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Common Lisp 'open'
- To: massar@THINK-AQUINAS.ARPA, common-lisp@SU-AI.ARPA
- Subject: Common Lisp 'open'
- From: Guy Steele <gls@THINK-AQUINAS.ARPA>
- Date: Thu, 9 Jan 86 10:45 EST
- Cc: gls@THINK-AQUINAS.ARPA
- In-reply-to: The message of 8 Jan 86 20:13-EST from JP Massar <massar>
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
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.