add checkmark for menu items

src/appkit/menu/item.rs

@@ -36,7 +36,7 @@ fn make_menu_item<S: AsRef<str>>(
     title: S,
     key: Option<&str>,
     action: Option<Sel>,
-    modifiers: Option<&[EventModifierFlag]>
+    modifiers: Option<&[EventModifierFlag]>,
 ) -> Id<Object, Owned> {
     unsafe {
         let title = NSString::new(title.as_ref());
@@ -44,7 +44,7 @@ fn make_menu_item<S: AsRef<str>>(
         // Note that AppKit requires a blank string if nil, not nil.
         let key = NSString::new(match key {
             Some(s) => s,
-            None => ""
+            None => "",
         });
 
         // Stock menu items that use selectors targeted at system pieces are just standard
@@ -63,7 +63,7 @@ fn make_menu_item<S: AsRef<str>>(
                 initWithTitle: &*title,
                 action: sel!(fireBlockAction:),
                 keyEquivalent: &*key,
-            ]
+            ],
         };
 
         if let Some(modifiers) = modifiers {
@@ -151,7 +151,7 @@ pub enum MenuItem {
 
     /// Represents a Separator. It's useful nonetheless for
     /// separating out pieces of the `NSMenu` structure.
-    Separator
+    Separator,
 }
 
 impl MenuItem {
@@ -186,7 +186,7 @@ impl MenuItem {
                 "Hide Others",
                 Some("h"),
                 Some(sel!(hide:)),
-                Some(&[EventModifierFlag::Command, EventModifierFlag::Option])
+                Some(&[EventModifierFlag::Command, EventModifierFlag::Option]),
             ),
 
             Self::ShowAll => make_menu_item("Show All", None, Some(sel!(unhideAllApplications:)), None),
@@ -203,7 +203,7 @@ impl MenuItem {
                 "Enter Full Screen",
                 Some("f"),
                 Some(sel!(toggleFullScreen:)),
-                Some(&[EventModifierFlag::Command, EventModifierFlag::Control])
+                Some(&[EventModifierFlag::Command, EventModifierFlag::Control]),
             ),
 
             Self::Minimize => make_menu_item("Minimize", Some("m"), Some(sel!(performMiniaturize:)), None),
@@ -213,13 +213,13 @@ impl MenuItem {
                 "Toggle Sidebar",
                 Some("s"),
                 Some(sel!(toggleSidebar:)),
-                Some(&[EventModifierFlag::Command, EventModifierFlag::Option])
+                Some(&[EventModifierFlag::Command, EventModifierFlag::Option]),
             ),
 
             Self::Separator => {
                 let cls = class!(NSMenuItem);
                 msg_send_id![cls, separatorItem]
-            }
+            },
         }
     }
 
@@ -287,6 +287,19 @@ impl MenuItem {
 
         self
     }
+
+    pub fn checkmark(self, enabled: bool) -> Self {
+        if let MenuItem::Custom(objc) = self {
+            unsafe {
+                let enabled: NSUInteger = if enabled { 1 } else { 0 };
+                let _: () = msg_send![&*objc, setState: enabled];
+            }
+
+            return MenuItem::Custom(objc);
+        }
+
+        self
+    }
 }
 
 /// On the Objective-C side, we need to ensure our handler is dropped when this subclass