“Styx: there is no looking back.”
Styx is a convenient wrapper around cabal2nix, nix-shell and
cabal sandbox.
- get nix: https://nixos.org/nix/
- install the prerequisites (cabal2nix and cabal)
nix-env -f "<nixpkgs>" -iA haskellPackages.cabal2nix nix-env -f "<nixpkgs>" -iA haskellPackages.cabal-install
- install styx:
nix-env -f "<nixpkgs>" -iA haskellPackages.styx
In a directory of your choice, create a styx.yaml file like so:
# List first the packages that you edit locally and want compiled "all the time", by cabal:
local-packages:
my-main-package: # package name
location: . # location on your disk
my-local-dep: # package name
location: dep # location on your disk
# Optional: list patched or cutting edge packages that you depend on.
# These will be compiled only once, by nix.
source-deps:
mtl:
location: https://github.com/mrawesome/awsm-patched-version-of-mtl.git
# If you want you can add other haskell nix packages to depend on.
# Normally this is not necessary, because nix will track the dependencies on its own.
# Thus this section is mostly useful for throw-away projects which do not have a cabal file.
nix-deps:
- criterion
- gasp
- lens
- statistics
# In case you depend on other non-haskell tools or libs.
non-haskell-deps:
- z3
# Optionally, one can ask for a specific version of nixpkgs:
nixpkgs:
commit: 8ef3eaeb4e531929ec29a880cb4c67f790e5eb70
sha256: 4d2fae900d2d99ea294f4f412289af77152ac21d7b2e9ff23581ef11ea00831f
# Optionally, one can ask for a specific version of ghc known by nixpkgs
default-compiler: ghc801
Then, the command
styx configurewill create one nix file for each external package, a suitable
shell.nix, and a sandbox with sources for every local-package.
You can then access the sandbox, inside the nix shell, like so:
nix-shell .styx/shell.nix --run "cabal ..."
Styx provides a couple of convenience commands:
$ styx build # runs cabal install in the sandbox
$ styx repl # runs cabal repl in the sandbox
$ styx exec <cmd> # runs cabal exec in the sandbox