When enumeration representation clause is too late?

When enumeration representation clause is too late?

[Victor Porton]

When enumeration representation clause is too late and so must be 
disallowed?

From compiler writer's perspective, it is clear that enumeration 
representation clause should not be after calling an enum value.

But I have not found such a rule in the ARM-2012.

-- 
Victor Porton - http://portonvictor.org

Re: When enumeration representation clause is too late?

[J-P. Rosen]

Le 17/08/2014 23:38, Victor Porton a écrit :
> When enumeration representation clause is too late and so must be 
> disallowed?
> 
> From compiler writer's perspective, it is clear that enumeration 
> representation clause should not be after calling an enum value.
> 
> But I have not found such a rule in the ARM-2012.
> 
A representation clause on a type is not allowed after the type is frozen.

Freezing rules are described in 13.14. Advice: choose a good arm-chair
and grab a mug of coffee before you start reading this paragraph.

-- 
J-P. Rosen
Adalog
2 rue du Docteur Lombard, 92441 Issy-les-Moulineaux CEDEX
Tel: +33 1 45 29 21 52, Fax: +33 1 45 29 25 00
http://www.adalog.fr

Re: When enumeration representation clause is too late?

[Shark8]

On 17-Aug-14 23:13, J-P. Rosen wrote:
> Le 17/08/2014 23:38, Victor Porton a écrit :
>> When enumeration representation clause is too late and so must be
>> disallowed?
>>
>>  From compiler writer's perspective, it is clear that enumeration
>> representation clause should not be after calling an enum value.
>>
>> But I have not found such a rule in the ARM-2012.
>>
> A representation clause on a type is not allowed after the type is frozen.
>
> Freezing rules are described in 13.14. Advice: choose a good arm-chair
> and grab a mug of coffee before you start reading this paragraph.

One thing that would be kind of nice is a "deferred" aspect which would 
allow the representation of an enumeration to be specified in the 
private section. -- This would allow the grouping of types and subtypes 
w/o having to intersperse representation clauses between them and also 
keep them in the private section where I believe is their proper place.

NOT CURRENTLY LEGAL ADA:

     Package K is
         Type Device_States is ( Missing, Standby, Ready, Unknown )
         with Deferred;

         Subtype Integrated_Device is Device_States range Standby..Unknown;

     Private
         For Device_States use (
             Missing	=> 2#000#,
             Standby	=> 2#100#,
             Ready	=> 2#101#,
             Unknown	=> 2#111#
           );
     End K;