+redef class FlatString
+
+ redef fun append(s) do return (new RopeString.from(self)) + s
+
+ redef fun prepend(s) do return (new RopeString.from(self)).prepend(s)
+
+ redef fun insert_at(s, pos)
+ do
+ if pos == 0 then return prepend(s)
+ if pos == length then return append(s)
+
+ var l = substring(0,pos)
+ var r = substring_from(pos)
+ var ret: String = new RopeString.from(l)
+ ret += s
+ return ret + r
+ end
+
+end
+