anchor.diff:      (loop FOR (file) IN files
             DO (with-open-file (in file :element-type 'uint1)
                  (write-byte (file-length in) out))))
  -  
  +
     ;; write each file content
     (with-open-output-file (out destination 'uint1 :if-exists :append)
       (loop FOR (file) IN files
  
positive.code:     (output:with-output (node node-file :byte-width 8)
        (with-open-output-file (exts exts-file 'uint4)
          (let ((da (make-da :node node :exts exts)))
            (build-impl trie (node-allocator:make) da 
                        (new-node 0 trie)
                        (make-hash-table :test #'eq)
                        show-progress))))
  
negative.code:   (write-node-impl node da))
  
  (defmacro show-and-write-node (node da &key base)
    `(progn
       (incf #1=(da-done-count ,da))
       (when (and show-progress (zerop (mod #1# 100000)))
         (show ";  ~a nodes~%" #1#))
  