Re: variable lenght strings

["Randy Brukardt" <randy@rrsoftware.com>]

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"Martin Krischik" <krischik@users.sourceforge.net> wrote in message
news:1154613.ipZcUgduzp@linux1.krischik.com...
> Bj�rn Persson wrote:
>
> > Martin Krischik wrote:
> >> Martin Dowie wrote:
> >>
> >>>Being added in Ada2005, see Ada.Text_IO.Unbounded_IO in
> >>>http://www.ada-auth.org/cgi-bin/cvsweb.cgi/AIs/AI-00301.TXT?rev=1.12
> >>
> >> Cool. How will it handle a missing CR/LF at the end of file?
> >
> > There is a brief discussion of that in the AI file. Randy said that the
> > implementation has always been required to provide an implicit line
> > terminator.
>
> Well, last time i checked GNAT didn't and raised an end of file exception.

My opinion is that GNAT is wrong in that case. A.10(7) makes it quite clear
that you can't have a file terminator without a line and page terminator in
front of it.

I vaguely recall having argued this with Robert Dewar, and I think that they
had a different interpretation, based on the idea that a file with a missing
CR/LF is incorrect for use with Text_IO. I hope I misremember that, because
it is stupid (even if it is logically correct) as it essentially says that
you can't read outside generated text files with Text_IO (you can't know
whether the file has CR/LFs as required).

But I can understand why they wouldn't want to do this properly, because it
is a pain to get right, and it saps the performance of Text_IO (since you
have the be prepared to check for implied characters for each one you read).

                     Randy.