@@ -1453,6 +1453,9 @@ impl SessionContext {
             RegisterFunction::Window(f) => {
                 self.state.write().register_udwf(f)?;
             }
+            RegisterFunction::HigherOrder(f) => {
+                self.state.write().register_higher_order_function(f)?;
+            }
             RegisterFunction::Table(name, f) => self.register_udtf(&name, f),
         };
 
@@ -2162,6 +2165,8 @@ pub enum RegisterFunction {
     Aggregate(Arc<AggregateUDF>),
     /// Window user defined function
     Window(Arc<WindowUDF>),
+    /// Higher-order user defined function
+    HigherOrder(Arc<dyn HigherOrderUDF>),
     /// Table user defined function
     Table(String, Arc<dyn TableFunctionImpl>),
 }