def __get__(self, instance, cls=None):
if instance is None:
owner = cls
else:
owner = instance
key = id(owner)
try:
return self._instance_signals[key]
except KeyError:
pass
parent = None
signature = self.signature
if instance is None:
extra_arg = inspect.Parameter(
name='sender',
kind=inspect.Parameter.KEYWORD_ONLY,
default=None)
def _params_gen():
existing = iter(signature.parameters.values())
for param in existing:
if param.kind in (inspect.Parameter.KEYWORD_ONLY,
inspect.Parameter.VAR_KEYWORD):
yield extra_arg
yield param
break
else:
yield param
else:
yield extra_arg
yield from existing
signature = signature.replace(parameters=list(_params_gen()))
else:
if cls:
parent = self.__get__(None, cls)
finalize(owner, self._instance_signals.pop, key, None)
new_signal = type(self)(self.name, doc=self.__doc__,
signature=signature, _owner=owner)
if parent:
new_signal.connect(parent,
arg_adapter=_sender_arg_adapter(instance))
self._instance_signals[key] = new_signal
return new_signal
def __set__(self, instance, value):
exp = coerce(value, size=self._size)
if id(instance) not in self._instance_expressions:
finalize(instance, self._instance_expressions.pop,
id(instance), None)
self._instance_expressions[id(instance)] = simplify(exp)
