Common Lisp 'open'

[Guy Steele <gls@THINK-AQUINAS.ARPA>]

    Date: Wed, 8 Jan 86 20:13:29 est
    From: massar (JP Massar)

    Suppose I have the following:

    (open "x" :direction :output :if-exists :append :if-does-not-exist :create)

    This is fine and dandy unless I don't have permission to write to the file
    and/or create a new file.  Probing the file is of no use, since either the
    file is there and it tells me so or it isn't and it tells me so -- in 
    either case I still want to execute the open.

    It seems like a generic :if-unable-to <retval> construct would be a good
    idea.

    As it is I can see no way or writing robust, portable code that deals with
    files.  I realize that "The opening if files is an area where complete
    portability is too much to hope for", but this seems like a pretty general
    problem (even on a Lispm, I could probe a file, then have the Chaosnet
    go down, and have the open fail on me...).

    Any ideas?  Helpful hints?

What we really need is a Common Lisp error-handling system.
However, I am forwarding this to the Common Lisp mailing list.
--Guy