Re: Processing array subsections, a newbie question.

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

Niklas Holsti wrote:
> 
> if Index_Fst <= Buffer'Last then
>    -- Buffer is not empty, something to be done.
>    loop

OK, we get here with Index_Fst < Buffer'Last.

>       Do_Something(Buffer, Index_Fst, Index_Lst, Ok);

And Do_Something set Ok to True.

>       exit when not Ok;

Do_Something doesn't change Index_Fst, so we get past

>       exit when Index_Fst >= Buffer'Last;

to here. Now the OP's concern, IIUC, is that Index_Lst, which Do_Something sets, 
might be = Buffer'Last = Natural'Last (seems unlikely, but I suspect this is 
simplified from an example in which the index range is more constrained and 
Index_Lst is more likely to be = Index_Subtype'Last). In that case

>       Index_Fst := Index_Lst + 1;

will raise an exception.

So it looks to me as if the correct test is

exit when Index_Lst [>]= Buffer'Last;

(Maybe Brenta meant this, and mistyped it; the variable names are very similar. 
Using _First and _Last might make such an error more obvious.)

-- 
Jeff Carter
"Why don't you bore a hole in yourself and let the sap run out?"
Horse Feathers
49