The garn devlog

[jkarni]

garn is an effort to give a Typescript-based alternative to Nix, and an easier CLI interface. It’s been discussed before, but development is happening very quickly, so I thought I’d create a devlog thread here. If you don’t want to hear more about it, you can mute it, and if you do, you can follow it.

[jkarni]

Version 0.0.18 has been released.

Highlights:

• A new edit command. A lot of the power of garn, where it almost feels like garn.ts files write themselves, comes from IDE integration. Because we use Deno instead of the more traditional Node, a lot of people don’t have their editors set up fully yet. We previously had a garn Executable, editGarnConfig, that you could expose for users. But that had problems, such as being less discoverable, and breaking if your garn.ts file was broken. Now, we made editing a built-in. This means you can just run garn edit and you’ll open garn.ts on an editor configured with autocompletion and other features. Currently the only editor option is VSCodium, but we’re very open to PRs - see this file.
• garn no longer ignores untracked files. Previously you’d get confusing errors about files missing if you hadn’t yet git added them. This was because (controversially) Nix behaved similarly. We submitted a patch to Nix, and made garn already use that patch.
• Multiple executables in Haskell projects. Previously you needed exactly one executable, which was quite arbitrary and confusing. Now any number of executables, including none, is supported.
• Make garn init add executables to Haskell projects based on the executables listed in the cabal file.
• Overriding Haskell dependency versions. Now you can write, for example:

export const project = haskell.mkHaskellProject({
  description: "",
  compiler: "ghc94",
  src: ".",
  executables: ["foo"],
  // This is new
  overrideDependencies: {
    "string-conversions": "0.3.0.3",
  },
})

And you get the correponding version from Hackage, rather than the default one from the package set. This is as easy as Stack, but with the power of Nix.

• garn enter top-level Environments. Previously Environments, unlike everything else, didn’t really work at the top-level, and instead had to be part of a Project.

[jkarni]

And a new release, with the ability to easily import local and remote flakes. E.g.:

const flake = garn.importFromGithub({
  repo: "martinvonz/jj",
  revOrRef: "v0.11.0",
});

export const devEnv = garn.emptyEnvironment.withDevTools([
  flake.getPackage("default"),
]);

This should help incrementally moving over if that’s your thing.

Full blog post: garnix | the nix CI

[rjpc]

Seems interesting. The CLI is written in TS, yes? How do you like TS for CLI work?

[jkarni]

It’s actually written in Haskell! The CLI has to be a different program than the garn.ts file users write (since, among other reasons, otherwise syntax errors in the file would leave you with a completely unusable garn; and things like garn init wouldn’t be available). Mostly for reasons of familiarity, we wrote it in Haskell. But it kind of really is just the CLI - all the more substantive logic is in TS.