QTrio - a library bringing Qt GUIs together with async
and await
via Trio¶
Resources¶
Introduction¶
- Note:
This library is in early development. It works. It has tests. It has documentation. Expect breaking changes as we explore a clean API. By paying this price you get the privilege to provide feedback via GitHub issues to help shape our future.
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The QTrio project’s goal is to bring the friendly concurrency of Trio using Python’s
async
and await
syntax together with the GUI features of Qt to enable more
correct code and a more pleasant developer experience. QTrio is permissively licensed to avoid introducing
restrictions beyond those of the underlying Python Qt library you choose. Both PySide2
and PyQt5 are supported.
By enabling use of async
and await
it is possible in some cases to write related
code more concisely and clearly than you would get with the signal and slot mechanisms
of Qt concurrency.
class TwoStep:
def __init__(self, a_signal, some_path):
self.signal = a_signal
self.file = None
self.some_path = some_path
def before(self):
self.file = open(some_path, 'w')
self.signal.connect(self.after)
self.file.write('before')
def after(self, value):
self.signal.disconnect(self.after)
self.file.write(f'after {value!r}')
self.file.close()
async def together(a_signal):
with open(self.some_path, 'w') as file:
async with qtrio.enter_emissions_channel(signals=[a_signal]) as emissions:
file.write('before')
emission = await emissions.channel.receive()
[value] = emission.args
file.write(f'after {value!r}')
Note how by using async
and await
we are not only able to more clearly and
concisely describe the sequenced activity, we also get to use with
to manage the
context of the open file to be sure it gets closed.