diff --git a/builtin-iterator.go b/builtin-iterator.go
index f475fa0..cf412d1 100644
--- a/builtin-iterator.go
+++ b/builtin-iterator.go
@@ -93,8 +93,8 @@ func runFunc(ctx kern.ExprContext, name string, args map[string]any) (result any
 			params[kern.ParamIndex] = it.Index()
 			params[kern.ParamItem] = item
 
-			localCtx.UnsafeSetVar("_", it.Index())
-			localCtx.UnsafeSetVar("__", item)
+			localCtx.UnsafeSetVar("_", item)
+			localCtx.UnsafeSetVar("__", it.Index())
 
 			abort := false
 			if _, err = op.InvokeNamed(localCtx, iterParamOperator, params); err != nil {