Hi Jeroen, On 2016-10-10, Jeroen Demeyer <jdeme...@cage.ugent.be> wrote: > On 2016-10-10 10:47, Simon King wrote: >> The meta-metaclass would take the >> atomic metaclasses appearing in the bases of a class definition "Foo", >> and would automatically/dynamically create a composed metaclass, that >> combines all the features of the given atomic metaclasses and would >> serve as the metaclass of the resulting class "Foo". > > I have tried that. It is possible in Python 2 but (as far as I know) not > in Python 3. In Python 2, when doing > > class X(B1, ..., Bn) > > The metaclass of B1 is responsible for constructing the class X (in > particular, the metaclass of B1 can decide the metaclass of X). In > Python 3, the metaclass of X is resolved by a hard-coded algorithm > _PyType_CalculateMetaclass and then that metaclass constructs the class X. > > Of course, all this is completely undocumented.
Seriously? That's a regression. Having single-purpose metaclasses that can smoothly blend would have been a nice feature. Best regards, Simon -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
