anchor.diff:  
   j-> and j->> only take one or two args.  Examples above.
   
  -jbuild takes 1 or more lists as args:
  +JBUILD takes 1 or more lists as args:
   
   If the list starts with a symbol (or quoted symbol) then that is used
   to qualify all the jdoc accesses for the following keys.  Keys may be
  
positive.code: ;;; car 'j-> or 'j->> or 'jbuild gets the expansions shown when
  ;;; used with DEFINE-QUERY.
  
  ;; Of course, we should use the full model name, but :as assignments
  ;; will also work!  maybe build only needs -> ?  Let's assume that for
  ;; now
  
  #|
  sugar                ; S-SQL
  
negative.code:       nil))
  
  (defun nsubst-json-build (sugar tree)
    "Turn SUGAR forms like \(jbuild (\"id\" \"name\"\)\) into the full
  S-SQL :json-build-object function call form inside TREE destructively.
  Acceptable JBUILD syntax is documented in model/user-query.lisp."
    (let ((pairs '()))
      (flet ((nsubst-keys (column keys)
               (dolist (key keys)
  