circuitpython/tests/basics/async_for2.py

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# test waiting within "async for" __anext__ function
import sys
if sys.implementation.name in ('micropython', 'circuitpython'):
# uPy allows normal generators to be awaitables
coroutine = lambda f: f
else:
import types
coroutine = types.coroutine
@coroutine
def f(x):
print('f start:', x)
yield x + 1
yield x + 2
return x + 3
class ARange:
def __init__(self, high):
print('init')
self.cur = 0
self.high = high
def __aiter__(self):
print('aiter')
return self
async def __anext__(self):
print('anext')
print('f returned:', await f(20))
if self.cur < self.high:
val = self.cur
self.cur += 1
return val
else:
raise StopAsyncIteration
async def coro():
async for x in ARange(4):
print('x', x)
o = coro()
try:
while True:
print('coro yielded:', o.send(None))
except StopIteration:
print('finished')