+bool
+Music_iterator::run_always ()const
+{
+ return false;
+}
+
+bool
+is_child_context (Context *me, Context *child)
+{
+ while (child && child != me)
+ child = child->get_parent_context ();
+
+ return child == me;
+}
+
+/*
+ move to context of child iterator if it is deeper down in the
+ hierarchy.
+*/