nixos: init programs.xonsh

nixos/modules/module-list.nix

@@ -84,6 +84,7 @@
   ./programs/venus.nix
   ./programs/wvdial.nix
   ./programs/xfs_quota.nix
+  ./programs/xonsh.nix
   ./programs/zsh/zsh.nix
   ./rename.nix
   ./security/acme.nix

nixos/modules/programs/xonsh.nix

@@ -0,0 +1,62 @@
+# This module defines global configuration for the xonsh.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfge = config.environment;
+
+  cfg = config.programs.xonsh;
+
+in
+
+{
+
+  options = {
+
+    programs.xonsh = {
+
+      enable = mkOption {
+        default = false;
+        description = ''
+          Whether to configure xnosh as an interactive shell.
+        '';
+        type = types.bool;
+      };
+
+      package = mkOption {
+        type = types.package;
+        example = literalExample "pkgs.xonsh.override { configFile = \"/path/to/xonshrc\"; }";
+        description = ''
+          xonsh package to use.
+        '';
+      };
+
+      config = mkOption {
+        default = "";
+        description = "Control file to customize your shell behavior.";
+        type = types.lines;
+      };
+
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    environment.etc."xonshrc".text = cfg.config;
+
+    environment.systemPackages = [ pkgs.xonsh ];
+
+    environment.shells =
+      [ "/run/current-system/sw/bin/xonsh"
+        "/var/run/current-system/sw/bin/xonsh"
+        "${pkgs.xonsh}/bin/xonsh"
+      ];
+
+  };
+
+}
+