+#include "music.hh"
+#include "context-def.hh"
+#include "global-context.hh"
+
+bool check_grob (Music *mus, SCM sym);
+
+/**
+ There is no real processing to a property: just lookup the
+ translation unit, and set the property.
+*/
+void
+Property_iterator::process (Moment m)
+{
+ SCM sym = get_music ()->get_property ("symbol");
+ if (scm_is_symbol (sym))
+ {
+ SCM val = get_music ()->get_property ("value");
+ bool ok = true;
+ if (val != SCM_EOL)
+ ok = type_check_assignment (sym, val, ly_symbol2scm ("translation-type?"));
+ if (ok)
+ get_outlet ()->internal_set_property (sym, val);
+ }
+ Simple_music_iterator::process (m);
+}
+
+void
+Property_unset_iterator::process (Moment m)
+{
+ SCM sym = get_music ()->get_property ("symbol");
+ type_check_assignment (sym, SCM_EOL, ly_symbol2scm ("translation-type?"));
+ get_outlet ()->unset_property (sym);
+
+ Simple_music_iterator::process (m);
+}
+
+MAKE_SCHEME_CALLBACK (Property_iterator, once_finalization, 2);
+SCM
+Property_iterator::once_finalization (SCM translator, SCM music )
+{
+ Music * m = unsmob_music (music);
+ Context * tg
+ = dynamic_cast<Context *> (unsmob_context (translator));
+ SCM sym = m->get_property ("symbol");
+
+ tg->unset_property (sym);
+ return SCM_UNSPECIFIED;
+}
+
+void
+Property_iterator::do_quit ()
+{
+ if (to_boolean (get_music ()->get_property ("once")))
+ {
+ SCM trans = get_outlet ()->self_scm ();
+ SCM music = get_music ()->self_scm ();
+
+ Global_context * tg = get_outlet ()->get_global_context ();
+ tg->add_finalization (scm_list_n (once_finalization_proc,
+ trans, music, SCM_UNDEFINED));
+ }
+}
+
+
+SCM list_p = 0;
+
+/*
+ This is a rather crude check: we merely check if the translator
+ property is a list.
+ */
+bool
+check_grob (Music *mus, SCM sym)