lib/standard/ropes: Added append method.

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

diff --git a/lib/standard/ropes.nit b/lib/standard/ropes.nit
index 30966ee..b493de9 100644 (file)
--- a/lib/standard/ropes.nit
+++ b/lib/standard/ropes.nit
@@ -151,5 +151,31 @@ class RopeString
 
        redef fun to_s do return self
 
+       # Adds `s` at the end of self
+       fun append(s: String): String
+       do
+               if self.is_empty then return s
+               return new RopeString.from_root(append_to_path(root,s))
+       end
+
+       # Builds a new path from root to the rightmost node with s appended
+       private fun append_to_path(node: RopeNode, s: String): RopeNode
+       do
+               var cct = new Concat
+               if node isa Leaf then
+                       cct.left = node
+                       if s isa FlatString then cct.right = new Leaf(s) else cct.right = s.as(RopeString).root
+               else if node isa Concat then
+                       var right = node.right
+                       if node.left != null then cct.left = node.left.as(not null)
+                       if right == null then
+                               if s isa FlatString then cct.right = new Leaf(s) else cct.right = s.as(RopeString).root
+                       else
+                               cct.right = append_to_path(right, s)
+                       end
+               end
+               return cct
+       end
+
 end