anchor.diff:                   :type 'token-iterator)
      form-queue))
   
  +(defun display-prompt (input-stream output-stream)
  +  (when (and (interactive-stream-p input-stream)
  +             (not (listen input-stream)))
  +    (format output-stream "shcl> ")
  +    (finish-output output-stream)))
  +
   (defun restartable-command-iterator (raw-stream form-queue)
     (let* ((stream (debug-char-stream raw-stream))
            (tokens (main-token-iterator stream form-queue))
  
positive.code:               (let ((result (evaluate tree)))
                  (declare (ignorable result))
                  (debug-log 'status "RESULT ~A" result))
              (skip ())))
        (die () (sb-ext:exit :code 1)))))
  
negative.code:   (enable-shell-splice-syntax)
    (let* ((form-queue (make-queue))
           (commands (restartable-command-iterator *standard-input* form-queue)))
      (display-prompt *standard-input* *standard-output*)
      (restart-case
          (do-iterator (tree commands)
            (loop
  