+#include "spanner.hh"
+#include "tie.hh"
+#include "global-context.hh"
+
+/*
+TODO: make matching rest engraver.
+*/
+
+/*
+
+ How does this work?
+
+ When we catch the note, we predict the end of the note. We keep the
+ events living until we reach the predicted end-time.
+
+ Every time process_music () is called and there are note events, we
+ figure out how long the note to typeset should be. It should be no
+ longer than what's specified, than what is left to do and it should
+ not cross barlines.
+
+ We copy the reqs into scratch note reqs, to make sure that we get
+ all durations exactly right.
+*/