anchor.diff:        (error "No package named ~S." name)))
   
   (defun use-one-package (package-to-use package)
  -  (when (string= (package-name package-to-use) "KEYWORD")
  +  (when (eql package-to-use *keyword-package*)
       (error "Cannot use the KEYWORD package."))
     (pushnew package-to-use (package-use-list package))
     (pushnew package (package-used-by-list package-to-use)))
  
positive.code: 
  (defun keywordp (object)
    (and (symbolp object)
         (eq (symbol-package object) (find-package "KEYWORD"))))
  
  ;;; TODO: shadowing symbols.
  (defun %defpackage (name nicknames documentation use-list import-list export-list intern-list)
  
negative.code: 
  (defvar *package-list* '()
    "The package registry.")
  (defvar *keyword-package* nil
    "The keyword package.")
  
  (defstruct (package
  	     (:constructor %make-package (name nicknames))
  