Haskell + Emacs + LSP + Nix

cabal.project

packages: ./*.cabal
jobs: $ncpus
optimization: 2
executable-stripping: True
documentation: True
haddock-html-location: https://hackage.haskell.org/packages/archive/$pkg/$version/doc/html
haddock-hyperlink-source: true

default.nix

{ sources ? import ./nix/sources.nix
, haskellNix ? import sources."haskell.nix" {}
, nixpkgsSrc ? haskellNix.sources.nixpkgs-2009
, compiler ? "ghc8102" }:

let
  overlays = haskellNix.nixpkgsArgs.overlays;
  pkgs = import nixpkgsSrc {
    inherit overlays;
    inherit (haskellNix.nixpkgsArgs) config;
  };

in pkgs.haskell-nix.cabalProject {
  compiler-nix-name = compiler;
  src = pkgs.haskell-nix.haskellLib.cleanGit {
    name = "your-project-name";
    src = ./.;
  };
}

hie.yaml

cradle:
  multi:
    - path: ./Setup.hs
      config:
        cradle:
          direct:
            arguments:
              - "-package Cabal"
              - "-package base"
    - path: "./"
      config:
        cradle:
          cabal:
            - path: "src"
              component: "lib:your-project-name"
            - path: "app/Main.hs"
              component: "your-project-name:exe:example"
            - path: "test"
              component: "your-project-name:test:example-test"

nix.conf

substituters = https://cache.nixos.org https://nix-tools.cachix.org https://hercules-ci.cachix.org https://hydra.iohk.io https://cache.dhall-lang.org https://dhall.cachix.org https://cache.nixos.org/ https://srid.cachix.org https://nix-community.cachix.org
trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= nix-tools.cachix.org-1:ebBEBZLogLxcCvipq2MTvuHlP7ZRdkazFSQsbs0Px1A= hercules-ci.cachix.org-1:ZZeDl9Va+xe9j+KqdzoBZMFJHVQ42Uu/c/1/KMC5Lw0= hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= cache.dhall-lang.org:I9/H18WHd60olG5GsIjolp7CtepSgJmM2CsO813VTmM= dhall.cachix.org-1:8laGciue2JBwD49ICFtg+cIF8ddDaW7OFBjDb/dHEAo= srid.cachix.org-1:MTQ6ksbfz3LBMmjyPh0PLmos+1x+CdtJxA/J2W+PQxI= nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs

shell.nix

let hsPkgs = import ./default.nix { };
in hsPkgs.shellFor {
  packages = ps: [ ps.your-project-name ];
  withHoogle = true;
  tools = import ./tools.nix;
}

tools.nix

{
  cabal = "3.2.0.0";
  haskell-language-server = "latest";
  hlint = "3.2.3";
  fourmolu = "0.3.0.0";
  ormolu = "0.1.4.1";
  weeder = "2.1.2";
}