anchor.diff:  (def-thing
       'user
       (compose #'get-author-data #'get-local-user-id)
  -  #'get-author-representation
  +  #'author-representation-from-row
     :lister (list
              #'user-lister
              :sortkeys '(values id)
  
positive.code: (clack-server-manager
   *handler*
   (clack-pretend:pretend-builder
    (:insert 3) ;clack.builder:builder
    (clack.middleware.clsql:<clack-middleware-clsql>
     :database-type :postgresql-socket3
     :connection-spec *db-connect-spec*)
  
negative.code: (def-db-thing
      'opinion
    'opinion
    (lambda (x)
      (with-output-to-string (s)
        (print x s)))
    :keyfunc (lambda (id)
               (opinion-from-db-row (get-assoc-by-pkey 'opinion id)))
    :sortkeys '(target author datestamp excerpt rooturl))
  