Re: initialize an array (1-D) at elaboration using an expression based on the index?

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

"Shark8" <onewingedshark@gmail.com> wrote in message 
news:d779c161-3199-45ca-87ae-d0501c74e219@26g2000yqv.googlegroups.com...
>> ... having been raised on Algol-W I am delighted to see them come back.
>>
>> Is it their unfamiliarity that disturbs you?
>
> No, not so much.
> I don't see how they are [strictly-speaking] necessary, given that we
> have declare-blocks (which can be arbitrarily-nested).
> Granted, they would make it a lot less verbose in many cases. {BTW, if
> we're going to allow if/then statements inside expressions &
> assignments/initializations then what's keeping us from using case-
> statements too?}

(Yes, Ada2012 has case expressions; coverage checking is important and not 
be be sacrificed just because you are writing an expression.)

You can't write a declare block in a declarative part, inside of a pragma, 
or (for Ada 2012) inside of an aspect specification or expression function. 
The first is a significant problem in Ada 95; you have to write:

                  Max_Value : constant Natural := Boolean'Pos(<some 
expr>)*TRUE_VALUE+
                                                                    Boolean'Pos(not 
<some expr>)*FALSE_VALUE;

In order to get a static conditional expression. To claim that the above is 
at all understandable or readable is BS, plus it duplicates the expression.

                  Max_Value : constant Natural := (if <some expr> then 
TRUE_VALUE else FALSE_VALUE);

is worlds better. And it gets even more fun if you have multiple cases...

                             Randy.