Questions about OPEN

[Rob MacLachlan <RAM@CMU-CS-C.ARPA>]

    I think that I mostly agree with your suggestions, but there are
some areas of confusion:

    What should the semantics of Truename be as compared to
Probe-File?  My original interpretation was:
    (defun truename (file)
      (or (probe-file file)
	  (error "File ~S does not exist." file)))
You seem to want to assign subtly different semantics to the two.

    Under your interpretation of Truename, what is the name returned
when the stream is open for output and the file already existed?  Is it:
 1] The preexisting file?
 2] The new file?
 3] Either one?
 4] Something else?
 5] Undefined?
As we have discussed at length, 2 is impossible in some OS'es.  1 is
probably always possible, but might not be considered the most natural
by everyone.

  Rob