Improved state mangement

examples/hello_world.rs

@@ -30,6 +30,17 @@ fn main() {
 
 fn app(cx: &Arc<Context>) -> Vec<Node> {
     let count = use_state(0);
+    let count2 = use_state(0);
+
+    use_effect(
+        {
+            let count2 = count2.clone();
+            move || {
+                *count2.get() += 1;
+            }
+        },
+        &[&count],
+    );
 
     cx.on_event({
         let count = count.clone();
@@ -40,5 +51,5 @@ fn app(cx: &Arc<Context>) -> Vec<Node> {
         }
     });
 
-    vec![Node::String(Arc::new(move || format!("{count}")))]
+    vec![Node::String(Arc::new(move || format!("{count} {count2}")))]
 }

src/state.rs

@@ -5,7 +5,7 @@ use std::{
 };
 
 #[derive(Clone)]
-pub struct HookEffect(Arc<Mutex<dyn Fn() + Send + Sync>>);
+pub struct HookEffect(Arc<Mutex<dyn FnMut() + Send + Sync>>);
 
 #[derive(Debug, Clone)]
 pub struct State<T> {
@@ -101,3 +101,21 @@ impl<T> DerefMut for Inner<'_, T> {
         &mut self.value
     }
 }
+
+pub trait HookDependency {
+    fn on_update(&self, hook: HookEffect);
+}
+
+impl<T> HookDependency for State<T> {
+    fn on_update(&self, hook: HookEffect) {
+        self.dependents.lock().unwrap().push(hook);
+    }
+}
+
+pub fn use_effect<F: FnMut() + Send + Sync + 'static>(f: F, dependencies: &[&dyn HookDependency]) {
+    let hook = HookEffect(Arc::new(Mutex::new(f)));
+
+    for d in dependencies {
+        d.on_update(hook.clone());
+    }
+}