In <[email protected]> kj <[email protected]> writes:
>At any rate, using your [i.e. Arnaud's] suggestions in this and
>your other post, the current implementation of frozendict stands
>at:
>class frozendict(dict):
> for method in ('__delitem__ __setitem__ clear pop popitem setdefault '
> 'update').split():
> exec """
>def %s(self, *a, **k):
> cn = self.__class__.__name__
> raise TypeError("'%%s' object is not mutable" %% cn)
>""" % method
> def __hash__(self):
> return hash(frozenset(self.items()))
>...which is a lot nicer!
As a side comment on my own post, this is the second time in less
than a week that I find myself having to resort to exec'ing some
code generated from a template. This one is worse, because there's
nothing runtime-dependent about the code being exec'd. It sticks
in my craw somehow. It just doesn't seem quite right that at the
time of doing something as bread-and-butter as implementing a
subclass, one has to choose between explicitly writing a whole
bunch of identical methods, and exec-based hacks like what I'm
doing above. There's got to be a "better" to tell Python: "override
all these superclass methods with this one."
Or maybe the problem here is that, in a perfect world, frozendict
would be in the standard library, as a superclass of dict lacking
all of dict's destructive methods. :)
~kj
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