plugins: Introduce helpers.defaultNullOpts.mkLuaFn (#855)

This allows to avoid calling `mkRaw` on lua functions, as they will get
applied automatically.

This could also help in the future to refactor the use of Lua code to
make it more user-friendly.

plugins/dap/dap-python.nix

@@ -26,7 +26,7 @@ in {
 
     includeConfigs = helpers.defaultNullOpts.mkBool true "Add default configurations.";
 
-    resolvePython = helpers.mkNullOrOption types.str ''
+    resolvePython = helpers.defaultNullOpts.mkLuaFn "null" ''
       Function to resolve path to python to use for program or test execution.
       By default the `VIRTUAL_ENV` and `CONDA_PREFIX` environment variables are used if present.
     '';
@@ -75,7 +75,7 @@ in {
             table.insert(require("dap").configurations.python, ${toLuaObject cfg.customConfigurations})
           '')
           + (optionalString (cfg.resolvePython != null) ''
-            require("dap-python").resolve_python = ${toLuaObject (mkRaw cfg.resolvePython)}
+            require("dap-python").resolve_python = ${toLuaObject cfg.resolvePython}
           '')
           + (optionalString (cfg.testRunner != null) ''
             require("dap-python").test_runner = ${toLuaObject cfg.testRunner};

plugins/dap/dap-ui.nix

@@ -186,7 +186,7 @@ in {
         maxValueLines = helpers.defaultNullOpts.mkInt 100 "Maximum number of lines to allow a value to fill before trimming.";
       };
 
-      selectWindow = helpers.mkNullOrOption types.str ''
+      selectWindow = helpers.defaultNullOpts.mkLuaFn "null" ''
         A function which returns a window to be used for opening buffers such as a stack frame location.
       '';
     };
@@ -212,7 +212,7 @@ in {
           max_value_lines = maxValueLines;
         };
 
-        select_window = helpers.mkRaw selectWindow;
+        select_window = selectWindow;
       }
       // cfg.extraOptions;
   in

plugins/dap/dap-virtual-text.nix

@@ -36,7 +36,7 @@ in {
 
     clearOnContinue = helpers.defaultNullOpts.mkBool false "Clear virtual text on `continue` (might cause flickering when stepping).";
 
-    displayCallback = helpers.defaultNullOpts.mkStr ''
+    displayCallback = helpers.defaultNullOpts.mkLuaFn ''
       function(variable, buf, stackframe, node, options)
         if options.virt_text_pos == 'inline' then
           return ' = ' .. variable.value
@@ -72,7 +72,7 @@ in {
       only_first_definition = onlyFirstDefinition;
       all_references = allReferences;
       clear_on_continue = clearOnContinue;
-      display_callback = helpers.mkRaw displayCallback;
+      display_callback = displayCallback;
       virt_text_pos = virtTextPos;
       all_frames = allFrames;
       virt_lines = virtLines;