At 09:05 PM 1/12/05 +0100, Alex Martelli wrote:
On 2005 Jan 12, at 20:39, Phillip J. Eby wrote:It's burned me more than just a few times, and I *still* sometimes make it if I'm not paying attention. It's just too easy to make the mistake. So, I'm actually open to considering dropping interface inheritance.
What about accepting Microsoft's QueryInterface precedent for this? I know that "MS" is a dirty word to many, but I did like much of what they did in COM, personally. The QI precedent would be: you can inherit interface from interface, but that does NOT intrinsically imply substitutability -- it just means the inheriting interface has all the methods of the one being subclassed, with the same signatures, without having to do a nasty copy-and-paste. Of course, one presumably could use NO_ADAPTER_NEEDED to easily (but explicitly: that makes a difference!) implement the common case in which the inheriting interface DOES want to assert that it's perfectly / losslessly / etc substitutable for the one being inherited.
Well, you and I may agree to this, but we can't agree on behalf of everybody else who hasn't been bitten by this problem, I'm afraid.
I checked PEAK and about 62 out of 150 interfaces inherited from anything else; it would not be a big deal to explicitly do the NO_ADAPTER_NEEDED thing, especially since PyProtocols has an 'advise' keyword that does the declaration, anyway; inheritance is just a shortcut for that declaration when you are using only one kind of interface, so the "explicit" way of defining NO_ADAPTER_NEEDED between two interfaces has only gotten used when mixing Zope or Twisted interfaces w/PyProtocols.
Anyway, I'm at least +0 on dropping this; the reservation is just because I don't think everybody else will agree with this, and don't want to be appearing to imply that consensus between you and me implies any sort of community consensus on this point. That is, the adaptation from "Alex and Phillip agree" to "community agrees" is noisy at best! ;)
_______________________________________________ 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
