Better event handler conversion.

macros/src/html.rs

@@ -193,7 +193,7 @@ impl Element {
             let key = TokenTree::Ident(key.clone());
             let value = process_value(value);
             body.extend(quote!(
-                element.events.$key = Some(Box::new($value));
+                element.events.$key = Some(typed_html::events::IntoEventHandler::into_event_handler($value));
             ));
         }
 

typed-html/src/events.rs

@@ -112,6 +112,10 @@ pub trait EventHandler<EventType> {
     fn render(&self) -> Option<String>;
 }
 
+pub trait IntoEventHandler<E> {
+    fn into_event_handler(self) -> Box<dyn EventHandler<E>>;
+}
+
 pub struct EFn<F, E>(Option<F>, PhantomData<E>);
 
 impl<F, E> EFn<F, E>
@@ -124,6 +128,26 @@ where
     }
 }
 
+impl<F, E> IntoEventHandler<E> for EFn<F, E>
+where
+    F: FnMut(E) + 'static,
+    E: ConcreteEvent + 'static,
+{
+    fn into_event_handler(self) -> Box<dyn EventHandler<E>> {
+        Box::new(self)
+    }
+}
+
+impl<F, E> IntoEventHandler<E> for F
+where
+    F: FnMut(E) + 'static,
+    E: ConcreteEvent + 'static,
+{
+    fn into_event_handler(self) -> Box<dyn EventHandler<E>> {
+        Box::new(EFn::new(self))
+    }
+}
+
 impl<F, E> EventHandler<E> for EFn<F, E>
 where
     F: FnMut(E) + 'static,
@@ -139,7 +163,7 @@ where
     }
 }
 
-impl<'a, EventType> EventHandler<EventType> for &'a str {
+impl<E> EventHandler<E> for &'static str {
     fn attach(&mut self, _target: &Element) -> EventListenerHandle {
         panic!("Silly wabbit, strings as event handlers are only for printing.");
     }
@@ -148,3 +172,9 @@ impl<'a, EventType> EventHandler<EventType> for &'a str {
         Some(self.to_string())
     }
 }
+
+impl<E> IntoEventHandler<E> for &'static str {
+    fn into_event_handler(self) -> Box<dyn EventHandler<E>> {
+        Box::new(self)
+    }
+}

wasm/src/main.rs

@@ -6,9 +6,9 @@ extern crate typed_html;
 extern crate typed_html_macros;
 
 use stdweb::web::{self, Element, IElement, INode};
-use typed_html::for_events;
 use typed_html::dom::{Node, VNode};
-use typed_html::events::{EFn, Events};
+use typed_html::events::Events;
+use typed_html::for_events;
 use typed_html_macros::html;
 
 fn install_handlers(target: &Element, handlers: &mut Events) {
@@ -47,7 +47,7 @@ fn main() {
                 ". She is a "<em>"human girl"</em>"."
             </p>
             <p>
-                <button onclick=EFn::new(|_event| web::alert("Hello Joe!"))>
+                <button onclick=(|_event| web::alert("Hello Joe!"))>
                     "Call Joe"
                 </button>
             </p>