sbcl：行尾格式规范

Question

在clisp中，我可以这样做：

(with-open-file (fred "fred-unix"
                  :direction :output
                  :if-exists :supersede
                  :external-format :unix)
  (format fred "lf only~%"))
(with-open-file (fred "fred-mac"
                  :direction :output
                  :if-exists :supersede
                  :external-format :mac)
  (format fred "cr only~%"))
(with-open-file (fred "fred-dos"
                  :direction :output
                  :if-exists :supersede
                  :external-format :dos)
  (format fred "cr/lf~%"))

sbcl扼杀了这个;它不知道：unix或：mac或：dos。我有什么方法可以在sbcl中做到这一点吗？