add input remapping module with easier configuration

hosts/catbook-j/configuration.nix

@@ -26,7 +26,22 @@
       social.enable = true;
       mail.enable = true;
       gaming.enable = true;
-      evremap.enable = true;
+    };
+    input.remapping = {
+      enable = true;
+      devices."AT Translated Set 2 keyboard" = {
+        swapKeys = [
+          ["KEY_Y" "KEY_Z"]
+          ["KEY_LEFTALT" "KEY_LEFTMETA"]
+        ];
+        dual_role = [
+          {
+            input = "KEY_CAPSLOCK";
+            hold = ["KEY_LEFTCTRL"];
+            tap = ["KEY_ESC"];
+          }
+        ];
+      };
     };
     terminal.enable = true;
   };

modules/desktop/default.nix

@@ -30,10 +30,11 @@ in
       ./social.nix
       ./mail.nix
       ./specific-hardware
-      ./evremap.nix
       ./xmonad.nix
       ./fonts.nix
       ./firefox.nix
+      ./x.nix
+      ./input
     ];
 
     i18n.inputMethod = {
@@ -52,32 +53,6 @@ in
     services = {
       printing.enable = true;
       gnome.gnome-keyring.enable = true;
-
-      xserver = {
-        enable = true;
-
-        xkb = {
-          layout = "us";
-          variant = "altgr-intl";
-        };
-
-        libinput = {
-          enable = true;
-        };
-
-        desktopManager = {
-          xterm.enable = false;
-        };
-
-        displayManager = {
-          defaultSession = "none+xmonad";
-          gdm.enable = true;
-        };
-
-        windowManager.xmonad = {
-          enable = true;
-        };
-      };
     };
 
     programs.xss-lock = {

modules/desktop/evremap.nix

@@ -1,39 +0,0 @@
-{
-  pkgs,
-  config,
-  lib,
-  ...
-}: let
-  cfg = config.jade.desktop.evremap;
-  evremap = pkgs.rustPlatform.buildRustPackage {
-    pname = "evremap";
-    version = "0.1.0";
-    src = pkgs.fetchFromGitHub {
-      owner = "wez";
-      repo = "evremap";
-      rev = "4480c4eda223b98899b0fbd926bc34f7bd0e1a18";
-      sha256 = "sha256-BxSrphgW1n465FX6bKVkq6O0XE2JqanfSYlsGwWUWkQ=";
-    };
-    cargoHash = "";
-    cargoLock.lockFile = ../../other/evremap.Cargo.lock;
-    postPatch = ''
-      cp ${../../other/evremap.Cargo.lock} Cargo.lock
-    '';
-    nativeBuildInputs = [pkgs.pkg-config];
-    buildInputs = [pkgs.libevdev];
-  };
-in
-  with lib; {
-    options.jade.desktop.evremap = {
-      enable = mkEnableOption "Enable evremap";
-    };
-    config = mkIf cfg.enable {
-      systemd.services.evremap = {
-        script = "${evremap}/bin/evremap remap ${../../other/remaps-${config.networking.hostName}.toml}";
-        wantedBy = ["multi-user.target"];
-        unitConfig = {
-          Restart = "on-failure";
-        };
-      };
-    };
-  }

modules/desktop/input/default.nix

@@ -0,0 +1,15 @@
+{...}: {
+  imports = [
+    ./evremap.nix
+  ];
+  services.xserver = {
+    xkb = {
+      layout = "us";
+      variant = "altgr-intl";
+    };
+
+    libinput = {
+      enable = true;
+    };
+  };
+}

