+enum
+{
+ SPACEABLE_STAVES,
+ NONSPACEABLE_STAVES,
+ ALL_STAVES
+};
+
+static SCM
+get_maybe_spaceable_staves (SCM smob, int filter)
+{
+ System *me = dynamic_cast<System *> (Grob::unsmob (smob));
+ Grob *align = Grob::unsmob (me->get_object ("vertical_alignment"));
+ SCM ret = SCM_EOL;
+
+ if (align)
+ {
+ SCM *tail = &ret;
+ extract_grob_set (align, "elements", staves);
+
+ for (vsize i = 0; i < staves.size (); ++i)
+ {
+ bool spaceable = Page_layout_problem::is_spaceable (staves[i]);
+ if (staves[i]->is_live ()
+ && ((filter == ALL_STAVES)
+ || (filter == SPACEABLE_STAVES && spaceable)
+ || (filter == NONSPACEABLE_STAVES && !spaceable)))
+ {
+ *tail = scm_cons (staves[i]->self_scm (), SCM_EOL);
+ tail = SCM_CDRLOC (*tail);
+ }
+ }
+ }
+
+ return ret;
+}
+
+MAKE_SCHEME_CALLBACK (System, get_staves, 1)
+SCM
+System::get_staves (SCM smob)
+{
+ return get_maybe_spaceable_staves (smob, ALL_STAVES);
+}
+
+MAKE_SCHEME_CALLBACK (System, get_spaceable_staves, 1)
+SCM
+System::get_spaceable_staves (SCM smob)
+{
+ return get_maybe_spaceable_staves (smob, SPACEABLE_STAVES);
+}
+
+MAKE_SCHEME_CALLBACK (System, get_nonspaceable_staves, 1)
+SCM
+System::get_nonspaceable_staves (SCM smob)
+{
+ return get_maybe_spaceable_staves (smob, NONSPACEABLE_STAVES);
+}
+