anchor.diff:                                         ((1)   '1-argument)
                                          ((2)   '2-arguments)
                                          ((3)   '3-arguments))
  -                                expression)
  +                                c-expression)
                ((priority      :initform ,priority
                                :reader priority
                                :allocation :class)
  
positive.code:   ;;    ,(condition-expression  self)
    ;;    ,@(when (sub-statement self) (list (sub-statement self))))
    ;;                                       ; c-sexp
    ;; `(,(intern (c-keyword self) "COM.INFORMATIMAGO.LANGUAGES.LINC.C")
    ;;    ,(c-sexp (condition-expression  self))
    ;;    ,@(when (sub-statement self) (list (c-sexp (sub-statement self)))))
    ;;                                       ; generate
  
negative.code:   ;; `(,(class-name (class-of self)) ,(case-value self)
    ;;    ,@(when (sub-statement self) (list (sub-statement self))))
    ;;                                       ; c-sexp
    ;; `(,(c-identifier (c-keyword self)) ,(c-sexp (case-value self))
    ;;    ,@(when (sub-statement self) (list (c-sexp (sub-statement self)))))
    ;;                                       ; generate
    :generate (progn
  