allow returning values from use_eval

examples/eval.rs

@@ -1,4 +1,5 @@
 use dioxus::prelude::*;
+use dioxus_desktop::EvalResult;
 
 fn main() {
     dioxus_desktop::launch(app);
@@ -7,6 +8,15 @@ fn main() {
 fn app(cx: Scope) -> Element {
     let script = use_state(&cx, String::new);
     let eval = dioxus_desktop::use_eval(&cx);
+    let future: &UseRef<Option<EvalResult>> = use_ref(&cx, || None);
+    if future.read().is_some() {
+        let future_clone = future.clone();
+        cx.spawn(async move {
+            if let Some(fut) = future_clone.with_mut(|o| o.take()) {
+                println!("{:?}", fut.await)
+            }
+        });
+    }
 
     cx.render(rsx! {
         div {
@@ -16,7 +26,10 @@ fn app(cx: Scope) -> Element {
                 oninput: move |e| script.set(e.value.clone()),
             }
             button {
-                onclick: move |_| eval(script),
+                onclick: move |_| {
+                    let fut = eval(script);
+                    future.set(Some(fut));
+                },
                 "Execute"
             }
         }