Re: variable lenght strings

[Jeffrey Carter <spam@spam.com>]

Randy Brukardt wrote:

> 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.

Shouldn't that be "... without an implied line ..."? Clearly text files 
from external sources can lack the explicit terminators, or we wouldn't 
be having this discussion.

FWIW, ObjectAda 7.2.2 SE gives the same behavior. Get_Line successfully 
reads a non-null line shorter than the string at the end of the file 
without the line-terminator characters, but fails on a null line at the 
same place. I can see the logic of that: If you've just skipped the line 
terminator of the last line, you have the same situation, and an attempt 
to read should raise End_Error.

To get this correct, you have to keep track of what you just read. If 
it's a line or page terminator, you raise End_Error; if not, you return 
a null string.

Is there any chance the ARG could rule on this, one way or another?

Also FWIW, AFAIK PragmARC.Get_Line has been used successfully since 1991 
without ever encountering this situation.

-- 
Jeff Carter
"Help! Help! I'm being repressed!"
Monty Python & the Holy Grail
67