Switch to async/await syntax

docs/example.rst

@@ -10,16 +10,14 @@ Simple example::
     import asyncio
     from aiohttp import web
 
-    @asyncio.coroutine
-    def root_handler(request):
+    async def root_handler(request):
         text = "Alive and kicking!"
         return web.Response(body=text.encode('utf-8'))
 
     # option 2: auth at a higher level?
     # set user_id and allowed in the wsgi handler
     @protect('view_user')
-    @asyncio.coroutine
-    def user_handler(request):
+    async def user_handler(request):
         name = request.match_info.get('name', "Anonymous")
         text = "Hello, " + name
         return web.Response(body=text.encode('utf-8'))
@@ -27,14 +25,12 @@ Simple example::
 
     # option 3: super low
     # wsgi doesn't do anything
-    @asyncio.coroutine
-    def user_update_handler(request):
+    async def user_update_handler(request):
         # identity, asked_permission
-        user_id = yield from identity_policy.identify(request)
-        identity = yield from auth_policy.authorized_user_id(user_id)
-        allowed = yield from request.auth_policy.permits(
-                identity, asked_permission
-                )
+        user_id = await identity_policy.identify(request)
+        identity = await auth_policy.authorized_user_id(user_id)
+        allowed = await request.auth_policy.permits(identity,
+                                                    asked_permission)
         if not allowed:
             # how is this pluggable as well?
             # ? return NotAllowedStream()
@@ -42,8 +38,7 @@ Simple example::
 
         update_user()
 
-    @asyncio.coroutine
-    def init(loop):
+    async def init(loop):
         # set up identity and auth
         auth_policy = DictionaryAuthorizationPolicy({'me': ('view_user',),
                                                      'you': ('view_user',
@@ -60,7 +55,7 @@ Simple example::
         app.router.add_route('GET', '/{user}/edit', user_update_handler)
 
         # get it started
-        srv = yield from loop.create_server(app.make_handler(),
+        srv = await loop.create_server(app.make_handler(),
                                             '127.0.0.1', 8080)
         print("Server started at http://127.0.0.1:8080")
         return srv