lib/standard/ropes: + operation in O(1) time now

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>

diff --git a/lib/standard/ropes.nit b/lib/standard/ropes.nit
index 9220705..ebc3377 100644 (file)
--- a/lib/standard/ropes.nit
+++ b/lib/standard/ropes.nit
@@ -309,7 +309,18 @@ class RopeString
                return ret
        end
 
-       redef fun +(o) do return insert_at(o.to_s, length)
+       redef fun +(o) do
+               if self.length == 0 then return o.to_s
+               if o.length == 0 then return self
+               var str = o.to_s
+               if str isa FlatString then
+                       return new RopeString.from_root(new Concat(root, new StringLeaf(str)))
+               else if str isa RopeString then
+                       return new RopeString.from_root(new Concat(root, str.root))
+               else
+                       abort
+               end
+       end
 
        redef fun *(n)
        do