wrapper/lib: init with mkMappingOption

mkMappingOption wants to read a setting set in config without passing it
every time, so it should be defined in config.

modules/modules.nix

@@ -57,6 +57,7 @@
       "rc"
       "warnings"
       "lazy"
+      "lib"
     ];
 
     # Extra modules, such as deprecation warnings

modules/neovim/mappings/options.nix

@@ -1,5 +1,5 @@
 {lib, ...}: let
-  inherit (lib.options) mkOption literalMD;
+  inherit (lib.options) mkEnableOption mkOption literalMD;
   inherit (lib.types) either str listOf attrsOf nullOr submodule;
   inherit (lib.nvim.config) mkBool;
 
@@ -57,6 +57,8 @@
     };
 in {
   options.vim = {
+    vendoredKeymaps = mkEnableOption "this project's vendored keymaps by default" // {default = true;};
+
     keymaps = mkOption {
       type = listOf mapType;
       description = "Custom keybindings.";

modules/wrapper/lib/config.nix

@@ -0,0 +1,20 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit (lib.options) mkOption;
+  inherit (lib.types) nullOr str;
+in {
+  config.vim.lib = {
+    mkMappingOption = description: default:
+      mkOption {
+        type = nullOr str;
+        default =
+          if config.vim.vendoredKeymaps
+          then default
+          else null;
+        inherit description;
+      };
+  };
+}

modules/wrapper/lib/default.nix

@@ -0,0 +1,6 @@
+{
+  imports = [
+    ./config.nix
+    ./options.nix
+  ];
+}

modules/wrapper/lib/options.nix

@@ -0,0 +1,11 @@
+{lib, ...}: let
+  inherit (lib.options) mkOption;
+  inherit (lib.types) attrsOf raw;
+in {
+  options.vim.lib = mkOption {
+    # The second type should be one without merge semantics and which allows function values.
+    type = attrsOf raw;
+    default = {};
+    internal = true;
+  };
+}