lib: adds swap_at to arrays

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/standard/collection/array.nit b/lib/standard/collection/array.nit
index 8db629b..e8f7448 100644 (file)
--- a/lib/standard/collection/array.nit
+++ b/lib/standard/collection/array.nit
@@ -212,6 +212,13 @@ class AbstractArray[E]
                        _length = l - 1
                end
        end
+
+       fun swap_at( a : Int, b : Int )
+       do
+           var e = self[a]
+           self[a] = b
+           self[b] = e
+       end
 end
 
 # Resizeable one dimention array of objects.