Re: how to write services (was: Re: Teams)

[Blake Shaw <blake@sweatshoppe.org>]

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Thanks for the feedback, abelian groups are a good example because so many
groups are abelian (fields etc).

But, perhaps it's just getting late and the matters are now & the details
are slipping my mind, but im starting to realize im unsure of many examples
of file-like objects that aren't a file? The email where you responded re:
packages was cut short, but it seemed to be that you were saying that
record-types *aren't* file-like, when I had thought they are; I thought
anything with simple means of serialization could be considered file-like,
and that pseudofiles (/devs, /procs, etc) were also in the file-like
category (which is apparently a misnomer on my part).

Would anyone care to share an explanation of what is/is not a file-like
object in Guix? Are fluids not considered file-like? I had thought that
would be a use case where this geneticity becomes important.

I remember when I first encountered gexps I thought, as FLOs didn't seem to
be files, they were either records or fluids. It took me a good while to
realize a file-like object is usually just a file, haha

On Thu, Jun 16, 2022, 05:28 Maxime Devos <maximedevos@telenet.be> wrote:

> Blake Shaw schreef op wo 15-06-2022 om 21:40 [+0000]:
> > On the contrary, lets say I'm writing an intro book on CT. If I'm
> > demonstrating something trivial, say the initial object, I'm not
> > going to refer to it as "an initial-like object" for the sake of
> > generality.
>
> Neither does Guix?  If you're in a context where only the basic object
> (in this case, your demonstration the initial object) is used, just
> talk about the basic object.  But in a later section where you
> generalize things to ‘initial-like objects’ (whatever that would be in
> CT, I don't know any CT), you talk about ‘initial-like objects’, not
> ‘initial object and initial-like objects’.
>
> For an example from another domain, consider groups in algebra.
> In group theory, we have e.g. the fundamental theorem on homomorphisms.
> Wikipedia formulates this as:
>
> Given two groups G and H and a group homomorphism f : G → H, let K be a
> normal subgroup in G and φ the natural surjective homomorphism G → G/K
> (where G/K is the quotient group of G by K). If K is a subset of ker(f)
> then there exists a unique homomorphism h: G/K → H such that f = h∘φ.
>
> An equivalent statement could be made by replacing ‘given a group’ by
> ‘given an Abelian group or a group’:
>
> Given two Abelian groups or groups G and H and a group homomorphism f :
> G → H, let K be an Abelian normal subgroup or normal subgroup in G and
> φ the natural surjective homomorphism G → G/K (where G/K is the
> quotient group of G by K). If K is a subset of ker(f) then there exists
> a unique homomorphism h: G/K → H such that f = h∘φ.’
>
> But why do such a pointless thing, wouldn't just talking about groups
> instead of ‘Abelian groups or groups’ be much simpler?
>
> TBC: here ‘file-like object’ ≃ ‘group’ and ‘file’ = ‘Abelian group’.
>
> Greetings,
> Maxime.
>

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