (modifiers.into(), key_code) {
    // pkey! { ctrl-alt-A }              => println!("Just pressed ctrl-alt-A!"),
    // now desugars to
    (Modifiers(3), KeyCode::KeyA)        => println!("Just pressed ctrl-alt-A!"),

    // And we can use the match-or to match multiple keychords.
    pkey! { ctrl-A } | pkey! { super-A } => println!("Just pressed ctrl-A or super-A!"),

use bevy::prelude::KeyCode;
use keyseq::{Modifiers, bevy::pkey};
assert_eq!(pkey! { ctrl-A },    (Modifiers::CONTROL, KeyCode::KeyA));
assert_eq!(pkey! { alt-A },     (Modifiers::ALT,     KeyCode::KeyA));
assert_eq!(pkey! { shift-A },   (Modifiers::SHIFT,   KeyCode::KeyA));
assert_eq!(pkey! { super-A },   (Modifiers::SUPER,   KeyCode::KeyA));
assert_eq!(pkey! { ctrl-shift-A }, 
                                (Modifiers::SHIFT |
                                 Modifiers::CONTROL, KeyCode::KeyA));

cargo run --example winit --features winit

cargo run --example bevy --features bevy