Per Language Indent Config

configuration.nix

@@ -49,7 +49,12 @@ isMaximal: {
       enableExtraDiagnostics = true;
 
       # Languages that will be supported in default and maximal configurations.
-      nix.enable = true;
+      nix = {
+        enable = true;
+        tabstop = 8;
+        softtabstop = 8;
+        shiftwidth = 8;
+      };
       markdown.enable = true;
 
       # Languages that are enabled in the maximal configuration.

flake.nix

@@ -27,6 +27,7 @@
       flake = {
         lib = {
           inherit (lib) nvim;
+          inherit (lib) generators;
           inherit (lib.nvim) neovimConfiguration;
         };
 

lib/languages.nix

@@ -4,6 +4,7 @@
   inherit (lib.types) listOf bool str submodule attrsOf anything either nullOr uniq;
   inherit (lib.nvim.attrsets) mapListToAttrs;
   inherit (lib.nvim.types) luaInline;
+  inherit (lib.generators) mkLuaInline;
 in {
   # TODO: remove
   diagnosticsToLua = {
@@ -77,4 +78,26 @@ in {
       };
     };
   };
+
+  # maybe put generic function to set indent for provided langs
+  # Then we can just call it with the lib arg
+
+  setLanguageIndent = {language, tabstop, softtabstop, shiftwidth}: {
+    vim.autocmds = [
+      {
+        desc = "Sets indent for nix files";
+        event = [ "FileType" ];
+        pattern = [ language ];
+        callback = mkLuaInline ''
+          function()
+            ${if tabstop != null then "vim.bo.tabstop = " + toString tabstop else ""}
+            ${if softtabstop != null then "vim.bo.softtabstop = " + toString softtabstop else ""}
+            ${if shiftwidth != null then "vim.bo.shiftwidth = " + toString shiftwidth else ""}
+          end
+        '';
+        once = true;
+      }
+    ];
+  };
+
 }

modules/plugins/languages/markdown.nix

@@ -13,6 +13,7 @@
   inherit (lib.nvim.types) diagnostics mkGrammarOption mkPluginSetupOption deprecatedSingleOrListOf;
   inherit (lib.nvim.dag) entryAnywhere;
   inherit (lib.nvim.attrsets) mapListToAttrs;
+  inherit (lib.nvim.languages) setLanguageIndent;
   inherit (lib.trivial) warn;
 
   cfg = config.vim.languages.markdown;
@@ -205,5 +206,8 @@ in {
           cfg.extraDiagnostics.types);
       };
     })
+
+    # todo
+
   ]);
 }

modules/plugins/languages/nix.nix

@@ -4,14 +4,15 @@
   lib,
   ...
 }: let
-  inherit (builtins) attrNames;
+  inherit (builtins) attrNames toString;
   inherit (lib) concatStringsSep;
   inherit (lib.meta) getExe;
   inherit (lib.options) mkEnableOption mkOption;
   inherit (lib.modules) mkIf mkMerge;
-  inherit (lib.types) enum;
+  inherit (lib.types) enum int nullOr;
   inherit (lib.nvim.types) mkGrammarOption diagnostics deprecatedSingleOrListOf;
   inherit (lib.nvim.attrsets) mapListToAttrs;
+  inherit (lib.nvim.languages) setLanguageIndent;
 
   cfg = config.vim.languages.nix;
 
@@ -106,6 +107,24 @@ in {
         inherit defaultDiagnosticsProvider;
       };
     };
+
+    tabstop = mkOption {
+      description = "Sets the tabstop size in spaces for .nix files";
+      type = nullOr int;
+      default = null;
+    };
+
+    softtabstop = mkOption {
+      description = "Sets the softtabstop size in spaces for .nix files";
+      type = nullOr int;
+      default = null;
+    };
+
+    shiftwidth = mkOption {
+      description = "Sets the shiftwidth in spaces for .nix files";
+      type = nullOr int;
+      default = null;
+    };
   };
 
   config = mkIf cfg.enable (mkMerge [
@@ -160,5 +179,13 @@ in {
           cfg.extraDiagnostics.types);
       };
     })
+
+    (setLanguageIndent {
+      language = "nix";
+      tabstop = cfg.tabstop;
+      softtabstop = cfg.softtabstop;
+      shiftwidth = cfg.shiftwidth;
+    })
+
   ]);
 }