anchor.diff:  (defparameter *command-parser-table* (make-hash-table)
     "Mapping from command names to argument parsing functions.")
   
  -(defvar *unsupplied-argument-maker* (cons nil nil))
  +(defvar *unsupplied-argument-marker* (cons nil nil))
   
   (defvar *command-name-delimiters* '(command-delimiter))
   
  
positive.code: 				    (view textual-view)
  				    &key (default nil defaultp) default-type)
    (let ((command (funcall *command-parser* command-table stream)))
      (cond ((and (null command) defaultp)
  	   (values default default-type))
  	  ((null command)
  	   (simple-parse-error "Empty command"))
  	  (t (values command type)))))
  
  (defmacro define-presentation-to-command-translator
  
negative.code: 	(let ((command (accept `(command :command-table ,command-table)
  			       :stream stream
  			       :prompt nil)))
  	  (if (partial-command-p command)
  	    (progn
  	      (beep)
  	      (format *query-io* "~&Argument ~D not supplied.~&"
  		      (position *unsupplied-argument-marker* command))
  	      nil)
  	    command))
        ((or simple-parse-error input-not-of-required-type)  (c)
  