modules/desktop/input/evremap.nix

@@ -0,0 +1,110 @@
+{
+  pkgs,
+  config,
+  lib,
+  utils,
+  ...
+}: let
+  cfg = config.jade.input.remapping;
+  evremap = pkgs.rustPlatform.buildRustPackage {
+    pname = "evremap";
+    version = "0.1.0";
+    src = pkgs.fetchFromGitHub {
+      owner = "wez";
+      repo = "evremap";
+      rev = "4480c4eda223b98899b0fbd926bc34f7bd0e1a18";
+      sha256 = "sha256-BxSrphgW1n465FX6bKVkq6O0XE2JqanfSYlsGwWUWkQ=";
+    };
+    cargoHash = "";
+    cargoLock.lockFile = ../../../other/evremap.Cargo.lock;
+    postPatch = ''
+      cp ${../../../other/evremap.Cargo.lock} Cargo.lock
+    '';
+    nativeBuildInputs = [pkgs.pkg-config];
+    buildInputs = [pkgs.libevdev];
+  };
+  toml = pkgs.formats.toml {};
+in
+  with lib; {
+    options.jade.input.remapping = {
+      enable = mkEnableOption "Enable evremap";
+      devices = mkOption {
+        type = types.attrsOf (types.submodule ({name, ...}: {
+          options = {
+            device_name = mkOption {
+              type = types.str;
+              description = "The device name";
+              default = name;
+            };
+            remap = mkOption {
+              type = types.listOf (types.submodule ({...}: {
+                options.input = mkOption {type = types.listOf types.str;};
+                options.output = mkOption {type = types.listOf types.str;};
+              }));
+              default = [];
+            };
+            swapKeys = mkOption {
+              description = "Lists with two keys to be swapped on the keyboard layout.";
+              type = types.listOf (
+                # verify that each key swapping list contains two elements
+                types.addCheck (types.listOf types.str) (v: builtins.length v == 2)
+              );
+              default = [];
+            };
+            dual_role = mkOption {
+              type = types.listOf (types.submodule ({...}: {
+                options.input = mkOption {type = types.str;};
+                options.hold = mkOption {type = types.listOf types.str;};
+                options.tap = mkOption {type = types.listOf types.str;};
+              }));
+              default = [];
+            };
+          };
+        }));
+      };
+    };
+    config = mkIf cfg.enable (
+      with builtins; let
+        devs = map ({
+          device_name,
+          remap,
+          swapKeys,
+          dual_role,
+        }: {
+          inherit device_name dual_role;
+
+          # expand swapKeys to normal remaps
+          remap = concatLists [
+            remap
+            (lib.lists.flatten (map (keys: [
+                {
+                  input = [(head keys)];
+                  output = [(lib.lists.last keys)];
+                }
+                {
+                  input = [(lib.lists.last keys)];
+                  output = [(head keys)];
+                }
+              ])
+              swapKeys))
+          ];
+        }) (attrValues cfg.devices);
+      in {
+        # generate numbered systemd services for each device to be remapped
+        # https://github.com/wez/evremap/issues/17
+        systemd.services = listToAttrs (genList (i: {
+          name = "evremap${toString i}";
+          value = let
+            cfgFile = toml.generate "remaps-${toString i}.toml" (elemAt devs i);
+          in {
+            script = "${evremap}/bin/evremap remap ${cfgFile}";
+            wantedBy = ["multi-user.target"];
+            unitConfig = {
+              Restart = "on-failure";
+            };
+          };
+        }) (length devs));
+        environment.systemPackages = [evremap];
+      }
+    );
+  }

modules/desktop/x.nix

@@ -0,0 +1,18 @@
+{...}: {
+  services.xserver = {
+    enable = true;
+
+    desktopManager = {
+      xterm.enable = false;
+    };
+
+    displayManager = {
+      defaultSession = "none+xmonad";
+      gdm.enable = true;
+    };
+
+    windowManager.xmonad = {
+      enable = true;
+    };
+  };
+}

other/remaps-catbook-j.toml

@@ -1,22 +0,0 @@
-device_name = "AT Translated Set 2 keyboard"
- 
-[[remap]]
-input = [ "KEY_Y" ]
-output = [ "KEY_Z" ]
-
-[[remap]]
-input = [ "KEY_Z" ]
-output = [ "KEY_Y" ]
-
-[[remap]]
-input = [ "KEY_LEFTALT" ]
-output = [ "KEY_LEFTMETA" ]
-
-[[remap]]
-input = [ "KEY_LEFTMETA" ]
-output = [ "KEY_LEFTALT" ]
-
-[[dual_role]]
-input = "KEY_CAPSLOCK"
-hold = ["KEY_LEFTCTRL"]
-tap = ["KEY_ESC"]