feat(keyboard): per-device layout for external keyboards

Add nomarchy.keyboard.devices ({ "<hyprctl-device-name>" = { layout; variant; }; })
generating Hyprland `device` blocks that override the session
nomarchy.keyboard.layout for a named keyboard -- e.g. an external board
that's physically a different layout than the laptop's built-in one.
Hyprland applies it whenever that device connects, so the external keyboard
"remembers" its layout the declarative way. A Waybar hyprland/language
indicator shows the active layout, placed only when more than one layout is
in play (a comma in the session layout, or any per-device override) so
single-layout bars stay clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -188,6 +188,7 @@ examples: **[docs/OVERRIDES.md](docs/OVERRIDES.md)**.
 | `nomarchy.terminal` | `"ghostty"` | Terminal for keybinds and `$TERMINAL` |
 | `nomarchy.keyboard.layout` | `"us"` | XKB layout for the Hyprland session (installer writes the matching `services.xserver.xkb` in system.nix; the console + LUKS prompt follow via the distro default) |
 | `nomarchy.keyboard.variant` | `""` | XKB variant for the session |
+| `nomarchy.keyboard.devices` | `{}` | Per-device layout overrides (Hyprland `device` blocks keyed by `hyprctl devices` name) — e.g. an external keyboard with its own layout/variant |
 | `nomarchy.hyprland.enable` | `true` | Nomarchy's Hyprland config |
 | `nomarchy.waybar.enable` | `true` | Nomarchy's Waybar |
 | `nomarchy.rofi.enable` | `true` | Themed rofi launcher + `nomarchy-menu` dispatcher |

docs/ROADMAP.md

@@ -283,11 +283,21 @@ how to override it. Items marked ✓ are shipped.
 - **Night light / blue-light filter:** schedulable colour-temperature shift
   via `hyprsunset` (Hyprland-native; wlsunset/gammastep are alternatives) —
   sunset/sunrise or a fixed schedule, with a menu + Waybar toggle.
-- **Runtime keyboard-layout switching:** the session layout is a single
-  `nomarchy.keyboard.layout` today. Support a list of layouts with a toggle
-  bind (`hyprctl switchxkblayout` / xkb `grp:` options) and a Waybar
-  indicator for the active layout. Natural follow-on to the LUKS-keymap work
-  — keep the system (console/initrd) and session layouts in sync.
+- **Keyboard layouts (per-device + switching):**
+  - ✓ **Per-device declarative layout:** `nomarchy.keyboard.devices`
+    (`{ "<hyprctl-device-name>" = { layout; variant; }; }`) generates Hyprland
+    `device` blocks that override the session `nomarchy.keyboard.layout` for a
+    named keyboard — e.g. an external board that's physically a different
+    layout than the laptop's. Hyprland applies it whenever that device
+    connects (the "external keyboard remembers its layout" case, done the
+    declarative way). A Waybar `hyprland/language` indicator shows the active
+    layout, gated on more than one layout being in play (comma in the session
+    layout, or any per-device override) so single-layout bars stay clean.
+  - Remaining: a multi-layout cycle bind (`hyprctl switchxkblayout` / xkb
+    `grp:` options) for switching layouts on one keyboard; add the
+    `hyprland/language` module to the summer whole-swap themes for parity
+    (the gating doesn't translate to their static JSON). Keep the system
+    (console/initrd) and session layouts in sync (the LUKS-keymap work).
 - ✓ **Do-Not-Disturb:** swaync DND toggle wired into the menu
   (`nomarchy-menu dnd`, in the picker, SUPER+CTRL+D) and a Waybar bell
   indicator (`custom/notification` via `swaync-client -swb`: shows the

modules/home/hyprland.nix

@@ -150,6 +150,14 @@ in
         touchpad.natural_scroll = lib.mkDefault true;
       };
 
