updated taxi simulator

control/adder/adder.py

@@ -0,0 +1,42 @@
+import sys
+
+
+def ask():
+    prompt = '>'
+    while True:
+        response = input(prompt)
+        if not response:
+            return 0
+        yield response
+
+
+def parse_args():
+    yield from iter(sys.argv[1:])
+
+
+def fetch(producer):
+    gen = producer()
+    next(gen)
+    yield from gen
+
+
+def main(args):
+    if args:
+        producer = parse_args
+    else:
+        producer = ask
+
+    total = 0
+    count = 0
+    gen = fetch(producer())
+    while True:
+        term = yield from gen
+        term = float(term)
+        total += term
+        count += 1
+        average = total / count
+        print('total: {}  average: {}'.format(total, average))
+
+
+if __name__ == '__main__':
+    main(sys.argv[1:])

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))

control/adder/yetanother.py

@@ -0,0 +1,47 @@
+import sys
+import collections
+
+Result = collections.namedtuple('Result', 'total average')
+
+def adder():
+    total = 0
+    count = 0
+    while True:
+        term = yield
+        try:
+            term = float(term)
+        except (ValueError, TypeError):
+            break
+        else:
+            total += term
+            count += 1
+    return Result(total, total/count)
+
+def process_args(coro, args):
+    for arg in args:
+        coro.send(arg)
+    try:
+        next(coro)
+    except StopIteration as exc:
+        return exc.value
+
+
+def prompt(coro):
+    while True:
+        term = input('+> ')
+        try:
+            coro.send(term)
+        except StopIteration as exc:
+            return exc.value
+
+
+def main():
+    coro = adder()
+    next(coro)  # prime it
+    if len(sys.argv) > 1:
+        res = process_args(coro, sys.argv[1:])
+    else:
+        res = prompt(coro)
+    print(res)
+
+main()