From 6e6ce2c1fcaaa57cd25fa2a59c5fb77b0474705f Mon Sep 17 00:00:00 2001
From: maralorn <mail@maralorn.de>
Date: Fri, 3 Mar 2023 00:06:45 +0100
Subject: [PATCH] Much better Haskell environment

---
 overlays/flake-module.nix |  1 -
 overlays/ghc/default.nix  | 24 +++++++++++++++++++-----
 packages/flake-module.nix |  6 +++---
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/overlays/flake-module.nix b/overlays/flake-module.nix
index a4045bb0..d1fa9e8d 100644
--- a/overlays/flake-module.nix
+++ b/overlays/flake-module.nix
@@ -14,7 +14,6 @@
           flake-inputs = inputs;
           flake-inputs' = inputs';
         })
-        inputs.self.overlays.addMyHaskellPackages
       ]
       ++ (let
         overlayPath = ./.;
diff --git a/overlays/ghc/default.nix b/overlays/ghc/default.nix
index 00a6f96d..ffe42eda 100644
--- a/overlays/ghc/default.nix
+++ b/overlays/ghc/default.nix
@@ -1,6 +1,20 @@
-final: _: let
+final: prev: let
   myPkgs = import ./packages.nix;
-in {
-  myHaskellScriptPackages = myPkgs.makeHaskellScriptPackages final.haskellPackages;
-  ghcWithPackages = final.unstableGhc.withHoogle (p: builtins.attrValues (myPkgs.makeHaskellPackages p // (final.flake-inputs.self.overlays.addMyHaskellPackages "" "")));
-}
+  inherit (prev.flake-inputs) self;
+  inherit (self.lib) selectHaskellPackages;
+  hpkgs = final.unstableHaskellPackages.override {
+    overrides = self.overlays.haskellPackagesOverlay;
+  };
+  shell = hpkgs.shellFor {
+    withHoogle = true;
+    packages = p: builtins.attrValues (self.lib.selectHaskellPackages p);
+    extraDependencies = p: {
+      libraryHaskellDepends = builtins.attrValues (myPkgs.makeHaskellPackages p // selectHaskellPackages p);
+    };
+  };
+in
+  {
+    myHaskellScriptPackages = myPkgs.makeHaskellScriptPackages final.haskellPackages;
+    ghcWithPackages = builtins.head shell.nativeBuildInputs;
+  }
+  // selectHaskellPackages hpkgs
diff --git a/packages/flake-module.nix b/packages/flake-module.nix
index 188e1036..a20cb21e 100644
--- a/packages/flake-module.nix
+++ b/packages/flake-module.nix
@@ -80,9 +80,9 @@
   };
   packages = selectHaskellPackages hpkgs;
 in {
-  flake.overlays = {
-    inherit haskellPackagesOverlay;
-    addMyHaskellPackages = _: _: packages;
+  flake = {
+    lib = {inherit selectHaskellPackages;};
+    overlays = {inherit haskellPackagesOverlay;};
   };
   perSystem = {config, ...}: {
     inherit packages;