modules/output: produce empty files by default

lib/neovim-plugin.nix

@@ -110,11 +110,12 @@ with lib;
           {
             extraPlugins = (optional installPackage cfg.package) ++ extraPlugins;
             inherit extraPackages;
-
-            ${extraConfigNamespace} = optionalString callSetup ''
+          }
+          (optionalAttrs callSetup {
+            ${extraConfigNamespace} = ''
               require('${luaName}')${setup}(${optionalString (cfg ? settings) (toLuaObject cfg.settings)})
             '';
-          }
+          })
           (optionalAttrs (isColorscheme && (colorscheme != null)) { colorscheme = mkDefault colorscheme; })
           (extraConfig cfg)
         ]);

lib/utils.nix

@@ -4,7 +4,14 @@
   _nixvimTests,
 }:
 with lib;
-{
+rec {
+  # Whether a string contains something other than whitespaces
+  hasContent = str: builtins.match "[[:space:]]*" str == null;
+
+  # Concatenate a list of strings, adding a newline at the end of each one,
+  # but skipping strings containing only whitespace characters
+  concatNonEmptyLines = lines: concatLines (builtins.filter hasContent lines);
+
   listToUnkeyedAttrs =
     list:
     builtins.listToAttrs (lib.lists.imap0 (idx: lib.nameValuePair "__unkeyed-${toString idx}") list);
@@ -118,4 +125,26 @@ with lib;
       ${string}
     end
   '';
+
+  # Wrap Vimscript for using in lua,
+  # but only if the string contains something other than whitespaces
+  # TODO: account for a possible ']]' in the string
+  wrapVimscriptForLua =
+    string:
+    optionalString (hasContent string) ''
+      vim.cmd([[
+      ${string}
+      ]])
+    '';
+
+  # Wrap lua script for using in Vimscript,
+  # but only if the string contains something other than whitespaces
+  # TODO: account for a possible 'EOF' if the string
+  wrapLuaForVimscript =
+    string:
+    optionalString (hasContent string) ''
+      lua << EOF
+      ${string}
+      EOF
+    '';
 }

modules/autocmd.nix

@@ -42,7 +42,7 @@ with lib;
     let
       inherit (config) autoGroups autoCmd;
     in
-    mkIf (autoGroups != { } || autoCmd != { }) {
+    mkIf (autoGroups != { } || autoCmd != [ ]) {
       # Introduced early October 2023.
       # TODO remove in early December 2023.
       assertions = [

modules/diagnostics.nix

@@ -19,7 +19,7 @@ with lib;
   };
 
   config = {
-    extraConfigLuaPre = optionalString (config.diagnostics != { }) ''
+    extraConfigLuaPre = mkIf (config.diagnostics != { }) ''
       vim.diagnostic.config(${helpers.toLuaObject config.diagnostics})
     '';
   };

modules/highlights.nix

@@ -35,50 +35,52 @@ with lib;
     };
   };
 
-  config = {
-    extraConfigLuaPre =
-      (optionalString (config.highlight != { })
-        # lua
-        ''
-          -- Highlight groups {{
-          do
-            local highlights = ${helpers.toLuaObject config.highlight}
+  config = mkMerge [
+    {
+      extraConfigLuaPre =
+        mkIf (config.highlight != { })
+          # lua
+          ''
+            -- Highlight groups {{
+            do
+              local highlights = ${helpers.toLuaObject config.highlight}
 
-            for k,v in pairs(highlights) do
-              vim.api.nvim_set_hl(0, k, v)
+              for k,v in pairs(highlights) do
+                vim.api.nvim_set_hl(0, k, v)
+              end
             end
-          end
-          -- }}
-        ''
-      )
-      + (optionalString (config.match != { })
-        # lua
-        ''
-          -- Match groups {{
-          do
-            local match = ${helpers.toLuaObject config.match}
+            -- }}
+          '';
+      extraConfigLuaPost =
+        mkIf (config.highlightOverride != { })
+          # lua
+          ''
+            -- Highlight groups {{
+            do
+              local highlights = ${helpers.toLuaObject config.highlightOverride}
 
-            for k,v in pairs(match) do
-              vim.fn.matchadd(k, v)
+              for k,v in pairs(highlights) do
+                vim.api.nvim_set_hl(0, k, v)
+              end
             end
-          end
             -- }}
-        ''
-      );
-
-    extraConfigLuaPost =
-      optionalString (config.highlightOverride != { })
-        # lua
-        ''
-          -- Highlight groups {{
-          do
-            local highlights = ${helpers.toLuaObject config.highlightOverride}
+          '';
+    }
+    {
+      extraConfigLuaPre =
+        mkIf (config.match != { })
+          # lua
+          ''
+            -- Match groups {{
+            do
+              local match = ${helpers.toLuaObject config.match}
 
