return treeTestNode(level, index, text), true, nil
}
-// viewPush is the push of rollback_state_list.js.
+// viewPush adds state to the newest end of states and returns the new list. An
+// empty list gets one entry. When the newest entry is not kept, it becomes kept
+// with its own state, and state is dropped. When it is kept, state becomes a
+// new newest entry, and the state of the old newest entry goes to the older
+// entries by the same push.
func viewPush(state int, states *ViewPushEntry) *ViewPushEntry {
if states == nil {
return &ViewPushEntry{