diff --git a/operator-post-inc.go b/operator-post-inc.go
index 8413d30..0def83e 100644
--- a/operator-post-inc.go
+++ b/operator-post-inc.go
@@ -18,19 +18,21 @@ func newPostIncTerm(tk *Token) *term {
 }
 
 func evalPostInc(ctx ExprContext, self *term) (v any, err error) {
-	var leftValue any
-	if leftValue, err = self.evalPrefix(ctx); err != nil {
+	var childValue any
+	if childValue, err = self.evalPrefix(ctx); err != nil {
 		return
 	}
 
-	if dc, ok := leftValue.(*dataCursor); ok {
-		v, err = dc.Next()
-	} else if isInteger(leftValue) && self.children[0].symbol() == SymIdentifier {
-		v = leftValue
-		i, _ := leftValue.(int64)
+	// if dc, ok := leftValue.(*dataCursor); ok {
+	// 	v, err = dc.Next()
+	if it, ok := childValue.(Iterator); ok {
+		v, err = it.Next()
+	} else if isInteger(childValue) && self.children[0].symbol() == SymIdentifier {
+		v = childValue
+		i, _ := childValue.(int64)
 		ctx.SetVar(self.children[0].source(), i+1)
 	} else {
-		self.errIncompatibleType(leftValue)
+		err = self.errIncompatibleType(childValue)
 	}
 	return
 }