circuitpython/tests/basics/async_for2.py

48 lines
1.1 KiB
Python

# test waiting within "async for" __anext__ function
# uPy allows normal generators to be awaitables.
# CircuitPython does not.
# In CircuitPython you need to have an __await__ method on an awaitable like in CPython;
# and like in CPython, generators do not have __await__.
class Awaitable:
def __init__(self, x):
self.x = x
def __await__(self):
print('f start:', self.x)
yield self.x + 1
yield self.x + 2
return self.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 Awaitable(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')