[Python-ideas] Where to put non-collection ABCs (was: Deprecating the old-style sequence protocol)

[Michael Selik]

On Thu, Dec 31, 2015 at 12:48 PM Brett Cannon <brett at python.org> wrote:

>
>
> On Thu, Dec 31, 2015, 07:08 Alexander Walters <tritium-list at sdamon.com>
> wrote:
>
>> Would it be a good idea to mix 'concrete implementations of ABCs'*
>> directly in the abc module where the tooling to create ABCs live, or to
>> put it in a submodule?  I feel it should be a submodule, but that isn't
>> based on vast experience.
>>
>
Locating collections ABCs in a submodule makes some sense, as there are 21
of them and the collections module is important for beginners to learn
without getting distracted by ABCs. Contrast that with the direct inclusion
of ABCs in most other modules and it suggests the creation of a submodule
for collections may have been motivated for the same reason as this
discussion -- it didn't feel right to have certain ABCs directly in the
collections module.

If the non-collection ABCs are being moved out of the collections module
and into the ``abc`` module, there's less reason to separate them into a
submodule. Beginners don't venture into the abc module expecting to
understand everything. It's natural to find a bunch of ABCs in a module
called ``abc``. And ABCs are included directly in many other modules
instead of being relegated to a less discoverable submodule like
``typing.abc``, ``io.abc``, ``numbers.abc``, etc. as many of those are
focused on ABCs in the first place.

It's easy to notice a submodule when reading docs on the internet, but it's
hard to figure out what the correct module is to import when hanging out at
a basic REPL. Flat is better than nested and all that.

* Yes, I know, these are not concrete implementations of types... I find
>> it a little confusing to describe.
>>
>
> It's a possibility. Feel free to comment on the issue if you want to
> discuss this further.
>
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