Add async and await code samples.

jslvtr · jslvtr · commit c9584093e5bb · 2018-02-26T21:38:11.000Z
diff --git a/section12/sample_code/12_async_await.py b/section12/sample_code/12_async_await.py
@@ -0,0 +1,29 @@
+from collections import deque
+from types import coroutine
+
+friends = deque(('Rolf', 'Jose', 'Charlie', 'Jen', 'Anna'))
+
+
+@coroutine
+def friend_upper():
+    while friends:
+        friend = friends.popleft().upper()
+        greeting = yield
+        print(f'{greeting} {friend}')
+
+
+async def greet(g):
+    print('Starting...')
+    await g
+    print('Ending...')
+
+
+greeter = greet(friend_upper())
+greeter.send(None)
+greeter.send('Hello')
+
+greeting = input('Enter a greeting: ')
+greeter.send(greeting)
+
+greeting = input('Enter a greeting: ')
+greeter.send(greeting)
