modules: add documentation

modules/default.nix

@@ -3,6 +3,7 @@
 
 {
   imports = [
+    ./documentation.nix
     ./ergodox.nix
     ./language.nix
     ./media.nix

modules/documentation.nix

@@ -0,0 +1,37 @@
+{ config, lib, ... }:
+let
+  cfg = config.my.module.documentation;
+
+  # I usually want everything enabled at once, but keep it customizable
+  defaultToGlobal = description: lib.mkEnableOption description // {
+    default = cfg.enable;
+  };
+in
+{
+  options.my.module.documentation = with lib.my; {
+    enable = mkDisableOption "Documentation integration";
+
+    dev.enable = defaultToGlobal "Documentation aimed at developers";
+
+    info.enable = defaultToGlobal "Documentation aimed at developers";
+
+    man.enable = defaultToGlobal "Documentation aimed at developers";
+
+    nixos.enable = defaultToGlobal "NixOS documentation";
+  };
+
+  config.documentation = {
+    enable = cfg.enable;
+
+    dev.enable = cfg.dev.enable;
+
+    info.enable = cfg.info.enable;
+
+    man = {
+      enable = cfg.man.enable;
+      generateCaches = true;
+    };
+
+    nixos.enable = cfg.nixos.enable;
+  };
+}