clean up mod command

src/menu.rs

@@ -0,0 +1,63 @@
+use crate::*;
+pub struct MenuBar<E: Engine, S, C: Command<S>> {
+    pub menus: Vec<Menu<E, S, C>>,
+    pub index: usize,
+}
+impl<E: Engine, S, C: Command<S>> MenuBar<E, S, C> {
+    pub fn new () -> Self { Self { menus: vec![], index: 0 } }
+    pub fn add (mut self, menu: Menu<E, S, C>) -> Self {
+        self.menus.push(menu);
+        self
+    }
+}
+pub struct Menu<E: Engine, S, C: Command<S>> {
+    pub title: String,
+    pub items: Vec<MenuItem<E, S, C>>,
+    pub index: Option<usize>,
+}
+impl<E: Engine, S, C: Command<S>> Menu<E, S, C> {
+    pub fn new (title: impl AsRef<str>) -> Self {
+        Self {
+            title: title.as_ref().to_string(),
+            items: vec![],
+            index: None,
+        }
+    }
+    pub fn add (mut self, item: MenuItem<E, S, C>) -> Self {
+        self.items.push(item);
+        self
+    }
+    pub fn sep (mut self) -> Self {
+        self.items.push(MenuItem::sep());
+        self
+    }
+    pub fn cmd (mut self, hotkey: &'static str, text: &'static str, command: C) -> Self {
+     self.items.push(MenuItem::cmd(hotkey, text, command));
+        self
+    }
+    pub fn off (mut self, hotkey: &'static str, text: &'static str) -> Self {
+        self.items.push(MenuItem::off(hotkey, text));
+        self
+    }
+}
+pub enum MenuItem<E: Engine, S, C: Command<S>> {
+    /// Unused.
+    __(PhantomData<E>, PhantomData<S>),
+    /// A separator. Skip it.
+    Separator,
+    /// A menu item with command, description and hotkey.
+    Command(&'static str, &'static str, C),
+    /// A menu item that can't be activated but has description and hotkey
+    Disabled(&'static str, &'static str)
+}
+impl<E: Engine, S, C: Command<S>> MenuItem<E, S, C> {
+    pub fn sep () -> Self {
+        Self::Separator
+    }
+    pub fn cmd (hotkey: &'static str, text: &'static str, command: C) -> Self {
+        Self::Command(hotkey, text, command)
+    }
+    pub fn off (hotkey: &'static str, text: &'static str) -> Self {
+        Self::Disabled(hotkey, text)
+    }
+}