[Python-ideas] OrderedCounter and OrderedDefaultDict

[Jonathan Slenders]

Just want to say that I'm happy to see that lately the disadvantages of
inheritance (which are already known for a very long time) are getting more
attention.
It's not bad by definition, but there's so much truth in Sandy her talk and
I think for many Python projects, we went way too far into "abusing"
inheritance.
Actually, it's a bit unfortunate that we made inheritance so user friendly
and powerful in Python that for many people it became the logical way to
extend or reuse some code.

Jonathan







2015-10-21 19:41 GMT+02:00 Sven R. Kunze <srkunze at mail.de>:

> On 21.10.2015 00:50, Chris Angelico wrote:
>
> She recommends a massive superclass that's capable of any form of injection
>
>
> Nope. She does not.
>
> The "superclass" is not "massive" at all. It is even slimmer as orthogonal
> aspects are refactored out into separate entities. In fact, it makes it
> even easier to test and maintain these separate aspects (the core dev
> should be interested in that). Furthermore, it's, of course, up to debate
> which aspects should be injectable and which are not.
>
>
> Just imagine, I would need to use several orderings and/or a default value
> for missing keys:
>
> normal_dict = dict()
> ordered_dict = dict(order=dict.order_by_insert)
> sorted_dict = dict(order=sorted)
> sorted_default_dict = dict(order=sorted, default=int)
>
>
> How many subclasses am I supposed to write, maintain and upgrade (in case
> Guido rewrites his precious dict implementation)? I would even allege that
> for sufficiently large teams and projects, there are *multiple*
> implementations with the same intent.
>
>
> Please, no.
>
>
> Best,
> Sven
>
>
> PS: the instances above are real-world examples, I remember requiring
> during the course of the last year.
>
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