-            for k,v in pairs(highlights) do
-              vim.api.nvim_set_hl(0, k, v)
+              for k,v in pairs(match) do
+                vim.fn.matchadd(k, v)
+              end
             end
-          end
-          -- }}
-        '';
-  };
+              -- }}
+          '';
+    }
+  ];
 }

modules/keymaps.nix

@@ -90,7 +90,7 @@ with lib;
           ${concatStringsSep "\n" luaDefs}
         '';
 
-      extraConfigLua = optionalString (config.keymaps != [ ]) ''
+      extraConfigLua = mkIf (config.keymaps != [ ]) ''
         -- Set up keybinds {{{
         do
           local __nixvim_binds = ${helpers.toLuaObject (map normalizeMapping config.keymaps)}

modules/opts.nix

@@ -55,31 +55,35 @@ in
   };
 
   config = {
-    extraConfigLuaPre = concatLines (
-      mapAttrsToList (
-        optionName:
-        {
-          prettyName,
-          luaVariableName,
-          luaApi,
-          ...
-        }:
-        let
-          varName = "nixvim_${luaVariableName}";
-          optionDefinitions = config.${optionName};
-        in
-        optionalString (optionDefinitions != { }) ''
-          -- Set up ${prettyName} {{{
-          do
-            local ${varName} = ${helpers.toLuaObject optionDefinitions}
+    extraConfigLuaPre =
+      let
+        content = helpers.concatNonEmptyLines (
+          mapAttrsToList (
+            optionName:
+            {
+              prettyName,
+              luaVariableName,
+              luaApi,
+              ...
+            }:
+            let
+              varName = "nixvim_${luaVariableName}";
+              optionDefinitions = config.${optionName};
+            in
+            optionalString (optionDefinitions != { }) ''
+              -- Set up ${prettyName} {{{
+              do
+                local ${varName} = ${helpers.toLuaObject optionDefinitions}
 
-            for k,v in pairs(${varName}) do
-              vim.${luaApi}[k] = v
-            end
-          end
-          -- }}}
-        ''
-      ) optionsAttrs
-    );
+                for k,v in pairs(${varName}) do
+                  vim.${luaApi}[k] = v
+                end
+              end
+              -- }}}
+            ''
+          ) optionsAttrs
+        );
+      in
+      mkIf (content != "") content;
   };
 }

modules/output.nix

@@ -1,4 +1,9 @@
-{ lib, config, ... }:
+{
+  lib,
+  config,
+  helpers,
+  ...
+}:
 with lib;
 let
   pluginWithConfigType = types.submodule {
@@ -97,29 +102,27 @@ in
     };
   };
 
-  config =
-    let
-      contentLua = ''
-        ${config.extraConfigLuaPre}
-        vim.cmd([[
-          ${config.extraConfigVim}
-        ]])
-        ${config.extraConfigLua}
-        ${config.extraConfigLuaPost}
-      '';
-
-      contentVim = ''
-        lua << EOF
-          ${config.extraConfigLuaPre}
-        EOF
-        ${config.extraConfigVim}
-        lua << EOF
-          ${config.extraConfigLua}
-          ${config.extraConfigLuaPost}
-        EOF
-      '';
-    in
-    {
-      content = if config.type == "lua" then contentLua else contentVim;
-    };
+  config = {
+    content =
+      if config.type == "lua" then
+        # Lua
+        helpers.concatNonEmptyLines [
+          config.extraConfigLuaPre
+          (helpers.wrapVimscriptForLua config.extraConfigVim)
+          config.extraConfigLua
+          config.extraConfigLuaPost
+        ]
+      else
+        # Vimscript
+        helpers.concatNonEmptyLines [
+          (helpers.wrapLuaForVimscript config.extraConfigLuaPre)
+          config.extraConfigVim
+          (helpers.wrapLuaForVimscript (
+            helpers.concatNonEmptyLines [
+              config.extraConfigLua
+              config.extraConfigLuaPost
+            ]
+          ))
+        ];
+  };
 }

modules/top-level/output.nix

@@ -107,16 +107,10 @@ with lib;
         }
       );
 
-      customRC =
-        let
-          hasContent = str: (builtins.match "[[:space:]]*" str) == null;
-        in
-        (optionalString (hasContent neovimConfig.neovimRcContent) ''
-          vim.cmd([[
-            ${neovimConfig.neovimRcContent}
-          ]])
-        '')
-        + config.content;
+      customRC = helpers.concatNonEmptyLines [
+        (helpers.wrapVimscriptForLua neovimConfig.neovimRcContent)
+        config.content
+      ];
 
       init = helpers.writeLua "init.lua" customRC;
 
@@ -146,7 +140,7 @@ with lib;
         '';
       };
 
-      extraConfigLuaPre = lib.optionalString config.wrapRc ''
+      extraConfigLuaPre = lib.mkIf config.wrapRc ''
         -- Ignore the user lua configuration
         vim.opt.runtimepath:remove(vim.fn.stdpath('config'))              -- ~/.config/nvim
         vim.opt.runtimepath:remove(vim.fn.stdpath('config') .. "/after")  -- ~/.config/nvim/after