anchor.diff:    1)
   
   ;;; ------------------------------------------------------------------------
  -;;;   SORT-SUM
  -;;; ------------------------------------------------------------------------
  -
  -(define-sw-parser-rule :SORT-SUM ()
  -  ;; NOTE: Sort sums are now treated as abbreviations in the rhs of sort defs,
  -  ;;       and cannot be used elsewhere.
  -  (:tuple (1 (:repeat+ :SORT-SUMMAND nil)))
  -  (make-sort-sum 1 ':left-lcb ':right-lcb))
  -
  -(define-sw-parser-rule :SORT-SUMMAND ()
  -  (:tuple "|" (1 :CONSTRUCTOR) (:optional (2 :SLACK-SORT)))
  -  (make-sort-summand 1 2 ':left-lcb ':right-lcb))
  -
  -(define-sw-parser-rule :CONSTRUCTOR ()
  -  :NAME)
  -
  -;;; ------------------------------------------------------------------------
  -;;;   SORT-QUOTIENT
  -;;; ------------------------------------------------------------------------
  -
  -(define-sw-parser-rule :SORT-QUOTIENT ()
  -  ;; NOTE: Sort quotients are now treated as abbreviations in the rhs of sort defs,
  -  ;;       and cannot be used elsewhere.
  -  ;; TODO: [still relevant given above?] In doc: sort-quotient relation is expression, but that's ambiguous -- need tight-expression 
  -  (:tuple (1 :CLOSED-SORT) "/" (2 :TIGHT-EXPRESSION)) ; CLOSED-EXPRESSION?
  -  (make-sort-quotient 1 2 ':left-lcb ':right-lcb) :documentation "Quotient")
  -
  -;;; ------------------------------------------------------------------------
   ;;;   SORT-ARROW
   ;;; ------------------------------------------------------------------------
   
  
positive.code:   (make-sort-arrow 1 2 ':left-lcb ':right-lcb))
  
  (define-sw-parser-rule :ARROW-SOURCE ()
    (:anyof :SORT-SUM :SLACK-SORT))
  
  ;;; ------------------------------------------------------------------------
  ;;;   SORT-PRODUCT
  
negative.code:   ;; could be parsed as a one-element field sort with x of type (Integer | f x).
    ;; But with parens required here, that would need to be {x : (Integer | f x)}
    ;; to get that effect.
    (:tuple "(" (1 :RAW-SUBTYPE) ")")
    1)
  
  (define-sw-parser-rule :RAW-SUBTYPE ()
    ;; This can also be used as a :SORT-DEF-RHS
    (:tuple (1 :SLACK-SORT) "|" (2 :EXPRESSION))
    (make-sort-restriction 1 2 ':left-lcb ':right-lcb) :documentation "Subsort")
  
  ;;; ------------------------------------------------------------------------
  