On 12/05/2013 06:08 PM, Allen Li wrote:
On Thu, Dec 05, 2013 at 01:33:00PM -0800, Guido van Rossum wrote:
Actually if you want to support multiple inheritance of your ABC, your
abstract methods *must* be no-ops (or have some kind of default
behavior that can always be done last).
Done last or first really depends on what the default behavior is, doesn't it? Using __new__ as an example, the chain
of calls for that has the most ancestorish (yeah, I just made that word up ;) method doing the work first, with each
less-ancestorish method building on to that as the call chain unwinds.
I must respectfully disagree with this. If your ABCs aren't meant to be
in the MRO, then you should be @registering them as virtual classes and
not inheriting them.
Why would you think they are not meant to be in the MRO? When dealing with multiple-inheritance, there must be a base
class that does not try to call super() (object does not work for this) -- what better class to use than the base
abstract class?
The trick with Python multiple inheritance and super() (from personal
experience) is to not think of it as multiple inheritance (a tree with
cycles), but as building the MRO (linear, the same as single
inheritance).
--
~Ethan~
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