anchor.diff:  ;;; ------------------------------------------------------------------------
   
   (define-sw-parser-rule :LAMBDA-FORM ()
  -  (:tuple (:anyof "fn" "\\_lambda") (1 :MATCH))
  +  (:tuple (:anyof "fn" "\\_lambda") (:optional "|") (1 :AUX-MATCH))
     (make-lambda-form 1 ':left-lcb ':right-lcb)
     :documentation "Lambda abstraction")
   
  
positive.code: ;;; ------------------------------------------------------------------------
  
  (define-sw-parser-rule :CASE-EXPRESSION ()
    (:tuple "case" (1 :EXPRESSION) "of" (2 :MATCH))
    (make-case-expression 1 2 ':left-lcb ':right-lcb)
    :documentation "Case statement")
  
  
negative.code: ;;  (list . 1))
  
  (define-sw-parser-rule :MATCH ()
    (:anyof
     (:tuple "|" (1 :AUX-MATCH))
     (:tuple "of" (1 :AUX-MATCH))
     (:tuple "of"  "|" (1 :AUX-MATCH)))
    1)
  
  (define-sw-parser-rule :AUX-MATCH ()
  