doc/developpez/poo/listings/type6_s.nit

   1 abstract class Graph
   2         type NODE: Node
   3
   4         var nodes: Array[NODE] = new Array[NODE]
   5
   6         fun add_node(node: NODE)
   7         do
   8                 nodes.add(node)
   9         end
  10 end
  11
  12 class Node end
  13
  14 class XMLDocument
  15         special Graph
  16
  17         redef type NODE: XMLNode
  18 end
  19
  20 class XMLNode special Node end
  21
  22 var doc = new XMLDocument
  23
  24 doc.add_node(new XMLNode)
  25 #doc.add_node(new Node) # Cet ajout déclenche une erreur de type à la compilation