[Nix-dev] [***SPAM***] Thoughts on the Nix model

[Daniel Hlynskyi]

Nice way to establish "declarativeness" of Nix expressions is to integrate
OWL (or any other description logic based language) into Nix such that we
can do (lossy) translation nixpkgs -> .owl and query results with existing
OWL tooling.

The list of queries Nix itself does not support is a first thing to do in
this case

2015-09-14 14:40 GMT+03:00 Kosyrev Serge <_deepfire at feelingofgreen.ru>:

> Good day folks!
>
> The growth in popularity Nixpkgs enjoys, as exemplified by the continuing
> uptake in the unmerged pull requests, is the evidence that directs us away
> from the kind of issues I feel like raising in this message.
>
> Yet, after a year and a half of my personal experience of using and
> occasionally contributing to NixOS, it's becoming hard to dismiss them.
>
> First, let me start with an empathic agreement that the ideas underlying
> NixOS make it almost unique in the fundamental soundness of its system
> composition and configuration management.
>
> Nothing, however, comes for free, and the operational complexity of
> traditional Linux distributions shifts into an unparallelled descriptive
> complexity in the support infrastructure of NixOS [1].
>
>                       -   -   -
>
> But, what is the evidence for this descriptive complexity?
>
> The simple fact that Turing-complete code is used to describe
> /everything/.
>
> One could say, of course, that the leaf 'default.nix' files are mostly
> declarative.
>
> The response is that, of course, this is an observation the
> meaningfulness of which can be judged by the awful state of the tools
> that are supposed to query the package database.
>
> With all due respect, in comparison with traditional distributions,
> they are either atrocious or non-existent.
>
> And I don't mean only user-facing tools here, but mostly tools to
> support the developer -- things like the 'dpkg-*' suite, for
> example.
>
> We all know about the hard limits to program analysis, and of course the
> retreat used by Nix to support these tools, is an introduction of
> regularity that is barely sufficient to sustain a pretense of automatic
> processing outside of the default mode of execution -- derivation.
>
> Let's not fool ourselves -- with the exception of the core path of the
> Nix deriver, which they were designed to support, the 'default.nix'
> files are perpetually hovering on being barely declarative enough for
> the meager assortment of other tooling to work.
>
>                       -   -   -
>
> Another thing that could be said, is that there is no need for
> declarativity at all, since the code can be executed, and the
> returned derivations can be queried for the desired properties.
>
> Unfortunately, limiting analysis to execution (if one can be excused for
> uttering such blasphemy) has the following undesirable properties, among
> others:
>
>   - it makes validation nigh impossible, for example due to the returned
>     data structures /themselves/ containing executable functions
>
>   - crucially, it leaves no choice but to use Nix for writing tools
>     manipulating the what-ought-to-be-declarations
>
>   - deriving from the above, it also means the analysis is going to
>     be /slow/, at least with the current implementation of Nix
>
>   - the attempts to hide this slowness already results in warts,
>     like haskellPackages being a separate namespace
>
> The second point is, without question, the gravest, because while Nix
> might be an adequate language for expressing derivations, I think it's
> in unarguable that it's ill-suited for writing tooling.
>
> And yet, the meat of the information contained in the "package database"
> is either unavailable, or has restricted availability to anything outside
> Nix.
>
> In my perception, this situation can't be good in the long term.
>
>
> --
> 1. Don't get me wrong -- one could say that in comparison, the traditional
> distributions mostly don't even attempt to formalize their composition.
> NixOS is clearly without precedent here.
> --
> с уважениeм / respectfully,
> Косырев Серёга
> --
> “And those who were seen dancing were thought to be insane
> by those who could not hear the music.”
> – Friedrich Wilhelm Nietzsche
> _______________________________________________
> nix-dev mailing list
> nix-dev at lists.science.uu.nl
> http://lists.science.uu.nl/mailman/listinfo/nix-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.science.uu.nl/pipermail/nix-dev/attachments/20150921/7b3edc48/attachment.html