prepare basic structure

default.nix

@@ -1,39 +1,22 @@
-{ wrapNeovim, neovim-unwrapped, vimPlugins, ... }:
+{ callPackage, wrapNeovim, neovim-unwrapped, vimPlugins, ... }:
 
+let
+  lib = import ./lib.nix;
+
+  plugins = [
+    (callPackage ./syntax { })
+  ];
+
+in
 wrapNeovim neovim-unwrapped {
   withPython3 = false;
   withNodeJs = false;
   withRuby = false;
 
   configure = {
-    customRC = ''
-      lua << EOF
-        require("nvim-treesitter.configs").setup({
-          -- A list of parser names, or "all"
-          ensure_installed = {},
-
-          -- Install parsers synchronously (only applied to `ensure_installed`)
-          sync_install = false,
-
-          highlight = {
-            enable = true,
-          },
-
-          indent = {
-            enable = true,
-          },
-        })
-      EOF
-    '';
+    customRC = lib.mkLuaRc (lib.extractAttrs "luaConfig" plugins);
 
     packages.myVimPackages =
-      {
-        start = with vimPlugins; [
-          (nvim-treesitter.withPlugins
-            (ts: [
-              ts.tree-sitter-nix
-            ]))
-        ];
-      };
+      { start = lib.extractAttrs "plugins" plugins; };
   };
 }

lib.nix

@@ -0,0 +1,39 @@
+rec {
+  #############################################################################
+  # Helpers
+
+  # Source: https://github.com/NixOS/nixpkgs/blob/d61bc96d16ca288c69b798b8e31eca64050098e3/lib/lists.nix
+  foldr = op: nul: list:
+    let
+      len = builtins.length list;
+      fold' = n:
+        if n == len
+        then nul
+        else op (builtins.elemAt list n) (fold' (n + 1));
+    in
+    fold' 0;
+
+  extractAttrs = attr: list:
+    let
+      getAttr' = builtins.getAttr attr;
+      hasAttr' = builtins.hasAttr attr;
+      filteredList = builtins.filter hasAttr' list;
+    in
+    builtins.map getAttr' filteredList;
+
+  #############################################################################
+  # Lua
+
+  mkLuaHeredoc = content: ''
+    lua << EOF
+    ${content}
+    EOF
+  '';
+
+  mkLuaRc = contents:
+    let
+      concat = (a: b: a + b);
+      luaHeredors = builtins.map mkLuaHeredoc contents;
+    in
+    foldr concat "" luaHeredors;
+}

syntax/default.nix

@@ -0,0 +1,12 @@
+{ vimPlugins, ... }:
+
+{
+  luaConfig = builtins.readFile ./treesitter.lua;
+
+  plugins = [
+    (vimPlugins.nvim-treesitter.withPlugins
+      (ts: [
+        ts.tree-sitter-nix
+      ]))
+  ];
+}

syntax/treesitter.lua

@@ -0,0 +1,12 @@
+require("nvim-treesitter.configs").setup({
+  ensure_installed = {},
+  sync_install = false,
+
+  highlight = {
+    enable = true,
+  },
+
+  indent = {
+    enable = true,
+  },
+})