+void
+Spanner::pre_init ()
+{
+ break_index_ = (vsize)-1;
+ // This is stupid, but derived_mark may be run before broken_into_
+ // has run its constructor and has a recognizable array size.
+ // So we use break_index_ == -1 as a sentinel.
+ spanned_drul_.set (0, 0);
+ pure_property_cache_ = SCM_UNDEFINED;
+}
+