fix: fix menu mnemonics (#640)

.changes/fix-mnemonic-on-linux.md

@@ -0,0 +1,5 @@
+---
+"tao": "patch"
+---
+
+On Linux, fix menu item mnemonics.

.changes/macos-strip-mnemonics.md

@@ -0,0 +1,5 @@
+---
+"tao": "patch"
+---
+
+On macOS, strip menu mnemonics for consistency with other platforms.

src/menu.rs

@@ -55,9 +55,12 @@ pub struct MenuItemAttributes<'a> {
 impl<'a> MenuItemAttributes<'a> {
   /// Creates a new custom menu item.
   ///
-  /// ## Platform-specific
+  /// `title` could optionally contain an `&` before a character to assign this character as the mnemonic
+  /// for this menu item. To display a `&` without assigning a mnemenonic, use `&&`
+  ///
+  /// ## Platform-specific:
   ///
-  /// - **Linux:** `selected` render a regular item
+  /// - **macOS**: mnemonics are not supported but single `&` will be rmeoved anyways for consistency with other platforms.
   pub fn new(title: &'a str) -> Self {
     Self {
       id: MenuId::new(title),
@@ -92,6 +95,10 @@ impl<'a> MenuItemAttributes<'a> {
   }
 
   /// Assign default checkbox style.
+  ///
+  /// Default is `false`
+  ///
+  /// If `selected` is `false`, renders a regular menu item.
   pub fn with_selected(mut self, selected: bool) -> Self {
     self.selected = selected;
     self
@@ -117,6 +124,13 @@ impl ContextMenu {
   }
 
   /// Add a submenu.
+  ///
+  /// `title` could optionally contain an `&` before a character to assign this character as the mnemonic
+  /// for this menu item. To display a `&` without assigning a mnemenonic, use `&&`
+  ///
+  /// ## Platform-specific:
+  ///
+  /// - **macOS**: mnemonics are not supported but single `&` will be rmeoved anyways for consistency with other platforms.
   pub fn add_submenu(&mut self, title: &str, enabled: bool, submenu: ContextMenu) {
     self
       .0
@@ -158,6 +172,13 @@ impl MenuBar {
   }
 
   /// Add a submenu.
+  ///
+  /// `title` could optionally contain an `&` before a character to assign this character as the mnemonic
+  /// for this menu item. To display a `&` without assigning a mnemenonic, use `&&`
+  ///
+  /// ## Platform-specific:
+  ///
+  /// - **macOS**: mnemonics are not supported but single `&` will be rmeoved anyways for consistency with other platforms.
   pub fn add_submenu(&mut self, title: &str, enabled: bool, submenu: MenuBar) {
     self
       .0

src/platform_impl/linux/menu.rs

@@ -85,13 +85,14 @@ impl MenuItemAttributes {
       .gtk_item
       .label()
       .map(|gstr| gstr.as_str().to_owned())
-      .unwrap_or("".to_owned())
+      .map(|label| from_gtk_mnemonic(&label))
+      .unwrap_or_default()
   }
   pub fn set_enabled(&mut self, is_enabled: bool) {
     self.gtk_item.set_sensitive(is_enabled);
   }
   pub fn set_title(&mut self, title: &str) {
-    self.gtk_item.set_label(title);
+    self.gtk_item.set_label(&to_gtk_mnemonic(title));
   }
 
   pub fn set_selected(&mut self, is_selected: bool) {
@@ -129,12 +130,13 @@ impl Menu {
     selected: bool,
     menu_type: MenuType,
   ) -> CustomMenuItem {
+    let title = to_gtk_mnemonic(&title);
     let gtk_item = if selected {
-      let item = CheckMenuItem::with_label(title);
+      let item = CheckMenuItem::with_label(&title);
       item.set_active(true);
       item.upcast::<GtkMenuItem>()
     } else {
-      GtkMenuItem::with_label(title)
+      GtkMenuItem::with_label(&title)
     };
     let custom_menu = MenuItemAttributes {
       id: menu_id,
@@ -403,3 +405,20 @@ fn modifiers_to_gdk_modifier_type(modifiers: ModifiersState) -> gdk::ModifierTyp
 
   result
 }
+
+pub fn to_gtk_mnemonic<S: AsRef<str>>(string: S) -> String {
+  string
+    .as_ref()
+    .replace("&&", "[~~]")
+    .replace('&', "_")
+    .replace("[~~]", "&&")
+    .replace("[~~]", "&")
+}
+
+pub fn from_gtk_mnemonic<S: AsRef<str>>(string: S) -> String {
+  string
+    .as_ref()
+    .replace("__", "[~~]")
+    .replace('_', "&")
+    .replace("[~~]", "__")
+}

src/platform_impl/macos/menu.rs

@@ -69,8 +69,9 @@ impl MenuItemAttributes {
     }
   }
   pub fn set_title(&mut self, title: &str) {
+    let title = super::util::strip_mnemonic(title);
     unsafe {
-      let menu_title = NSString::alloc(nil).init_str(title);
+      let menu_title = NSString::alloc(nil).init_str(&title);
       self.1.setTitle_(menu_title);
     }
   }
@@ -160,7 +161,8 @@ impl Menu {
 
   pub fn add_submenu(&mut self, title: &str, enabled: bool, submenu: Menu) {
     unsafe {
-      let menu_title = NSString::alloc(nil).init_str(title);
+      let title = super::util::strip_mnemonic(title);
+      let menu_title = NSString::alloc(nil).init_str(&title);
       let menu_item = NSMenuItem::alloc(nil).autorelease();
       let () = msg_send![submenu.menu, setTitle: menu_title];
       let () = msg_send![menu_item, setTitle: menu_title];
@@ -360,14 +362,16 @@ pub(crate) fn make_custom_menu_item(
   accelerators: Option<Accelerator>,
   menu_type: MenuType,
 ) -> *mut Object {
+  let title = super::util::strip_mnemonic(title);
+
   let alloc = make_menu_alloc();
   let menu_id = Box::new(Action(Box::new(id.0)));
   let ptr = Box::into_raw(menu_id);
 
   unsafe {
     (&mut *alloc).set_ivar(BLOCK_PTR, ptr as usize);
     let _: () = msg_send![&*alloc, setTarget:&*alloc];
-    let title = NSString::alloc(nil).init_str(title);
+    let title = NSString::alloc(nil).init_str(&title);
     make_menu_item_from_alloc(alloc, title, selector, accelerators, menu_type)
   }
 }

src/platform_impl/macos/util/mod.rs

@@ -181,3 +181,14 @@ pub unsafe fn toggle_style_mask(window: id, view: id, mask: NSWindowStyleMask, o
   // If we don't do this, key handling will break. Therefore, never call `setStyleMask` directly!
   window.makeFirstResponder_(view);
 }
+
+/// Strips single `&` characters from the string.
+///
+/// `&` can be escaped as `&&` to prevent stripping, in which case a single `&` will be output.
+pub fn strip_mnemonic<S: AsRef<str>>(string: S) -> String {
+  string
+    .as_ref()
+    .replace("&&", "[~~]")
+    .replace('&', "")
+    .replace("[~~]", "&")
+}