Re: Raise expressions from AARM.

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

On 2024-02-24 10:50, Blady wrote:
> 
> My guess: whatever the size of Some_Array (greater than 3), B is elaborated but 
> raises Not_Valid_Error when accessing component beyond position 3:
> 
> type Some_Array is array (Positive range 1..10) of Natural;
> ...
> B : Some_Array := (1, 2, 3, others => raise Not_Valid_Error);
> ...
> begin
> X := B (2); -- OK
> X := B (6); -- raises Not_Valid_Error
> end;
> 
> Is it correct?

No. This will raise the exception upon the elaboration of B.

The only use of this that I can imagine is if the length of Some_Array is 3. 
Then the others choice is null, so the raise expression is never evaluated. But 
if someone changes the definition of Some_Array to be longer, then the exception 
will be raised.

> NB: GNAT 13.2 issues a compilation error:
>          >>> error: "others" choice not allowed here
> see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113862

The example in the error report has Some_Array unconstrained, in which case an 
others choice is not allowed. With the constrained definition given above, the 
aggregate is valid.

-- 
Jeff Carter
"Gentlemen, you can't fight in here. This is the War Room!"
Dr. Strangelove
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