Add on_each_tick combinator

common/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "chargrid_common"
 description = "Common utilities for making text UIs with chargrid"
-version = "0.7.0"
+version = "0.7.1"
 authors = ["Stephen Sherratt <stephen@sherra.tt>"]
 license = "MIT"
 readme = "README.md"

common/src/control_flow/boxed.rs

@@ -444,6 +444,11 @@ impl<T: 'static, S: 'static> CF<Option<T>, S> {
     pub fn pause(self) -> CF<Option<T>, S> {
         self.0.pause().boxed()
     }
+
+    /// Call a given function on each tick of the component.
+    pub fn on_each_tick<F: FnMut() + 'static>(self, f: F) -> Self {
+        self.0.on_each_tick(f).boxed()
+    }
 }
 
 impl<O: 'static> CF<O, ()> {

common/src/control_flow/unboxed.rs

@@ -397,6 +397,13 @@ impl<T, C: Component<Output = Option<T>>> CF<C> {
     pub fn pause(self) -> CF<Pause<C>> {
         cf(Pause(self.0))
     }
+
+    pub fn on_each_tick<F: FnMut()>(self, f: F) -> CF<OnEachTick<C, F>> {
+        cf(OnEachTick {
+            component: self.0,
+            f,
+        })
+    }
 }
 
 impl<C: Component<State = ()>> CF<C> {
@@ -1907,3 +1914,22 @@ where
         Size::new(width, height)
     }
 }
+
+pub struct OnEachTick<C: Component, F: FnMut()> {
+    component: C,
+    f: F,
+}
+impl<C: Component, F: FnMut()> Component for OnEachTick<C, F> {
+    type Output = C::Output;
+    type State = C::State;
+    fn render(&self, state: &Self::State, ctx: Ctx, fb: &mut FrameBuffer) {
+        self.component.render(state, ctx, fb);
+    }
+    fn update(&mut self, state: &mut Self::State, ctx: Ctx, event: Event) -> Self::Output {
+        (self.f)();
+        self.component.update(state, ctx, event)
+    }
+    fn size(&self, state: &Self::State, ctx: Ctx) -> Size {
+        self.component.size(state, ctx)
+    }
+}