T08: keys: xterm and kitty encoding, Option as Alt by side, IME composition at the cursor; shot types real AppKit keys

src/term/mac.rs

@@ -0,0 +1,45 @@
+use objc::{
+    class, msg_send,
+    runtime::{NO, Object},
+    sel, sel_impl,
+};
+
+/// AppKit's event types for a key going down and coming up.
+const KEY_DOWN: u64 = 10;
+const KEY_UP: u64 = 11;
+
+/// The device bits of the left and right Option keys in an event's modifier flags.
+const LEFT_OPTION: u64 = 0x20;
+const RIGHT_OPTION: u64 = 0x40;
+
+/// Which Option keys are down in the key event AppKit is handling: left, then right.
+pub fn option_sides() -> anyhow::Result<(bool, bool)> {
+    unsafe {
+        let app: *mut Object = msg_send![class!(NSApplication), sharedApplication];
+        let event: *mut Object = msg_send![app, currentEvent];
+        anyhow::ensure!(!event.is_null(), "macOS: no key event to read Option from");
+        let kind: u64 = msg_send![event, type];
+        anyhow::ensure!(
+            kind == KEY_DOWN || kind == KEY_UP,
+            "macOS: the current event is type {kind}, not a key"
+        );
+        let flags: u64 = msg_send![event, modifierFlags];
+        Ok((flags & LEFT_OPTION != 0, flags & RIGHT_OPTION != 0))
+    }
+}
+
+/// Turns off the accent menu a held key opens, so held keys repeat as in other terminals.
+pub fn repeat_held_keys() {
+    unsafe {
+        let key: *mut Object = msg_send![
+            class!(NSString),
+            stringWithUTF8String: c"ApplePressAndHoldEnabled".as_ptr()
+        ];
+        let off: *mut Object = msg_send![class!(NSNumber), numberWithBool: NO];
+        let defaults: *mut Object =
+            msg_send![class!(NSDictionary), dictionaryWithObject: off forKey: key];
+        let store: *mut Object = msg_send![class!(NSUserDefaults), standardUserDefaults];
+        let _: () = msg_send![store, registerDefaults: defaults];
+    }
+    log::info!("macOS: held keys repeat");
+}