Install qbar with nix

nixos/layers/desktop.nix

@@ -57,6 +57,7 @@ in
     adwaita-qt
 
     # qbar block dependencies
+    qbar
     python3
     acpi
     perl

nixos/pkgs/default.nix

@@ -14,6 +14,23 @@ let
     simpleandsoft = (import ./simpleandsoft { inherit pkgs; }).simpleandsoft;
     neatvnc = callPackage ./neatvnc/neatvnc.nix {};
     wayvnc = callPackage ./wayvnc/wayvnc.nix {};
+
+    haskell = pkgs.haskell // {
+      packageOverrides = self: super: {
+        qbar = self.callPackage ./qbar {};
+      };
+    };
+    mumble-git = (mumble.overrideAttrs (attrs: {
+      src = pkgs.fetchFromGitHub {
+        owner = "mumble-voip";
+        repo = "mumble";
+        rev = "f8ee53688353c8f5e1650504a961ee582ac16668";
+        sha256 = "1ifax91w5d0311sx8nkflfih61ccn0vcghyl1j6r8qn96zvz5dzq";
+        fetchSubmodules = true;
+      };
+    }));
+
+    qbar = haskellPackages.qbar;
   };
 
 in newpkgs

nixos/pkgs/qbar/default.nix

+{ haskell, fetchgit, callCabal2nix }:
+
+let
+  repo = with builtins; fromJSON ( readFile ./repo.json );
+  src = fetchgit {
+    inherit (repo) url rev sha256;
+  };
+in
+haskell.lib.generateOptparseApplicativeCompletion "qbar" (
+  callCabal2nix "qbar" src {}
+)

nixos/pkgs/qbar/repo.json

+{
+  "ref": "refs/heads/master",
+  "url": "https://git.c3pb.de/jens/qbar.git",
+  "rev": "5c8ef1e1adfae4414f11392b63662d2791f45634",
+  "date": "2020-03-19T22:27:09+01:00",
+  "sha256": "0q7ikpscxjrbbxzl5vqbf6szzfc05l4gh4f1x2zdwswny5a5qd93",
+  "fetchSubmodules": false,
+  "deepClone": false,
+  "leaveDotGit": false
+}

nixos/pkgs/qbar/update

+#!/usr/bin/env nix-shell
+#! nix-shell -i sh -p nix-prefetch-git jq
+
+url="https://git.c3pb.de/jens/qbar.git"
+ref="refs/heads/master"
+
+nix-prefetch-git --rev "$ref" --no-deepClone "$url" | jq --arg ref "$ref" '{ref: $ref} + .' > repo.json