cmdsys: delegate handling

crates/tek_core/src/command.rs

@@ -4,6 +4,14 @@ pub trait Command<S>: Sized {
     fn translate (self, _: &S) -> Self { self }
     fn execute (self, state: &mut S) -> Perhaps<Self>;
 }
+pub fn delegate <B, C: Command<S>, S> (
+    wrap:  impl Fn(C)->B,
+    state: &mut S,
+    cmd:   C
+) -> Perhaps<B> {
+    Ok(cmd.execute(state)?.map(|x|wrap(x)))
+}
+
 pub trait MatchInput<E: Engine, S>: Sized {
     fn match_input (state: &S, input: &E::Input) -> Option<Self>;
 }

crates/tek_core/src/focus.rs

@@ -1,27 +1,16 @@
 use crate::*;
 
-#[derive(Clone, PartialEq)]
-pub enum FocusCommand {
-    Next,
-    Prev,
-    Up,
-    Down,
-    Left,
-    Right,
-    Enter,
-    Exit
-}
-
-pub trait FocusGrid<T: Copy + PartialEq> {
-    fn layout (&self) -> &[&[T]];
+pub trait FocusGrid {
+    type Item: Copy + PartialEq;
+    fn layout (&self) -> &[&[Self::Item]];
     fn cursor (&self) -> (usize, usize);
     fn cursor_mut (&mut self) -> &mut (usize, usize);
     fn update_focus (&mut self) {}
-    fn focused (&self) -> &T {
+    fn focused (&self) -> &Self::Item {
         let (x, y) = self.cursor();
         &self.layout()[y][x]
     }
-    fn focus (&mut self, target: T) {
+    fn focus (&mut self, target: Self::Item) {
         while self.focused() != &target {
             self.focus_next()
         }
@@ -90,4 +79,35 @@ pub trait FocusGrid<T: Copy + PartialEq> {
         }
         self.update_focus();
     }
+    fn focus_enter (&mut self) {}
+    fn focus_exit (&mut self) {}
+}
+
+#[derive(Clone, PartialEq)]
+pub enum FocusCommand {
+    Next,
+    Prev,
+    Up,
+    Down,
+    Left,
+    Right,
+    Enter,
+    Exit
+}
+
+impl<F: FocusGrid> Command<F> for FocusCommand {
+    fn execute (self, state: &mut F) -> Perhaps<FocusCommand> {
+        use FocusCommand::*;
+        match self {
+            Next  => { state.focus_next();  },
+            Prev  => { state.focus_prev();  },
+            Up    => { state.focus_up();    },
+            Down  => { state.focus_down();  },
+            Left  => { state.focus_left();  },
+            Right => { state.focus_right(); },
+            Enter => { state.focus_enter(); },
+            Exit  => { state.focus_exit();  },
+        }
+        Ok(None)
+    }
 }