draft of coroutine examples

control/coroaverager0.py

@@ -0,0 +1,25 @@
+# BEGIN CORO_AVERAGER
+"""
+A coroutine to compute a running average
+
+    >>> coro_avg = averager()  # <1>
+    >>> next(coro_avg)  # <2>
+    0.0
+    >>> coro_avg.send(10)  # <3>
+    10.0
+    >>> coro_avg.send(30)
+    20.0
+    >>> coro_avg.send(5)
+    15.0
+
+"""
+
+def averager():
+    total = average = 0.0
+    count = 0
+    while True:
+        term = yield average  # <4>
+        total += term
+        count += 1
+        average = total/count
+# END CORO_AVERAGER