temporary

data-cursor.go

@@ -23,24 +23,36 @@ type dataCursor struct {
 	currentFunc Functor
 }
 
+func newDataCursor(ctx ExprContext) (dc *dataCursor) {
+	dc = &dataCursor{
+		index: -1,
+		ctx:   ctx.Clone(),
+	}
+	return
+}
+
 func (dc *dataCursor) String() string {
 	return "$(...)"
 }
 
 func (dc *dataCursor) Current() (item any, err error) { // must return io.EOF at the last item
-	if item, err = dc.currentFunc.Invoke(dc.ctx, currentName, []any{}); err == nil && item == nil {
+	ctx := cloneContext(dc.ctx)
+	if item, err = dc.currentFunc.Invoke(ctx, currentName, []any{}); err == nil && item == nil {
 		err = io.EOF
 	}
+	exportObjects(dc.ctx, ctx)
 	return
 }
 
 func (dc *dataCursor) Next() (item any, err error) { // must return io.EOF after the last item
-	if item, err = dc.nextFunc.Invoke(dc.ctx, nextName, []any{}); err == nil {
+	ctx := cloneContext(dc.ctx)
+	if item, err = dc.nextFunc.Invoke(ctx, nextName, []any{}); err == nil {
 		if item == nil {
 			err = io.EOF
 		} else {
 			dc.index++
 		}
+		exportObjects(dc.ctx, ctx)
 	}
 	return
 }