trying to make nix expressions

default.nix

@@ -0,0 +1,21 @@
+{ compiler ? "ghc822" }:
+  let
+   config = {
+     packageOverrides = pkgs: with pkgs.haskell.lib; {
+       haskell = pkgs.haskell // {
+         packages = pkgs.haskell.packages // {
+            ${compiler} = pkgs.haskell.packages.${compiler}.override {
+              overrides = self: super: rec {
+                nanovg = 
+                  buildStrictly (self.callPackage ../nanovg-hs/nanovg.nix {});
+              };
+           };
+         };
+      };
+   };
+};
+in
+  let
+    pkgs = import <nixpkgs> { inherit config; };
+    nanovg = pkgs.haskell.packages.${compiler}.nanovg;
+in { inherit nanovg; }

haskelloids.cabal

@@ -51,7 +51,8 @@ executable haskelloids
   -- .hs or .lhs file containing the Main module.
   main-is:             Main.hs
   ghc-options:         -Wall
-  extra-libraries:   GLEW
+  extra-libraries:     GLEW
+  pkgconfig-depends:   glew
   
   -- Modules included in this executable, other than Main.
   other-modules:      Types 

haskelloids.nix

@@ -0,0 +1,17 @@
+{ mkDerivation, affection, base, containers, glew, linear
+, nanovg, OpenGL, random, sdl2, stdenv, stm
+}:
+mkDerivation {
+  pname = "haskelloids";
+  version = "0.0.0.1";
+  src = ./.;
+  isLibrary = false;
+  isExecutable = true;
+  executableHaskellDepends = [
+    affection base containers linear nanovg OpenGL random sdl2 stm
+  ];
+  executableSystemDepends = [ glew ];
+  executablePkgconfigDepends = [ glew sdl2 ];
+  description = "A little game using Affection";
+  license = stdenv.lib.licenses.gpl3;
+}

shell.nix

@@ -0,0 +1,39 @@
+{ nixpkgs ? import <nixpkgs> {}
+, compiler ? "default"
+, doBenchmark ? false
+, nanovg
+}:
+
+let
+
+  inherit (nixpkgs) pkgs;
+
+  f = { mkDerivation, affection, base, containers, glew
+      , linear, nanovg, OpenGL, random, sdl2, stdenv, stm
+      }:
+      mkDerivation {
+        pname = "haskelloids";
+        version = "0.0.0.1";
+        src = ./.;
+        isLibrary = false;
+        isExecutable = true;
+        executableHaskellDepends = [
+          affection base containers linear nanovg OpenGL random sdl2 stm
+        ];
+        executableSystemDepends = [ glew ];
+        executablePkgconfigDepends = [ glew ];
+        description = "A little game using Affection";
+        license = stdenv.lib.licenses.gpl3;
+      };
+
+  haskellPackages = if compiler == "default"
+                       then pkgs.haskellPackages
+                       else pkgs.haskell.packages.${compiler};
+
+  variant = if doBenchmark then pkgs.haskell.lib.doBenchmark else pkgs.lib.id;
+
+  drv = variant (haskellPackages.callPackage f {});
+
+in
+
+  if pkgs.lib.inNixShell then drv.env else drv