+void
+Grob::instrumented_set_property (SCM sym, SCM v,
+ char const *file,
+ int line,
+ char const *fun)
+{
+#ifndef NDEBUG
+ if (ly_is_procedure (modification_callback))
+ scm_apply_0 (modification_callback,
+ scm_list_n (self_scm (),
+ scm_from_locale_string (file),
+ scm_from_int (line),
+ scm_from_locale_string (fun),
+ sym, v, SCM_UNDEFINED));
+#else
+ (void) file;
+ (void) line;
+ (void) fun;
+#endif
+
+ internal_set_property (sym, v);
+}
+
+SCM
+Grob::get_property_alist_chain (SCM def) const
+{
+ return scm_list_n (mutable_property_alist_,
+ immutable_property_alist_,
+ def,
+ SCM_UNDEFINED);
+}
+