+      # Per-device keyboard layouts (nomarchy.keyboard.devices): each
+      # overrides the session kb_layout for one named keyboard — e.g. an
+      # external board that's physically a different layout than the laptop's
+      # built-in one. Hyprland applies them whenever the device connects.
+      device = lib.mapAttrsToList
+        (name: d: { inherit name; kb_layout = d.layout; kb_variant = d.variant; })
+        config.nomarchy.keyboard.devices;
+
       # dwindle:pseudotile was removed in Hyprland 0.55 (the `pseudo`
       # dispatcher still exists); setting it aborts config parsing.
       dwindle.preserve_split = lib.mkDefault true;

modules/home/options.nix

@@ -96,6 +96,33 @@ in
       description = "XKB variant for the Hyprland session.";
     };
 
+    keyboard.devices = lib.mkOption {
+      type = lib.types.attrsOf (lib.types.submodule {
+        options = {
+          layout = lib.mkOption {
+            type = lib.types.str;
+            description = "XKB layout for this specific keyboard.";
+          };
+          variant = lib.mkOption {
+            type = lib.types.str;
+            default = "";
+            description = "XKB variant for this keyboard.";
+          };
+        };
+      });
+      default = { };
+      example = lib.literalExpression ''{ "keychron-keychron-k2" = { layout = "de"; }; }'';
+      description = ''
+        Per-device keyboard layout. The key is the device name from
+        `hyprctl devices` (lower-case, hyphenated). Each entry generates a
+        Hyprland `device` block that overrides the session-wide
+        nomarchy.keyboard.layout for that keyboard only — e.g. an external
+        keyboard that's physically a different layout than the laptop's
+        built-in one. Hyprland applies it automatically whenever that
+        keyboard is connected.
+      '';
+    };
+
     package = lib.mkOption {
       type = lib.types.package;
       default = pkgs.nomarchy-theme-sync;

modules/home/waybar.nix

@@ -12,6 +12,12 @@
 let
   t = config.nomarchy.theme;
 
+  # Show the active-keyboard-layout indicator only when more than one layout
+  # is in play — multiple session layouts (comma-separated) or per-device
+  # overrides (nomarchy.keyboard.devices) — so single-layout bars stay clean.
+  showLanguage = lib.hasInfix "," config.nomarchy.keyboard.layout
+    || config.nomarchy.keyboard.devices != { };
+
   # Power-profile indicator (power-profiles-daemon). Both scripts self-
   # gate: they exit silently unless this is a laptop (a battery is
   # present) running PPD, so the module hides itself on desktops and
@@ -70,7 +76,9 @@ let
 
     modules-left = [ "hyprland/workspaces" "hyprland/window" ];
     modules-center = [ "clock" ];
-    modules-right = [ "tray" "pulseaudio" "network" "cpu" "memory" "custom/powerprofile" "battery" "custom/notification" ];
+    modules-right = [ "tray" "pulseaudio" "network" "cpu" "memory" "custom/powerprofile" ]
+      ++ lib.optional showLanguage "hyprland/language"
+      ++ [ "battery" "custom/notification" ];
 
     "hyprland/workspaces" = {
       format = "{icon}";
@@ -88,6 +96,13 @@ let
       tooltip-format = "<tt><small>{calendar}</small></tt>";
     };
 
+    # Active keyboard layout (per focused device) — only placed in
+    # modules-right when showLanguage (see above).
+    "hyprland/language" = {
+      format = "󰌌 {short}";
+      tooltip = false;
+    };
+
     pulseaudio = {
       format = "{icon} {volume}%";
       format-muted = "󰝟";
@@ -193,7 +208,7 @@ let
       font-weight: bold;
     }
 
-    #tray, #pulseaudio, #network, #cpu, #memory, #custom-powerprofile, #battery, #custom-notification {
+    #tray, #pulseaudio, #network, #cpu, #memory, #custom-powerprofile, #language, #battery, #custom-notification {
       color: @subtext;
       padding: 0 10px;
     }