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Re: [Gcl-devel] si::info works again on Windows
From: |
Camm Maguire |
Subject: |
Re: [Gcl-devel] si::info works again on Windows |
Date: |
20 Mar 2004 14:09:06 -0500 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 |
Thanks Peter! Mike, work-around aside, is this behavior causing you
problems elsewhere? And if so where?
Take care,
Peter Wood <address@hidden> writes:
> On Fri, Mar 19, 2004 at 03:37:02PM +1000, Mike Thomas wrote:
>
> > I believe that there is a deeper problem READ-LINE which has remained hidden
> > since at least the end of 2002.
> >
> > On Windows READ-LINE at the console doesn't wait for input; it just sees the
> > end of the line after the (READ-LINE) and returns an empty string. I believe
> > this may be CR related and I intend to look into it before Monday, time
> > permitting.
> >
> > If there is some text immediately after the (READ-LINE) it returns that
> > text.
>
> Hi
>
> This has been READ-LINE's behaviour for a long time. I have found
> references to it in the KCL mailing list from 1988! :-)
>
> It's also mentioned in the documentation (in gcl-si) ...
>
> <start quote>
>
> Note that when using line at a time input under unix, input forms will
> always be followed by a #\newline. Thus if you do
>
> >(read-line) "" nil
>
> the empty string will be returned. After lisp reads the (read-line) it
> then invokes (read-line). This happens before it does anything else
> and so happens before the newline character immediately following
> (read-line) has been read. Thus read-line immediately encounters a
> #\newline and so returns the empty string. If there had been other
> characters before the #\newline it would have been different:
>
> <end quote>
>
> It is easy to work around, if you want to discard any chars waiting in
> the input stream and just get user input you can do:
>
> (defun rl ()
> (do ()
> ((not (listen)))
> (read-char-no-hang))
> (read-line))
>
> I don't know if it's a bug, but it probably surprises anybody
> encountering it for the first time.
>
> Regards,
> Peter
>
>
> _______________________________________________
> Gcl-devel mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/gcl-devel
>
>
>
--
Camm Maguire address@hidden
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