unison-nix

Nix support for the Unison programming language

usage

NOTE: If you don't already have Nix installed, follow the instructions on the Nix site.

install Unison code manager

If your version of Nix supports Nix flakes:

nix profile install github:ceedubs/unison-nix#ucm-bin

Use from home-manager:

In your home-manager's flake.nix, reference this repository under inputs, e.g.:

unison-lang = {
  url = "github:ceedubs/unison-nix";
  inputs.nixpkgs.follows = "nixpkgs";
};

then add the unison-lang overlay:

pkgs = import nixpkgs {
  inherit system;
  overlays = [ unison-lang.overlay ];
};

Finally, in your home.nix, just add the unison-ucm package as you normally would.

An example is available here.

Older versions of Nix:

nix-env -iA unison-ucm -f https://github.com/ceedubs/unison-nix/archive/trunk.tar.gz

try out Unison without installing it to your PATH/Nix profile

If your version of Nix supports Nix flakes:

nix run github:ceedubs/unison-nix#ucm-bin

Older versions of Nix:

nix-build https://github.com/ceedubs/unison-nix/archive/trunk.tar.gz -A unison-ucm

This will create a symlink named result in your current directory. Now run:

./result/bin/ucm

Once you are done trying out Unison you can rm ./result.

available packages/tools

• ucm-bin: a binary release of the Unison code manager
  • This is named unison-ucm in the overlay and for older versions of Nix (pre-flakes)
• ucm: a release of the Unison code manager built from source (without some of the niceties provided by ucm-bin)
• vim-unison: a vim plugin providing syntax highlighting for Unison files
  • This is provided as vimPlugins.vim-unison in the overlay
• VS Code extensions
  • unison-lang.unison – the official extension from the Unison team, provides syntax highlighting and LSP support
  • TomSherman.unison-ui – adds a codebase explorer sidebar
• overlay: A nixpkgs overlay that adds the Unison packages in the relevant places (ex: vim-unison in vimPlugins.vim-unison)
• buildShareProject a function for turning functions in a Unison Share project into executable derivations.
  • See unison-nix-snake for an example.
  • See nix/build-share-project.nix for documentation.
• buildFromTranscript a lower-level function for turning a Unison transcript into an executable derivation.
  • See nix/build-from-transcript.nix for documentation.

In the future this repository would be a natural home for derivations for other Unison tools.

NOTE: the unison github repo repo has a flake.nix that you can use with nix develop to get an environment with the expected versions of stack, ormolu, etc.

FAQ

Fabricated/Anticipated Questions

Why don't these derivations live in nixpkgs?

The nixpkgs repository was the original home of Unison Nix dervations, but Unison is evolving quickly and getting Unison updates merged into nixpkgs turned out to be a bottleneck in getting these new features and bug fixes out to Unison users.