Yes, I see what you're saying. However, I don't understand why __init_subclass__ (defined on some class C) cannot be used to implement the checks required by @abstractmethod instead of doing it in ABCMeta. This would prevent metaclass conflicts since you could use @abstractmethod with any metaclass or no metaclass at all provided you inherit from C.
On Tue, Jul 19, 2016 at 12:21 AM Nick Coghlan <ncogh...@gmail.com> wrote: > On 19 July 2016 at 09:26, Neil Girdhar <mistersh...@gmail.com> wrote: > > Yes, I'm very excited about this! > > > > Will this mean no more metaclass conflicts if using @abstractmethod? > > ABCMeta and EnumMeta both create persistent behavioural differences > rather than only influencing subtype definition, so they'll need to > remain as custom metaclasses. > > What this PEP (especially in combination with PEP 520) is aimed at > enabling is subclassing APIs designed more around the notion of > "implicit class decoration" where a common base class or mixin can be > adjusted to perform certain actions whenever a new subclass is > defined, without changing the runtime behaviour of those subclasses. > (For example: a mixin or base class may require that certain > parameters be set as class attributes - this PEP will allow the base > class to check for those and throw an error at definition time, rather > than getting a potentially cryptic error when it attempts to use the > missing attribute) > > Cheers, > Nick. > > -- > Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia >
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