> @wrap_notify('remove', 'clear', 'append', 'insert', 'sort'):
> class ObservableList(ObservableCollection, list):
> pass
>
> I just can't find out the right syntax.
>
>
All right, this is working.
from contextlib import contextmanager
class ObservableCollection:
@contextmanager
def notify(cls):
print("notify before change")
yield
print("notify after change")
def wrap_notify(cls, basecls, method_names):
for method_name in method_names:
orig = getattr(basecls, method_name)
def modified(self, *args, **kwargs):
with self.notify(): return orig(self,*args,**kwargs)
setattr(cls, method_name, modified)
return cls
class ObservableDict(ObservableCollection, dict):
__slots__ = []
wrap_notify(ObservableDict, dict, ['update', '__delitem__',
'__setitem__']) # many others...
class ObservableList(ObservableCollection, list):
__slots__ = []
wrap_notify(ObservableList, list, ['append', 'pop']) # many others...
d = ObservableDict()
d[1] = 2
print(d)
But I'm still not 100% satisfied. wrap_notify is not a class decorator.
Is there a way to make a class decorator that gets the class as its
first parameter? It would be very nice:
def wrap_notify(cls, method_names):
class Wrapped(cls):
pass
for method_name in method_names:
orig = getattr(Wrapped, method_name)
def modified(self, *args, **kwargs):
with self.notify(): return orig(self,*args,**kwargs)
setattr(cls, method_name, modified)
return Wrapped
@wrap_notify(['update', '__delitem__', '__setitem__']) # many others...
class ObservableDict(ObservableCollection, dict):
__slots__ = []
@wrap_notify(['append', 'pop']) # many others...
class ObservableList(ObservableCollection, list):
__slots__ = []
And finally: is this Pythonic, or a horrible mess? Would it be better to
duplicate the body of each method one by one?
--
https://mail.python.org/mailman/listinfo/python-list
