Initial commit

flake/den/modules/aspects/provides/user-shell.nix

@@ -0,0 +1,41 @@
+{ den, ... }:
+let
+
+  description = ''
+    Sets a user default shell, enables the shell at OS and Home level.
+
+    Usage:
+
+      den.aspects.vic.includes = [
+        # will always love red snappers.
+        (den._.user-shell "fish")
+      ];
+  '';
+
+  userShell =
+    shell: user:
+    let
+      nixos =
+        { pkgs, ... }:
+        {
+          programs.${shell}.enable = true;
+          users.users.${user.userName}.shell = pkgs.${shell};
+        };
+      darwin = nixos;
+      homeManager.programs.${shell}.enable = true;
+    in
+    {
+      inherit nixos darwin homeManager;
+    };
+
+in
+{
+  den.provides.user-shell = shell: {
+    inherit description;
+    __functor = den.lib.parametric.atLeast;
+    includes = [
+      ({ user, ... }: userShell shell user)
+      ({ home, ... }: userShell shell home)
+    ];
+  };
+}