+ /// erase the entry at pos and adjust all range bounds past it
+ /// (assumes that a character was deleted at pos)
+ void erase(lyx::pos_type pos);
+
+ /// insert a new entry at pos and adjust all range bounds past it
+ /// (assumes that a character was inserted at pos)
+ void insert(Change const & change, lyx::pos_type pos);
+
+ ///
+
+ /// return the change at the given pos
+ Change const & lookup(pos_type pos) const;