anchor.diff:    "Clone the array of children.
   If DEEP is non-NIL, each child is cloned as per (CLONE-NODE NODE T).
   When copying deeply, you can also pass a NEW-PARENT to set on each child."
  -  (loop with array = (make-array (length (children node)) :adjustable T :fill-pointer 0)
  +  (loop with array = (make-child-array (length (children node)))
           for child across (children node)
           do (vector-push (if deep
                               (let ((child (clone-node child T)))
  
positive.code:   ()
    (:documentation "Base DOM node class."))
  
  (defclass nesting-node (node)
    ((%children :initarg :children :initform (make-child-array) :accessor children :type vector))
    (:documentation "Node class that can contain child nodes."))
  (setf (documentation 'children 'function) "Returns a vector of child-nodes that are contained within the node.")
  
  (defclass child-node (node)
    ((%parent :initarg :parent :initform (error "Parent required.") :accessor parent :type (or null node)))
    (:documentation "Node class that is a child and thus has a parent."))
  
negative.code:     (format stream "~@[~a~]" (tag-name node)))
    node)
  
  (declaim (ftype (function (&optional fixnum) (and (vector plump:child-node) (not simple-array))) make-child-array))
  (defun make-child-array (&optional (size 0))
    "Creates an array to contain child elements"
    (make-array size :adjustable T :fill-pointer 0 :element-type 'child-node))
  
  (declaim (ftype (function (&optional fixnum) (and (vector plump:child-node) (not simple-array))) ensure-child-array))
  (defun ensure-child-array (array)
    "If the ARRAY is suitable as a child-array, it is returned.
  Otherwise the array's elements are copied over into a proper
  