shell.nix

 { nixpkgs ? import <nixpkgs>
  {}
  # { overlays = [(self: super: {gsl = super.gsl.overrideAttrs (o: {CFLAGS = "-DDEBUG";});})]; }
, compiler ? "ghc822"
, doBenchmark ? false }:

let

  inherit (nixpkgs) pkgs;

f = { mkDerivation, ad, array, base, bytestring, cassava, containers
    , datasets, diagrams-lib, diagrams-rasterific, foldl, Frames, ghc-prim
    , hmatrix, hmatrix-gsl
    , inline-r, julia, lens, mtl, pipes, plots, random-fu, R, random-source
    , stdenv, template-haskell, text, typelits-witnesses, vector, vinyl }:

mkDerivation {
  pname = "variational";
  version = "0.1.0.0";
  src = ./.;
  isLibrary = false;
  isExecutable = true;
  executableHaskellDepends = [
    ad
    array
    base
    bytestring
    cassava
    containers
    datasets
    diagrams-lib
    diagrams-rasterific
    foldl
    Frames
    ghc-prim
    hmatrix
    hmatrix-gsl
    inline-r
    lens
    mtl
    pipes
    plots
    random-fu
    random-source
    template-haskell
    text
    typelits-witnesses
    vector
    vinyl
  ];
  executableSystemDepends = [
    patched-gsl
    julia
    R
    pkgs.rPackages.anytime
    pkgs.rPackages.ggplot2
    pkgs.rPackages.maptools
    pkgs.rPackages.reshape2
    pkgs.rPackages.rgeos
    pkgs.rPackages.rgdal
    pkgs.rPackages.rstan ];
  license = stdenv.lib.licenses.bsd3;
};

haskellPackages = if compiler == "default"
  then pkgs.haskellPackages
  else pkgs.haskell.packages.${compiler};

variant = if doBenchmark then pkgs.haskell.lib.doBenchmark else pkgs.lib.id;

patched-gsl = pkgs.gsl.overrideAttrs (oldAttrs: rec {
  src = /Users/dom/gsl;
  version = "2.6";
  name = "gsl-${version}";
  doCheck = false;
  CFLAGS = "-DDEBUG -O2";
});

patched-hmatrix = pkgs.haskellPackages.hmatrix.overrideAttrs (oldAttrs: rec {
  src = nixpkgs.fetchgit {
    url = git://github.com/albertoruiz/hmatrix;
    rev = "d83b17190029c11e3ab8b504e5cdc917f5863120";
    sha256 = "11wr59wg21rky59j3kkd3ba6aqns9gkh0r1fnhwhn3fp7zfhanqn";
  };
  postUnpack = ''
    sourceRoot=''${sourceRoot}/packages/base
    echo Source root reset to ''${sourceRoot}
  '';
});

patched-hmatrix-gsl = pkgs.haskellPackages.hmatrix-gsl.overrideAttrs (oldAttrs: rec {
  src = nixpkgs.fetchgit {
    url = git://github.com/albertoruiz/hmatrix;
    rev = "d83b17190029c11e3ab8b504e5cdc917f5863120";
    sha256 = "11wr59wg21rky59j3kkd3ba6aqns9gkh0r1fnhwhn3fp7zfhanqn";
  };
  postUnpack = ''
    sourceRoot=''${sourceRoot}/packages/gsl
    echo Source root reset to ''${sourceRoot}
  '';
  libraryPkgconfigDepends = [patched-gsl];
});

drv = variant (haskellPackages.callPackage f {
  hmatrix = patched-hmatrix;
  hmatrix-gsl = patched-hmatrix-gsl; });

in

  if pkgs.lib.inNixShell then drv.env else drv