cabal2nix

Convert Cabal files into Nix build instructions. https://github.com/nixos/cabal2nix#readme

LTS Haskell 8.20:2.0.4
Stackage Nightly 2017-06-28:2.2.1
Latest on Hackage:2.2.1
BSD3 licensed by Peter Simons, Andres Loeh, Benno Fünfstück, Mateusz Kowalczyk, Michael Alan Dorman, Mathijs Kwik, Shea Levy, Dmitry Malikov, Eric Seidel, Hamish Mackenzie, Nikolay Amiantov, Aycan iRiCAN, Bryan Gardiner, Joe Hermaszewski, John Wiegley, Philipp Hausmann, Spencer Janssen, Tom Hunger, William Casarin, koral, Adam Vogt, Alexey Shmalko, Corey O'Connor, Cray Elliott, Felix Kunzmann, Gabriel Ebner, Gergely Risko, Jacob Mitchell, Joachim Fasting, John Albietz, John Chee, Jussi Maki, Mark Laws, Mark Wotton, Matthew Stewart, Matvey Aksenov, Nicolas Rolland, Oliver Charles, Pascal Wittmann, Patrick John Wheeler, Profpatsch, Raymond Gauthier, Renzo Carbonara, Rodney Lorrimar, Sibi, Tanner Doshier, Viktar Basharymau, danbst, karsten gebbert, laMudri, Александр Цамутали

Cabal2nix

cabal2nix converts a single Cabal file into a single Nix build expression. For example:

$ cabal2nix cabal://mtl
{ mkDerivation, base, stdenv, transformers }:
mkDerivation {
  pname = "mtl";
  version = "2.2.1";
  sha256 = "1icdbj2rshzn0m1zz5wa7v3xvkf6qw811p4s7jgqwvx1ydwrvrfa";
  libraryHaskellDepends = [ base transformers ];
  homepage = "http://github.com/ekmett/mtl";
  description = "Monad classes, using functional dependencies";
  license = stdenv.lib.licenses.bsd3;
}

Cabal files can be referred to using the magic URL cabal://NAME-VERSION, which will automatically download the file from Hackage. Alternatively, a direct http://host/path/pkg.cabal URL can be provided, as well as a file:///local/path/pkg.cabal URI that doesn't depend on network access. However, if the source hash is not already in cabal2nix's cache or provided using the --sha256 option, cabal2nix still needs to download the source code to compute the hash, which obviously still causes network traffic. Run the utility with --help to see the complete list of supported command line flags.

Detailed instructions how to use those generated files with Nix can be found at http://nixos.org/nixpkgs/manual/#users-guide-to-the-haskell-infrastructure.

cabal2nix can also build derivations for projects from other sources than hackage. You only need to provide an URI that points to a cabal project. The most common usecase for this is probably to generate a derivation for a project on the local file system:

$ cabal get mtl-2.2.1 && cd mtl-2.2.1
$ cabal2nix .
{ mkDerivation, base, stdenv, transformers }:
mkDerivation {
  pname = "mtl";
  version = "2.2.1";
  src = ./.;
  libraryHaskellDepends = [ base transformers ];
  homepage = "http://github.com/ekmett/mtl";
  description = "Monad classes, using functional dependencies";
  license = stdenv.lib.licenses.bsd3;
}

This derivation will not fetch from hackage, but instead use the directory which contains the derivation as the source repository.

cabal2nix currently supports the following respository types:

  • directory
  • source archive (zip, tar.gz, ...) from http or https URL or local file.
  • git, mercurial, svn or bazaar repository
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