[Python-Dev] Concerns about method overriding and subclassing with dataclasses

[Ethan Smith]

On Mon, Jan 1, 2018 at 5:03 PM, Chris Barker <chris.barker at noaa.gov> wrote:

> On Sat, Dec 30, 2017 at 7:27 AM, Stephen J. Turnbull <
> turnbull.stephen.fw at u.tsukuba.ac.jp> wrote:
>
>>   Just use the simple rule that a new
>> __repr__ is generated unless provided in the dataclass.
>>
>
> are we only talking about __repr__ here ???
>
> I interpretted Guido's proposal as being about all methods -- we _may_
> want something special for __repr__, but I hope not.
>
> But +1 for Guido's proposal, not only because it's easy to explain, but
> because it more naturally follows the usual inheritance logic:
>
> The decorator's entire point is to auto-generate boilerplate code for you.
> Once it's done that it shouldn't, in the end, behave any differently than
> if you hand wrote that code. If you hand wrote the methods that the
> decorator creates for you, they would override any base class versions. So
> that's what it should do.
>
> And the fact that you can optionally tell it not to in some particular
> case keeps full flexibility.
>
> -CHB
>

I interpreted this to be for all methods as well, which makes sense.
Special casing just __repr__ doesn't make sense to me, but I will wait for
Guido to clarify.

>
> > I grant that there may be many reasons why one would be deriving
>
>> dataclasses from dataclasses
>
>
> Will you get the "right" __repr__ now if you derive a datacalss from a
> dataclass? That would be a nice feature.
>

The __repr__ will be generated by the child dataclass unless the user
overrides it. So I believe this is the "right" __repr__.

~>Ethan Smith

>
> -CHB
>
> --
>
> Christopher Barker, Ph.D.
> Oceanographer
>
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>
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