+SCM
+Rest::brew_molecule (SCM smob)
+{
+ return brew_internal_molecule (smob);
+}
+MAKE_SCHEME_CALLBACK(Rest,extent_callback,2);
+/*
+ We need the callback. The real molecule has ledgers depending on
+ Y-position. The Y-position is known only after line breaking. */
+SCM
+Rest::extent_callback (SCM smob, SCM ax)
+{
+ Axis a = (Axis) gh_scm2int (ax);
+ SCM m = brew_internal_molecule (smob);
+ return ly_interval2scm (unsmob_molecule (m)->extent (a));
+}