[Twisted-Python] Phasing out old-style classes
Glyph Lefkowitz
glyph at twistedmatrix.com
Sun Oct 25 00:32:08 MDT 2009
On Oct 25, 2009, at 1:50 AM, James Y Knight wrote:
> On Oct 25, 2009, at 1:38 AM, Glyph Lefkowitz wrote:
>> What do you do? Well, the obvious upgrade path here is to make a
>> class which (A) inherits from "Library" to get Twisted
>> functionality and (B) inherits from "object" to get new-style-
>> ness. So you go ahead and write:
>>
>> # in your application
>> class Application(object, Library): pass
>
> Maybe the answer "why not" is obvious and I should already know it,
> but wouldn't it be more obvious to write:
> class Application(Library, object): pass
> instead. That at least has the advantage of not blowing up if
> Library later becomes newstyle, right?
Huh. You may have just pointed out that I misunderstand the algorithm
used to generate that error. I thought that certain other hierarchies
in cases more complex than the trivial one I presented would also give
you that error if something became new-style in the middle, but I
can't seem to generate any hierarchies that cause a problem. Is it
really this simple? Always put 'object' at the *end* of your bases-
list to declare the intention "I want to be new-style" and you'll be
OK? (If so, why is that?)
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