anchor.diff:           (if-not-found (elt (lookup this i))
              nil
              (vector-push-extend elt newarr)))
  -      (make-aobj (find-cls :array) newarr)))
  +      (build-array newarr)))
   
     (mth "reverse" ()
       (unless-array (build-array (fvector this))
  
positive.code: 
    (mth "slice" (from to)
      (let* ((len (to-integer (cached-lookup this "length")))
             (newarr (make-array len :fill-pointer 0 :adjustable t))
             (ifrom (to-integer from))
             (from (clip-index (if (< ifrom 0) (+ len ifrom) ifrom) len))
             (ito (if (eq to :undefined) len (to-integer to)))
  
negative.code: 
    (mth "split" (delim)
      (let ((str (to-string this)))
        (if (reobj-p delim)
            (build-array (apply 'fvector (ppcre:split (reobj-scanner delim) str :sharedp t :omit-unmatched-p nil)))
            (let ((delim (to-string delim))
                  (arr (empty-fvector 0)))
              (if (equal delim "")
                  (loop :for ch :across str :do (vector-push-extend (string ch) arr))
                  (loop :for beg := 0 :then (+ pos (length delim))
                        :for pos := (search delim str :start2 beg) :do
                     (vector-push-extend (subseq str beg pos) arr)
                     (unless pos (return))))
              (build-array arr)))))
  
    (mth "concat" (&rest values) ;; TODO 'The length property of the concat method is 1', whatever sense that makes
      (apply #'concatenate 'string (cons (to-string this) (mapcar 'to-string values))))
  