modules: create modules to hold global variables

modules/default.nix

@@ -1,3 +1,7 @@
 {
-  imports = [./theme];
+  imports = [
+    ./systemVars.nix
+    ./homeVars.nix
+    ./theme
+  ];
 }

modules/homeVars.nix

@@ -0,0 +1,31 @@
+{
+  config,
+  lib,
+  options,
+  ...
+}: let
+  inherit (lib) mkIf mkOption;
+  inherit (lib.types) str;
+in {
+  options.local.homeVars = {
+    fullName = mkOption {
+      type = str;
+      description = "your full name (used for git commits and user description)";
+      default = null;
+    };
+    email = mkOption {
+      type = str;
+      description = "your email (used for git commits)";
+      default = null;
+    };
+  };
+
+  config.assertions = mkIf (!config.local.systemVars.isServer) [
+    {
+      assertion = options.local.homeVars.fullName.isDefined;
+    }
+    {
+      assertion = options.local.homeVars.email.isDefined;
+    }
+  ];
+}

modules/systemVars.nix

@@ -0,0 +1,35 @@
+{
+  lib,
+  options,
+  ...
+}: let
+  inherit (lib) mkOption;
+  inherit (lib.types) bool str;
+in {
+  options.local.systemVars = {
+    hostName = mkOption {
+      type = str;
+      description = "hostname for the current host";
+      default = null;
+    };
+    username = mkOption {
+      type = str;
+      description = "username for the home directory";
+      default = null;
+    };
+    isServer = mkOption {
+      type = bool;
+      description = "whether or not this host is a server";
+      default = false;
+    };
+  };
+
+  config.assertions = [
+    {
+      assertion = options.local.systemVars.hostName.isDefined;
+    }
+    {
+      assertion = options.local.systemVars.username.isDefined;
+    }
+  ];
+}