On 2/20/06, Brett Cannon <[EMAIL PROTECTED]> wrote: > While #3 is my preferred solution as well, it does pose a Liskov > violation if this is a direct dict subclass instead of storing a dict > internally (can't remember the name of the design pattern that does > this). But I think it is good to have the constructor be different > since it does also help drive home the point that this is not a > standard dict.
I've heard this argument a few times now from different folks and I'm tired of it. It's wrong. It's not true. It's a dead argument. It's pushing up the daisies, so to speak. Please stop abusing Barbara Liskov's name and remember that the constructor signature is *not* part of the interface to an instance! Changing the constructor signature in a subclass does *not* cause *any* "Liskov" violations because the constructor is not called by *users* of the object -- it is only called to *create* an object. As the *user* of an object you're not allowed to *create* another instance (unless the object provides an explicit API to do so, of course, in which case you deal with that API's signature, not with the constructor). -- --Guido van Rossum (home page: http://www.python.org/~guido/) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
