anchor.diff:  (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 (#:n)
  +(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 (#:=)
  
positive.code: ;;;
  ;;; Parse a main-clause
  
  (defun parse-main-clause (body)
    (parse-alternative body
  		     #'parse-unconditional
  
negative.code:   (if (null body)
        (error 'expected-form-but-end)
        (values (car body) (cdr body))))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  