Re: Need help for constrained type

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

On 02/06/2014 09:13 AM, Gerd wrote:
>
> But i would like the indices of Usage_Info running from 0..len - 1 (C-style). But when I write
>
>    type Memory_Block (len : Natural) is
>      record
>        Start_Address : Mem_Addr;
>        Block_Size : Natural;
>        Usage_Info : Mem_Array (0..len-1);
>      end record;

That's what happens when you try to do C in Ada.

Technically, you can't use a discriminant to determine the length of an array, 
only to determine a bound. The 2 are the same only when the lower bound is 1 
(the Ada way). Since what you're supplying is not the length, but the 'Last, so 
you should name it that.

-- 
Jeff Carter
"When Bell Labs were invited to evaluate C against the DoD requirements
[for Ada], they said that there was no chance of C meeting the
requirements of readability, safety, etc. for which we were striving,
and that it should not even be on the list of evaluated languages."
William Whitaker
116