anchor.diff:  ;; RETURN: An input-stream.
   ;; "
   ;;   (etypecase stream
  +;;     (echo-stream         (echo-stream-input-stream  stream))
   ;;     (two-way-stream      (two-way-stream-input-stream stream))
  -;;     (echo-stream         (echo-stream-input-stream  stream))
   ;;     (synonym-stream      (stream-input-stream
   ;;                           (symbol-value (synonym-stream-symbol stream))))
   ;;     (concatenated-stream (stream-input-stream
  
positive.code:         (and therefore usable by #+clisp SOCKET:SOCKET-STATUS).
  "
    (etypecase stream
      (two-way-stream
       (ecase direction
         (:output (bare-stream (two-way-stream-output-stream stream)
                               :direction direction))
         (:input  (bare-stream (two-way-stream-input-stream stream)
                               :direction direction))))
      (echo-stream
       (ecase direction
         (:output (bare-stream (echo-stream-output-stream stream)
                               :direction direction))
         (:input  (bare-stream (echo-stream-input-stream  stream)
                               :direction direction))))
      (synonym-stream
       (bare-stream (symbol-value (synonym-stream-symbol stream))
  
negative.code: ;; RETURN: An output-stream.
  ;; "
  ;;   (etypecase stream
  ;;     (echo-stream     (echo-stream-output-stream  stream))
  ;;     (two-way-stream  (two-way-stream-output-stream stream))
  ;;     (synonym-stream  (stream-output-stream
  ;;                       (symbol-value (synonym-stream-symbol stream))))
  ;;     (t
  