treesitter: allow setting of filetype pattern and excludes for indent

docs/manual/release-notes/rl-0.9.md

@@ -390,4 +390,12 @@ https://github.com/gorbit99/codewindow.nvim
 
 - Add razor support for `roslyn_ls` and `csharp_ls`
 
+[mputz86](https://github.com/mputz86)
+
+- Add `vim.treesitter.indent.pattern` to specify file pattern(s) for which
+  treesitter indentation should be used
+- Add `vim.treesitter.indent.excludes` to exclude filetypes from the treesitter
+  indentation; e.g. useful for Haskell and PureScript, for which treesitter
+  indentation does not work good
+
 <!-- vim: set textwidth=80: -->

modules/plugins/treesitter/config.nix

@@ -4,8 +4,10 @@
   ...
 }: let
   inherit (lib.modules) mkIf;
+  inherit (lib.strings) optionalString;
   inherit (lib.lists) optionals;
   inherit (lib.nvim.dag) entryAfter;
+  inherit (lib.nvim.lua) toLuaObject;
 
   cfg = config.vim.treesitter;
 in {
@@ -39,8 +41,14 @@ in {
           -- Enable treesitter highlighting for all filetypes
           vim.api.nvim_create_autocmd("FileType", {
             group = "nvf_treesitter",
-            pattern = "*",
-            callback = function()
+            pattern = ${toLuaObject cfg.indent.pattern},
+            callback = function(args)
+          ${optionalString (builtins.length cfg.indent.excludes > 0) ''
+            local ft = vim.bo[args.buf].filetype
+            if vim.tbl_contains(${toLuaObject cfg.indent.excludes}, ft) then
+              return
+            end
+          ''}
               vim.bo.indentexpr = "v:lua.require'nvim-treesitter'.indentexpr()"
             end,
           })

modules/plugins/treesitter/treesitter.nix

@@ -4,7 +4,7 @@
   ...
 }: let
   inherit (lib.options) mkOption mkEnableOption literalExpression;
-  inherit (lib.types) listOf nullOr package bool;
+  inherit (lib.types) listOf nullOr package bool str oneOf;
 in {
   options.vim.treesitter = {
     enable = mkEnableOption "treesitter, also enabled automatically through language options";
@@ -64,7 +64,28 @@ in {
       '';
     };
 
-    indent = {enable = mkEnableOption "indentation with treesitter" // {default = true;};};
+    indent = {
+      enable = mkEnableOption "indentation with treesitter" // {default = true;};
+      pattern = mkOption {
+        type = oneOf [str (listOf str)];
+        default = "*";
+        example = literalExpression ''["lua" "nix"]'';
+        description = ''
+          Specify the filetype pattern(s) for which the treesitter indentation should be used.
+
+          See {command}`:h autocmd-pattern`.
+        '';
+      };
+      excludes = mkOption {
+        type = listOf str;
+        default = [];
+        example = literalExpression ''["haskell", "purescript"]'';
+        description = ''
+          Exclude the listed filetypes from using treesitter indentation.
+        '';
+      };
+    };
+
     highlight = {enable = mkEnableOption "highlighting with treesitter" // {default = true;};};
   };
 }