anchor.diff:  definitions in readtables listed earlier.  Notice that the /readtable
   case/ is also subject of the merge operation."
     (flet ((merge-into (rt1 rt2)
  -	   (%with-readtable-iterator (rt2-iter rt2)
  +	   (with-readtable-iterator (rt2-iter rt2)
   	     (loop
   	      (multiple-value-bind (more? char reader-fn disp? table) (rt2-iter)
   		(unless more? (return))
  
positive.code: ;;; readtable (and thus rendering this readtable to be non-standard,
  ;;; in fact.)
  
  (define-condition simple-style-warning (simple-warning style-warning)
    ())
  
  (defun simple-style-warn (format-control &rest format-args)
    (warn 'simple-style-warning
  	 :format-control format-control
  	 :format-arguments format-args))
  
  (defun constant-standard-readtable-expression-p (thing)
    (cond ((symbolp thing) (or (eq thing 'nil) (eq thing :standard)))
  
negative.code: 	 (read-table-name (readtable-name read-table)))
      ;; We use the internal functions directly to omit repeated
      ;; type-checking.
      (%unassociate-name-from-readtable read-table-name read-table)
      (%unassociate-readtable-from-name read-table-name read-table)
      (%associate-name-with-readtable new-name read-table)
      (%associate-readtable-with-name new-name read-table)
      read-table))
  
  (defun merge-readtables-into (result-table &rest named-readtable-designators)
  