Make nix develop work

README.md

@@ -3,7 +3,7 @@
 ## Building the executable
 
 ```
-$ nix run
+$ nix build
 ```
 
 ## Building the Docker image
@@ -18,6 +18,12 @@ $ docker load < $(nix-build nix/docker-image.nix)
 Includes Stack, `haskell-language-server`, `gen-hie` etc.
 
 ```
-# TODO
-$ nix-shell
+nix develop
+```
+
+## Running Stack and GHC
+
+```
+nix run .#stack
+nix run .#ghc
 ```

flake.nix

@@ -12,58 +12,64 @@
       pkgs = nixpkgs.legacyPackages.x86_64-linux.extend overlay;
       haskellPackages = pkgs.haskell.packages."${settings.ghc}";
 
+      ghc = haskellPackages.ghcWithPackages haskellDeps;
       stack = pkgs.stdenv.mkDerivation {
-        pname = "stack";
-        version = "0";
+        name = "stack";
         dontUnpack = true;
         dontConfigure = true;
         dontBuild = true;
         nativeBuildInputs = [ pkgs.makeWrapper ];
         installPhase = ''
           makeWrapper ${pkgs.stack}/bin/stack $out/bin/stack \
-            --add-flags '--no-nix --no-install-ghc'
+            --prefix PATH : ${ghc}/bin \
+            --add-flags '--no-nix --system-ghc --no-install-ghc'
         '';
       };
+      utoy' =
+        { mkDerivation }:
+        mkDerivation {
+          version = "0.5";
+          pname = "utoy";
+          license = pkgs.lib.licenses.mit;
+          src =
+            let
+              buildFiles = [
+                ./LICENSE
+                ./utoy.cabal
+                ./Setup.hs
+                ./app
+                ./src
+                ./static
+                ./test
+              ];
+            in
+              pkgs.lib.sources.cleanSourceWith {
+                src = ./.;
+                filter = path: _type: pkgs.lib.any (prefix: pkgs.lib.hasPrefix (toString prefix) path) buildFiles;
+              };
+
+          libraryHaskellDepends = haskellDeps haskellPackages;
+        };
+        utoy = pkgs.haskell.lib.justStaticExecutables (haskellPackages.callPackage utoy' {});
     in {
-      packages.x86_64-linux.stack = stack;
-      packages.x86_64-linux.utoy =
-        let
-          utoy =
-            { mkDerivation }:
-            mkDerivation {
-              version = "0.5";
-              pname = "utoy";
-              license = pkgs.lib.licenses.mit;
-              src =
-                let
-                  buildFiles = [
-                    ./LICENSE
-                    ./utoy.cabal
-                    ./Setup.hs
-                    ./app
-                    ./src
-                    ./static
-                    ./test
-                  ];
-                in
-                  pkgs.lib.sources.cleanSourceWith {
-                    src = ./.;
-                    filter = path: _type: pkgs.lib.any (prefix: pkgs.lib.hasPrefix (toString prefix) path) buildFiles;
-                  };
+      packages.x86_64-linux = {
+        inherit ghc;
+        inherit stack;
+        inherit utoy;
 
-              libraryHaskellDepends = haskellDeps haskellPackages;
-            };
-        in
-          pkgs.haskell.lib.justStaticExecutables (haskellPackages.callPackage utoy {});
+        default = utoy;
+      };
 
-      packages.x86_64-linux.default = self.packages.x86_64-linux.utoy;
-
-      devShells.default = pkgs.mkShell {
-        buildInputs = [
+      devShells.x86_64-linux.default = pkgs.mkShell {
+        packages = [
           stack
+          ghc
+
+          haskellPackages.haskell-language-server
+          haskellPackages.implicit-hie
         ];
         shellHook = ''
-          PS1+=" (utoy)";
+          PS1+="(utoy) ";
         '';
       };
   };

shell.nix

@@ -1,17 +0,0 @@
-{ pkgs ? import ./nix/pkgs.nix {} }:
-let
-  haskellDeps = import ./nix/haskell-deps.nix;
-  settings = import ./nix/settings.nix;
-  haskellPackages = pkgs.haskell.packages."${settings.ghc}";
-
-  tools = with pkgs; [
-    # haskell tools
-    stack
-    (haskellPackages.ghcWithPackages haskellDeps)
-    haskellPackages.haskell-language-server
-    haskellPackages.implicit-hie
-  ];
-in
-  pkgs.mkShellNoCC {
-    nativeBuildInputs = tools;
-  }

stack-shell.nix

@@ -1,10 +0,0 @@
-{}:
-let
-  pkgs = import ./nix/pkgs.nix {};
-  haskellDeps = import ./nix/haskell-deps.nix;
-  settings = import ./nix/settings.nix;
-in
-  pkgs.haskell.lib.buildStackProject {
-    name = "utoy";
-    ghc = pkgs.haskell.packages."${settings.ghc}".ghcWithPackages haskellDeps;
-  }

stack.yaml

@@ -1,9 +1,4 @@
+# You can get a working environment using nix develop.
 resolver: ghc-9.4.4
-# GHC is managed through Nix
-install-ghc: false
 packages:
 - .
-nix:
-  enable: true
-  shell-file: stack-shell.nix
-  path: ["nixpkgs=./nix/pkgs.nix"]