anchor.diff:  
   ;;; A parser is a function that takes a list of arbitrary Lisp objects
   ;;; and returns two values, the result of the parse and the remainder
  -;;; of the list that needs to be parsed.  When a parser fails, the
  -;;; second value returned is the same as the the list of Lisp objects
  -;;; that it received as an argument. 
  -
  -;;; Returns a list of clauses parsed by repeated 
  -;;; invocations of the parser.
  +;;; of the list that needs to be parsed.  The second return value is
  +;;; identical to the list of Lisp objects that it received as an
  +;;; argument if and only if the parser failed to parse the list of
  +;;; objects.  In that case, the first return value is not specified.
  +
  +;;; Returns a list of clauses parsed by repeated invocations of the
  +;;; parser.
   (defun parse-sequence (body parser)
     (multiple-value-bind (clause rest1)
         (funcall parser body)
       (if (eq rest1 body)
  -	;; Failed parsing the body according to the parser we recieved. 
  -	;; Indicate failure by returning the empty list and the same
  -	;; body as we recieved as argument. 
  +	;; Failed parsing the body according to the parser we
  +	;; received.  Indicate failure by returning the empty list and
  +	;; the same body as we recieved as argument.
   	(values '() body)
   	;; We succeeded parsing the body according to the parser we
   	;; received.  Parse the remainder of the body recursively, and
  
positive.code:     (if (or (null rest1)
  	    (not (symbol-equal (car rest1) '#:by)))
  	(values (make-instance class-name
  			       :list-form form
  			       :step-fun-form #'cdr)
  		rest1)
  	(multiple-value-bind (step-fun-form rest2)
  	    (parse-form (cdr rest1))
  	  (values (make-instance class-name
  				 :list-form form
  				 :step-fun-form step-fun-form)
  		  rest2)))))
  
  (define-elementary-parser parse-for/as-in body (#:in)
    (parse-for/as-in/on (cdr body) 'for/as-in-list-subclause))
  
  (define-elementary-parser parse-for/as-on body (#:on)
    (parse-for/as-in/on (cdr body) 'for/as-on-list-subclause))
  
  (define-elementary-parser parse-for/as-equals-then body (#:=)
    (multiple-value-bind (form1 rest1)
  
negative.code:      (format stream
  	     "Expected (hash-value other-var), but found: ~s"
  	     (found condition)))))
  
  (define-condition conflicting-stepping-directions (loop-parse-error)
    ()
    (:report
     (lambda (condition stream)
       (format stream
  	     "Conflicting stepping directions."))))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  