1 files changed, 156 insertions, 0 deletions

diff --git a/modules/i18n.nix b/modules/i18n.nix
new file mode 100644
index 00000000..f84e8b64
--- /dev/null
+++ b/modules/i18n.nix
@@ -0,0 +1,156 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  aggregatedLocales =
+    (builtins.map
+      (l: (lib.replaceStrings [ "utf8" "utf-8" "UTF8" ] [ "UTF-8" "UTF-8" "UTF-8" ] l) + "/UTF-8")
+      (
+        [ config.i18n.defaultLocale ]
+        ++ (lib.optionals (builtins.isList config.i18n.extraLocales) config.i18n.extraLocales)
+        ++ (lib.attrValues (lib.filterAttrs (n: _v: lib.hasPrefix "LC_" n) config.i18n.extraLocaleSettings))
+      )
+    )
+    ++ (lib.optional (builtins.isString config.i18n.extraLocales) config.i18n.extraLocales);
+in
+{
+  disabledModules = [ "config/i18n.nix" ];
+
+  ###### interface
+
+  options = {
+
+    i18n = {
+      glibcLocales = lib.mkOption {
+        type = lib.types.path;
+        default = pkgs.glibcLocales.override {
+          allLocales = lib.any (x: x == "all") config.i18n.supportedLocales;
+          locales = config.i18n.supportedLocales;
+        };
+        defaultText = lib.literalExpression ''
+          pkgs.glibcLocales.override {
+            allLocales = lib.any (x: x == "all") config.i18n.supportedLocales;
+            locales = config.i18n.supportedLocales;
+          }
+        '';
+        example = lib.literalExpression "pkgs.glibcLocales";
+        description = ''
+          Customized pkg.glibcLocales package.
+
+          Changing this option can disable handling of i18n.defaultLocale
+          and supportedLocale.
+        '';
+      };
+
+      defaultLocale = lib.mkOption {
+        type = lib.types.str;
+        default = "en_US.UTF-8";
+        example = "nl_NL.UTF-8";
+        description = ''
+          The default locale.  It determines the language for program
+          messages, the format for dates and times, sort order, and so on.
+          It also determines the character set, such as UTF-8.
+        '';
+      };
+
+      extraLocales = lib.mkOption {
+        type = lib.types.either (lib.types.listOf lib.types.str) (lib.types.enum [ "all" ]);
+        default = [ ];
+        example = [ "nl_NL.UTF-8" ];
+        description = ''
+          Additional locales that the system should support, besides the ones
+          configured with {option}`i18n.defaultLocale` and
+          {option}`i18n.extraLocaleSettings`.
+          Set this to `"all"` to install all available locales.
+        '';
+      };
+
+      extraLocaleSettings = lib.mkOption {
+        type = lib.types.attrsOf lib.types.str;
+        default = { };
+        example = {
+          LC_MESSAGES = "en_US.UTF-8";
+          LC_TIME = "de_DE.UTF-8";
+        };
+        description = ''
+          A set of additional system-wide locale settings other than
+          `LANG` which can be configured with
+          {option}`i18n.defaultLocale`.
+        '';
+      };
+
+      supportedLocales = lib.mkOption {
+        type = lib.types.listOf lib.types.str;
+        visible = false;
+        default = lib.unique (
+          [
+            "C.UTF-8/UTF-8"
+            "en_US.UTF-8/UTF-8"
+          ]
+          ++ aggregatedLocales
+        );
+        example = [
+          "en_US.UTF-8/UTF-8"
+          "nl_NL.UTF-8/UTF-8"
+          "nl_NL/ISO-8859-1"
+        ];
+        description = ''
+          List of locales that the system should support.  The value
+          `"all"` means that all locales supported by
+          Glibc will be installed.  A full list of supported locales
+          can be found at <https://sourceware.org/git/?p=glibc.git;a=blob;f=localedata/SUPPORTED>.
+        '';
+      };
+
+    };
+
+  };
+
+  ###### implementation
+
+  config = {
+    warnings =
+      lib.optional
+        (
+          !(
+            (lib.subtractLists config.i18n.supportedLocales aggregatedLocales) == [ ]
+            || lib.any (x: x == "all") config.i18n.supportedLocales
+          )
+        )
+        ''
+          `i18n.supportedLocales` is deprecated in favor of `i18n.extraLocales`,
+          and it seems you are using `i18n.supportedLocales` and forgot to
+          include some locales specified in `i18n.defaultLocale`,
+          `i18n.extraLocales` or `i18n.extraLocaleSettings`.
+
+          If you're trying to install additional locales not specified in
+          `i18n.defaultLocale` or `i18n.extraLocaleSettings`, consider adding
+          only those locales to `i18n.extraLocales`.
+        '';
+
+    environment.systemPackages =
+      # We increase the priority a little, so that plain glibc in systemPackages can't win.
+      lib.optional (config.i18n.supportedLocales != [ ]) (lib.setPrio (-1) config.i18n.glibcLocales);
+
+    environment.sessionVariables = {
+      LANG = config.i18n.defaultLocale;
+      LOCALE_ARCHIVE = "/run/current-system/sw/lib/locale/locale-archive";
+    } // config.i18n.extraLocaleSettings;
+
+    systemd.globalEnvironment = lib.mkIf (config.i18n.supportedLocales != [ ]) {
+      LOCALE_ARCHIVE = "${config.i18n.glibcLocales}/lib/locale/locale-archive";
+    };
+
+    # ‘/etc/locale.conf’ is used by systemd.
+    environment.etc."locale.conf".source = pkgs.writeText "locale.conf" ''
+      LANG=${config.i18n.defaultLocale}
+      ${lib.concatStringsSep "\n" (
+        lib.mapAttrsToList (n: v: "${n}=${v}") config.i18n.extraLocaleSettings
+      )}
+    '';
+
+  };
+}