diff --git a/func-builtins.go b/func-builtins.go
index 6b77c3b..69e231b 100644
--- a/func-builtins.go
+++ b/func-builtins.go
@@ -45,6 +45,10 @@ func intFunc(ctx ExprContext, name string, args []any) (result any, err error) {
 	return
 }
 
+func iteratorFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	return
+}
+
 func ImportBuiltinsFuncs(ctx ExprContext) {
 	ctx.RegisterFunc("isNil", &simpleFunctor{f: isNilFunc}, 1, -1)
 	ctx.RegisterFunc("int", &simpleFunctor{f: intFunc}, 1, -1)