neovim/queries: init and add an example injection

modules/plugins/treesitter/config.nix

@@ -1,9 +1,10 @@
 {
   config,
   lib,
+  pkgs,
   ...
 }: let
-  inherit (lib.modules) mkIf;
+  inherit (lib) mkIf foldl' mapAttrsToList;
   inherit (lib.strings) optionalString;
   inherit (lib.lists) optionals;
   inherit (lib.nvim.dag) entryAfter;
@@ -66,6 +67,40 @@ in {
           })
         ''}
       '';
+
+      additionalRuntimePaths = mkIf (cfg.queries != []) [
+        (let
+          grouped =
+            foldl'
+            (
+              acc: query:
+                foldl'
+                (
+                  inner: filetype: let
+                    path = "queries/${filetype}/${query.type}.scm";
+                    prev = inner.${path} or "";
+                  in
+                    inner
+                    // {
+                      ${path} = prev + query.content;
+                    }
+                )
+                acc
+                query.filetypes
+            )
+            {}
+            cfg.queries;
+
+          files =
+            mapAttrsToList
+            (path: content: {
+              name = path;
+              path = pkgs.writeText path content;
+            })
+            grouped;
+        in
+          pkgs.linkFarm "treesitter-queries" files)
+      ];
     };
   };
 }

modules/plugins/treesitter/treesitter.nix

@@ -4,7 +4,25 @@
   ...
 }: let
   inherit (lib.options) mkOption mkEnableOption literalExpression;
-  inherit (lib.types) listOf nullOr package bool str oneOf;
+  inherit (lib.types) listOf nullOr package bool str lines enum submodule oneOf;
+
+  queriesType = submodule {
+    options = {
+      type = mkOption {
+        type = enum ["injections" "highlights" "folds" "locals" "indents"];
+        description = "The kind of query to register.";
+      };
+      filetypes = mkOption {
+        type = listOf str;
+        default = [];
+        description = "The filetypes for which the query should be registered.";
+      };
+      content = mkOption {
+        type = lines;
+        description = "The queries scm script.";
+      };
+    };
+  };
 in {
   options.vim.treesitter = {
     enable = mkEnableOption "treesitter, also enabled automatically through language options";
@@ -87,5 +105,11 @@ in {
     };
 
     highlight = {enable = mkEnableOption "highlighting with treesitter" // {default = true;};};
+
+    queries = mkOption {
+      type = listOf queriesType;
+      default = [];
+      description = "A list of Neovim treesitter queries to be registered.";
+    };
   };
 }