+ I'm not sure what the official rules for glissandi are, but
+ usually the 2nd note of the glissando is "exact", so when playing
+ from the start of the line, there is no need to glide.
+
+ From a typographical p.o.v. this makes sense, since the amount of
+ space left of a note at the start of a line is very small.
+
+ --hwn.
+
+ */
+ if (me->get_bound (LEFT)->break_status_dir ())
+ {
+ Interval_t<Moment> moments = me->spanned_time ();
+ moments [LEFT].grace_part_ = 0;
+ if (moments.length () == Moment (0, 0))
+ me->suicide ();
+ }
+
+ return SCM_UNSPECIFIED;
+}
+
+SCM
+Spanner::get_cached_pure_property (SCM sym, int start, int end)
+{
+ // The pure property cache is indexed by (name start . end), where name is
+ // a symbol, and start and end are numbers referring to the starting and
+ // ending column ranks of the current line.
+ if (scm_hash_table_p (pure_property_cache_) == SCM_BOOL_F)
+ return SCM_UNDEFINED;
+
+ SCM key = scm_cons (sym, scm_cons (scm_from_int (start), scm_from_int (end)));
+ return scm_hash_ref (pure_property_cache_, key, SCM_UNDEFINED);
+}
+
+void
+Spanner::cache_pure_property (SCM sym, int start, int end, SCM val)
+{
+ if (scm_hash_table_p (pure_property_cache_) == SCM_BOOL_F)
+ pure_property_cache_ = scm_c_make_hash_table (17);
+
+ SCM key = scm_cons (sym, scm_cons (scm_from_int (start), scm_from_int (end)));
+ scm_hash_set_x (pure_property_cache_, key, val);
+}
+
+ADD_INTERFACE (Spanner,
+ "Some objects are horizontally spanned between objects. For"
+ " example, slurs, beams, ties, etc. These grobs form a subtype"
+ " called @code{Spanner}. All spanners have two span points"
+ " (these must be @code{Item} objects), one on the left and one"
+ " on the right. The left bound is also the X@tie{}reference"
+ " point of the spanner.",
+
+ /* properties */
+ "normalized-endpoints "
+ "minimum-length "
+ "spanner-broken "
+ "spanner-id "
+ "to-barline "
+ );