class A {
    def del;
    String toString(){del}
    def whoisThis() { return this }
    def met() { return "I'm the method inside '"+del+"'" }
 }

 def outerdel= new A(del: "outer delegate" )
 def innerdel= new A(del: "inner delegate")

 def cout= {
   assert delegate == outerdel
   assert delegate.whoisThis() == outerdel
   assert delegate.del == "outer delegate"
   assert delegate.met() == "I'm the method inside 'outer delegate'"

   assert whoisThis() == outerdel
   assert del == "outer delegate"
   assert met() == "I'm the method inside 'outer delegate'"

   def cin= {
       assert delegate == innerdel
       assert delegate.whoisThis() == innerdel
       assert delegate.del == "inner delegate"
       assert delegate.met() == "I'm the method inside 'inner delegate'"

       assert whoisThis() == outerdel
       assert del == "outer delegate"
       assert met() == "I'm the method inside 'outer delegate'"
   }

   cin.delegate= innerdel
   cin()
 }

 cout.delegate= outerdel
 cout()