anchor.diff:       (!= (exp-main argdefs alst)
          (? (eq ! 'error)
             !
  -          (nconc ! (nconc (@ [. _. (. '%key ._)] key-args)
  -                          rest-arg))))))
  +          (nconc ! (nconc (mapcar [. _. (. '%key ._)] key-args) rest-arg))))))
   
   (fn argument-expand (fun def vals &key (apply-values? t)
                                          (concatenate-sublists? t)
  
positive.code:                                              apply-values?
                                               concatenate-sublists?
                                               break-on-errors?)
                             (exp-main .def .vals))
                     (. (. nil (argument-expand-0 fun def. vals.
                                                  apply-values?
                                                  concatenate-sublists?
  
negative.code:   (argument-expand fun def nil :apply-values? nil))
  
  (fn argument-expand-values (fun def vals &key (break-on-errors? t))
    (mapcar [? (argument-synonym? _)
               ._
               _]
            (cdrlist (argument-expand fun def vals :break-on-errors? break-on-errors?))))
  