updated taxi simulator

control/adder/coroadder0.py

@@ -0,0 +1,37 @@
+"""
+Closing a generator raises ``GeneratorExit`` at the pending ``yield``
+
+    >>> adder = adder_coro()
+    >>> next(adder)
+    >>> adder.send(10)
+    >>> adder.send(20)
+    >>> adder.send(30)
+    >>> adder.close()
+    -> total: 60  terms: 3  average: 20.0
+
+
+Other exceptions propagate to the caller:
+
+    >>> adder = adder_coro()
+    >>> next(adder)
+    >>> adder.send(10)
+    >>> adder.send('spam')
+    Traceback (most recent call last):
+      ...
+    TypeError: unsupported operand type(s) for +=: 'int' and 'str'
+
+
+"""
+
+def adder_coro(initial=0):
+    total = initial
+    num_terms = 0
+    try:
+        while True:
+            term = yield
+            total += term
+            num_terms += 1
+    except GeneratorExit:
+        average = total / num_terms
+        msg = '-> total: {}  terms: {}  average: {}'
+        print(msg.format(total, num_terms, average))