Hi Phil, Hi List,
unfortunately you do not give enough code to reproduce what you are doing,
but just guessing roughly:
you say that you have a hierarchy like B -> A -> object, with B and A
implemented in C, and then want to use B with a mixin. Programmers with a
non-python background then often write
class MyClass(B, Mixin):
"whatever"
this leads to an MRO of MyClass -> B -> Mixin -> A -> object. This is
horror if B and A are written in C, because suddenly B needs to do
something with Python code if it wants to have to do something with its
superclass Mixin, like creating a new object. I am just guessing that this
is what your code tries to do. And this is what the comment considers silly.
With
class MyClass(Mixin, B):
"whatever"
there is no problem at all. We get an MRO of MyClass -> Mixin -> B -> A ->
object. There is no need for B to do anything special, being written in C
it already knows by itself how to construct A as well, no need to fiddle
with Python at all. In general, it is usually not necessary to deal with
super() in C code at all.
The statement that there is only single inheritance on the C level becomes
obvious once you look at the MRO: that one is always linear, it is always
effectively a single inheritance. This is also why you have to call super()
only once even if you have multiple superclasses: super() just follows the
effective single inheritance of the MRO.
Hope that helps.
Cheers
Martin
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