diff --git a/data-cursor.go b/data-cursor.go
index 26d2705..e4e9027 100644
--- a/data-cursor.go
+++ b/data-cursor.go
@@ -55,15 +55,16 @@ func mapToString(m map[string]Functor) string {
 
 func (dc *dataCursor) String() string {
 	return "$()"
-/*	var sb strings.Builder
-	sb.WriteString(fmt.Sprintf(`$(
-	index: %d,
-	ds:    %s,
-	ctx:   `, dc.index, mapToString(dc.ds)))
-	CtxToBuilder(&sb, dc.ctx, 1)
-	sb.WriteByte(')')
-	return sb.String()
-*/
+	/*
+	   var sb strings.Builder
+	   sb.WriteString(fmt.Sprintf(`$(
+	   index: %d,
+	   ds:    %s,
+	   ctx:   `, dc.index, mapToString(dc.ds)))
+	   CtxToBuilder(&sb, dc.ctx, 1)
+	   sb.WriteByte(')')
+	   return sb.String()
+	*/
 }
 
 func (dc *dataCursor) HasOperation(name string) (exists bool) {
@@ -75,9 +76,9 @@ func (dc *dataCursor) HasOperation(name string) (exists bool) {
 func (dc *dataCursor) CallOperation(name string, args []any) (value any, err error) {
 	if functor, ok := dc.ds[name]; ok && isFunctor(functor) {
 		if functor == dc.cleanFunc {
-			return nil, dc.Clean()
+			return dc.Clean()
 		} else if functor == dc.resetFunc {
-			return nil, dc.Reset()
+			return dc.Reset()
 		} else {
 			ctx := cloneContext(dc.ctx)
 			value, err = functor.Invoke(ctx, name, []any{})
@@ -90,7 +91,7 @@ func (dc *dataCursor) CallOperation(name string, args []any) (value any, err err
 	return
 }
 
-func (dc *dataCursor) Reset() (err error) {
+func (dc *dataCursor) Reset() (success bool, err error) {
 	if dc.resetFunc != nil {
 		if dc.resource != nil {
 			ctx := cloneContext(dc.ctx)
@@ -104,10 +105,11 @@ func (dc *dataCursor) Reset() (err error) {
 	} else {
 		err = errNoOperation(resetName)
 	}
+	success = err == nil
 	return
 }
 
-func (dc *dataCursor) Clean() (err error) {
+func (dc *dataCursor) Clean() (success bool, err error) {
 	if dc.cleanFunc != nil {
 		if dc.resource != nil {
 			ctx := cloneContext(dc.ctx)
@@ -120,6 +122,7 @@ func (dc *dataCursor) Clean() (err error) {
 	} else {
 		err = errors.New("no 'clean' function defined in the data-source")
 	}
+	success = err == nil
 	return
 }