Get delegates working so speech interruption/queuing should now be possible.

* Fix broken delegate method signature.
* Add `NSRunLoop` into `hello_world` example so delegates are called. Presumably, MacOS apps already run one of these, but the example didn't.

examples/hello_world.rs

@@ -1,5 +1,12 @@
 use std::io;
 
+#[cfg(target_os = "macos")]
+use cocoa_foundation::base::id;
+#[cfg(target_os = "macos")]
+use cocoa_foundation::foundation::NSRunLoop;
+#[cfg(target_os = "macos")]
+use objc::{msg_send, sel, sel_impl};
+
 use tts::*;
 
 fn main() -> Result<(), Error> {
@@ -42,6 +49,13 @@ fn main() -> Result<(), Error> {
     }
     tts.speak("Goodbye.", false)?;
     let mut _input = String::new();
+    #[cfg(target_os = "macos")]
+    {
+        let run_loop: id = unsafe { NSRunLoop::currentRunLoop() };
+        unsafe {
+            let _: () = msg_send![run_loop, run];
+        }
+    }
     io::stdin().read_line(&mut _input)?;
     Ok(())
 }

src/backends/ns_speech_synthesizer.rs

@@ -17,18 +17,24 @@ impl NSSpeechSynthesizerBackend {
         let mut obj: *mut Object = unsafe { msg_send![class!(NSSpeechSynthesizer), alloc] };
         obj = unsafe { msg_send![obj, init] };
         let mut decl = ClassDecl::new("MyNSSpeechSynthesizerDelegate", class!(NSObject)).unwrap();
-        extern "C" fn speech_synthesizer_did_finish_speaking(_: &Object, _: Sel, _: BOOL) {
+        extern "C" fn speech_synthesizer_did_finish_speaking(
+            _: &Object,
+            _: Sel,
+            _: *const Object,
+            _: BOOL,
+        ) {
             println!("Got it");
         }
         unsafe {
             decl.add_method(
-                sel!(didFinishSpeaking:),
-                speech_synthesizer_did_finish_speaking as extern "C" fn(&Object, Sel, BOOL) -> (),
+                sel!(speechSynthesizer:didFinishSpeaking:),
+                speech_synthesizer_did_finish_speaking
+                    as extern "C" fn(&Object, Sel, *const Object, BOOL) -> (),
             )
         };
         let delegate_class = decl.register();
         let delegate_obj: *mut Object = unsafe { msg_send![delegate_class, new] };
-        let _: () = unsafe { msg_send![obj, setDelegate: delegate_obj] };
+        let _: Object = unsafe { msg_send![obj, setDelegate: delegate_obj] };
         NSSpeechSynthesizerBackend(obj, delegate_obj)
     }
 }