anchor.diff:    (:shadow :load :eval :package :restart :print :write)
     (:export :run :*argv* :*main* :quit :script :quicklisp :getenv :opt
              :ignore-shebang :roswell :exec :setenv :unsetenv
  -           :with-lock-held))
  +           :with-lock-held)
  +  (:documentation "Roswell backend."))
   
   (in-package :ros)
   (defvar *verbose* 0)
  
positive.code:   (cl:load file))
  
  (defun run (list)
    (loop :for elt :in list
       :do (apply (intern (string (first elt)) (find-package :ros)) elt)))
  
  
negative.code: 
  (defun quit (&optional (return-code 0) &rest rest)
    (let ((ret (or (and (numberp return-code) return-code) (first rest) 0)))
      (ignore-errors (funcall (read-from-string "asdf::quit") ret))
      ;; below are for those environments which lacks neither asdf or uiop.
      #+sbcl (ignore-errors (funcall (read-from-string "cl-user::exit") :code ret))
      #+sbcl (ignore-errors (funcall (read-from-string "cl-user::quit") :unix-status ret))
      #+clisp (ext:exit ret)
      #+ccl (ccl:quit ret)))
  
  (defun run-program (args &key output)
    (if (ignore-errors #1=(read-from-string "uiop/run-program:run-program"))
  