Unison-nix Alternatives

unison-nix reviews and mentions

• Unison Cloud
  7 projects | news.ycombinator.com | 7 Feb 2024

  I use both Unison and Nix (and I work on Unison Cloud).

  The "oh-so-good" aspect that comes from content-addressed dependencies is definitely there. I've spent a lot of time debugging runtime issues on the JVM because two libraries that I depend on disagree on what version of a common dependency should be on my classpath. This is not something you ever experience with Unison. In the runtime every term and type are identified by their hashes, so there's no (realistic) way that names can collide.

  Otherwise, Unison and Nix feel pretty different to me. Nix is generally a build-time language for arbitrary runtimes, while Unison is a general purpose language for a specific runtime.

  Nix takes on the really ambitious goal of wrangling ancient projects built with Makefiles and ambient environments into deterministic builds. Through the heroic effort of derivation authors, they've managed to make it work. But it requires those maintainers to do lots of careful manual tracking of dependencies, pre-build source patches, overriding build steps, etc.

  Unison takes a much more constrained approach: if we start with a language that is content-addressed at its core and keep running with this idea, where do we end up? One nice outcome of this is that you never need to manually track dependency versions, hashes, etc; the language does that for you.

  The "tough" part is also there, but feels different. To me the Nix expression language is straightforward, but I find it difficult to wrap my head around nontrivial derivations. To answer questions like "what attributes and build steps can/should I override" I feel like I have to dig through the layers of the implementation. In Unison a powerful static type system and UIs (both local and Unison Share) that support clicking through to any term/type make it easier for me to digest code. The "tough" parts of Unison generally stem from the young ecosystem: fewer existing libraries, a codebase manager that is under active development and not nearly as stable as git, etc.

  If nothing else Unison is worth a try just because it is so different than most other languages/ecosystems.

  PS if you are interested in usin Nix to install the Unison codebase manager or to package a program written in Unison these repos might be useful (disclaimer I'm ceedubs):

  https://github.com/ceedubs/unison-nix/