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dhall-lang / dhall-haskell

Maintainable configuration files
https://dhall-lang.org/
BSD 3-Clause "New" or "Revised" License
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What important thing needs to be solved in HNix to allow better Dhall integration #1678

Closed Anton-Latukha closed 4 years ago

Anton-Latukha commented 4 years ago

I am kinda in search, what task to pick next in HNix.

What you consider the shortcoming of the HNix that can&should be solved?

sjakobi commented 4 years ago

Thanks for asking! Personally, I don't have any feature requests, but I would love to see a release that is compatible with the latest prettyprinter and GHC. That would greatly simplify building and packaging dhall-nix.

BTW I just attempted building hnix from Hackage and got this:

Nix/Expr/Types.hs:76:3: error:
    ‘showsPrec1’ is not a (visible) method of class ‘Show1’
   |
76 |   showsPrec1 = showsPrec
   |   ^^^^^^^^^^
Gabriella439 commented 4 years ago

@Anton-Latukha: The number one thing hnix can improve upon would not be a specific feature, but rather just a regular release cadence. The last release to Hackage was almost a year ago

Anton-Latukha commented 4 years ago

@Gabriel439 @sjakobi

Chatted with John, he basically stated that HNix does not build for all the conditions he requires.

I would investigate that and tend to it, and then would form a release.

Gabriella439 commented 4 years ago

@Anton-Latukha: While you are looking for ways to improve hnix, codifying those supported platforms/environments in CI would help prevent this from recurring in the future. For example, for Dhall we use CI to ensure that no pull request is merged that breaks any supported platform or any supported GHC.

Anton-Latukha commented 4 years ago

@Gabriel439

I know, I know.

It can be quite hard to squeeze into free Travis norms what is needed for Haskell, but that is understandable for free.

Especially when Travis, AFAIK, failed miserably some times. Hope they fixed their networking issues for nodes.

Overall, yes, property testing and CI.

What CI would you recommend currently for free Haskell projects, I see you use both Travis and Appveyor.

Gabriella439 commented 4 years ago

@Anton-Latukha: I think it depends on what John needed to support before releasing. It's not clear to me if that means operating systems, GHC versions, GHCJS, etc.

Anton-Latukha commented 4 years ago

@Gabriel439

Of course - I just asked a pretty stupid general question.

Gabriella439 commented 4 years ago

@Anton-Latukha: Probably the biggest constraint is whether or not CI needs to test Windows or OS X, since build machines for those are harder to come by. We currently use AppVeyor for Windows builds and Travis for OS X builds since they are free. For Linux you can basically use any CI provider, but in this case I pay for a Linode VM which I use to host all Dhall-related infrastructure (i.e. all of the *.dhall-lang.org domains), so I reuse that to host Hydra for Nix-related CI so that I can use more parallelism and more efficient caching to test a wider range of GHC versions on a budget.

For testing OS X and Windows platforms we use stack. The main reason we don't use Nix for either platform is that Nix only supports building release binaries on Linux (and even then it's still experimental).

So the basic summary I can give is:

Also, if you ever can pay for your own NixOS VM and you want to reuse the setup I built, you can find the NixOS configuration for dhall-lang.org here:

https://github.com/dhall-lang/dhall-lang/tree/master/nixops

Anton-Latukha commented 4 years ago

Thank you. Very to the point. This information worth a dedicated article (blog post) in itself, but may not worth an effort of the high-quality article, as it is the current state of affairs.

Gabriella439 commented 4 years ago

@Anton-Latukha: You're welcome! 🙂

Anton-Latukha commented 4 years ago

@Gabriel439 Would you allow me add https://github.com/dhall-lang/dhall-haskell/issues/1678#issuecomment-592960057 as your quote in my docs?

Gabriella439 commented 4 years ago

@Anton-Latukha: Yeah, definitely! 🙂

Anton-Latukha commented 4 years ago

@Gabriel439 Thank you, here is where the quote is used https://blog.latukha.com/haskell-notes#org05bb15e Page is large, it would load for a couple of secs and then center on the quote. Also the Org-mode HTML export changes the anchor IDs around, so on next publish it would be other URL ID.

Also there is a new HNix release!