use fold expressiong for ensureNodes

src/controls/LevelingSensor/QskSGNodeUtility.h

@@ -4,63 +4,35 @@
 
 namespace QskSGNode
 {
-    enum AppendMode : bool {
+    enum AppendMode
-        Sequential = false,
+    {
-        Recursive = true
+        Sequential,
+        Recursive
     };
 
-    namespace detail
-    {
-        template< AppendMode Mode, typename... Ts >
-        struct append;
-
-        template<>
-        struct append<AppendMode::Recursive>
-        {
-            static void nodes( QSGNode* root )
-            {
-            }
-        };   
-        
-        template<>
-        struct append<AppendMode::Sequential>
-        {
-            static void nodes( QSGNode* root )
-            {
-            }
-        };
-
-        template< typename Child, typename... Children >
-        struct append< AppendMode::Recursive, Child, Children... >
-        {
-            static void nodes( QSGNode* root )
-            {
-                auto* const child = new Child;
-                root->appendChildNode( child );
-                append< AppendMode::Recursive, Children... >::nodes( child );
-            }
-        };
-
-        template< typename Child, typename... Children >
-        struct append< AppendMode::Sequential, Child, Children... >
-        {
-            static void nodes( QSGNode* root )
-            {
-                auto* const child = new Child;
-                root->appendChildNode( child );
-                append< AppendMode::Sequential, Children... >::nodes( root );
-            }
-        };
-    }
-
     template< AppendMode mode, typename Root, typename... Children >
     inline Q_REQUIRED_RESULT Root* ensureNodes( QSGNode* root = nullptr )
     {
         if ( root == nullptr )
         {
-            root = new std::remove_const_t<Root>();
+            root = new Root;
-            detail::append< mode, Children... >::nodes( root );
         }
+        
+        if constexpr ( mode == Recursive )
+        {
+            QSGNode* current = root;
+            (
+                [ & ]( QSGNode* const child ) {
+                    current->appendChildNode( child );
+                    current = child;
+                }( new Children ),
+                ... );
+        }
+        else
+        {
+            ( root->appendChildNode( new Children ), ... );
+        }
+
         return static_cast< Root* >( root );
     }
 }