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 still causes network traffic. Run the utility
with --help to see the complete list of supported command-line flags.
Detailed instructions on how to use those generated files with Nix can be found at
https://nixos.org/nixpkgs/manual/#how-to-create-nix-builds-for-your-own-private-haskell-packages.
cabal2nix can also build derivations for projects from other sources than
Hackage. You only need to provide a URI that points to a cabal project. The
most common use-case 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 repository types:
- directory
- source archive (zip, tar.gz, ...) from http or https URL or local file.
- git, mercurial, svn or bazaar repository