shell: chunk up usecases

shell.nix

@@ -7,29 +7,26 @@
         ./nix/packages/overlay.nix
       ];
     },
-}:
-pkgs.mkShell {
-  name = "dotfiles";
-  packages = with pkgs; [
-    #
-    # Just scripts
-    #
-    just
-    jq
+}: rec {
+  default = pkgs.mkShell {
+    packages = with pkgs; [
+      just
+      jq
+      npins
+      disko
+    ];
+  };
 
-    #
-    # XMonad
-    #
-    (haskellPackages.ghcWithPackages (self: [
-      self.xmonad-contrib
-      self.xmonad-extras
-    ]))
-    haskell-language-server
-    cabal-install
+  withXMonad = pkgs.mkShell {
+    inputsFrom = with pkgs; [
+      default
 
-    #
-    # Installer testing
-    #
-    disko
-  ];
+      (haskellPackages.ghcWithPackages (self: [
+        self.xmonad-contrib
+        self.xmonad-extras
+      ]))
+      haskell-language-server
+      cabal-install
+    ];
+  };
 }