anchor.diff:         (setf (owner (territory game territory)) (player game player))
          (setf (armies (territory game territory)) 1)))))
   
  +(defgeneric reset-movable-armies (game)
  +  (:method ((game game))
  +   (loop for territory being the hash-values in (territories game) do
  +         (setf (movable-armies territory) (armies territory)))))
  +
   (defgeneric move-armies (game from to amount)
     (:method ((game game) origin-key destination-key amount)
      (let ((origin (territory game origin-key))
  
positive.code:      (error "Debe ingresar la cantidad de ejércitos adicionales del territorio")
       ir)
     (owner nil a)
     (armies nil a)))
  
  (defclass* game-map ()
    ((territories (error "Debe especificar los territorios") ir)
  
negative.code:        (error "Los territorios tienen que tener el mismo dueño"))
       (unless (> amount 0)
         (error "No se pueden mover 0 o menos ejércitos"))
       (unless (> (movable-armies origin) amount)
         (error "No hay suficientes ejércitos"))
       (decf (armies origin) amount)
       (decf (movable-armies origin) amount)
       (incf (armies destination) amount))))
  
  (defgeneric place-armies (game where amount)
  