Hi Volker,
On 2014-03-09, Volker Braun <vbraun.n...@gmail.com> wrote:
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>
> On Sunday, March 9, 2014 2:16:51 PM UTC, Simon King wrote:
>>
>> class Cs(Category):
>> class Finite(CategoryWithAxiom):
>> class ParentClass:
>> def some_method(self):
>> return "I am a finite c"
>> is also (I think) *sufficiently* explicit about Cs.Finite() being a
>> sub-category of Cs(), defined by the axiom Finite.
>>
>
> This snippet defines a finite axiom that is different from the finite axiom
> for sets, and your parents will not have a "is_finite()" method.
The snippet was supposed to be a continuation of the first snipped,
which stated that Cs() is a sub-category of Sets(). Sorry for not being
clear.
> Really, the whole subclass-as-axiom magic is just an attempt at syntactic
> sugar. The only thing that matters is that Cs().Finite() returns an
> instance of the the axiom. There are various functionally equivalent ways
> to implement it. There is yet another syntax to achieve the same end,
> namely Cs().with_axiom("Finite"). Except for the strings I would be much
> happier with that since it doesn't require an open-ended list of magic
> attribute names for axioms.
OK, that is the syntax that you want for *using* axioms: Not Cs.Finite() or
Cs().Finite(), but Cs.with_axiom("Finite") or even better
Cs.with_axiom(axioms.Finite). Fair enough.
But your answer is orthogonal to what I was asking you: What syntax to you
suggest for *implementing* axioms? Do you think stating that Cs() is a
subcategory of Sets() is not good enough for having Cs().Finite() being
a sub-category of Sets().Finite()? What else is there to code, in your
opinion?
Best regards,
Simon
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