[Python-Dev] Submitting PEP 422 (Simple class initialization hook) for pronouncement
PJ Eby
pje at telecommunity.com
Sun Feb 10 22:27:49 CET 2013
On Sun, Feb 10, 2013 at 7:32 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> class Example:
> @classmethod
> def __init_class__(cls):
Is the @classmethod required? What happens if it's not present?
Second, will type have a default __init_class__? (IMO, it should,
otherwise it will be impossible to write co-operative __init_class__
functions.)
Only other comment is that the PEP could use a more concrete use case, e.g.:
class Record:
__fields = {}
@classmethod
def __init_class__(cls):
cls.__fields = dict(cls.__fields) # inherited fields
cls.__fields.update({attr:val for attr, val in
cls.__dict__.iteritems() if isinstance(val, Field)})
super().__init_class__() # be co-operative
# ...other methods that use the __fields attribute
class SomeRecord(Record):
foo = Field(int)
bar = Field(str)
Putting something like this early on might help to demonstrate the
usefulness of the feature on its own merits, independent of the
porting issue, etc. ;-)
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