Re: Efficiently setting up large quantities of constant data

[Jeffrey Carter <spam@spam.com>]

Michael Mounteney wrote:

>      type component is
>           record
>                X : character;
>           end record;
> 
>      type component_list is array (positive range <>) of component;
> 
>      type component_ref is access all component_list;

type Component_Ref is access constant Component_List;

> 
>      type structure is
>           record
>                part : component_ref;
>           end record;
> 
> So I will have lots of structures scattered about, which will be
> completely constant.  I would like to enforce this constancy, but Ada
> (as far as I know) does not (unlike C++;  that should get some hackles
> rising) allow `constant' to be splashed about in type definitions. 
> This is on GNAT, which does not support pragma read_only.

It might raise some hackles if it were true.

It sounds, though, as though you can simply write

A_Constant : constant Component_List := (...);

to declare your constants.

-- 
Jeff Carter
"Sir Lancelot saves Sir Gallahad from almost certain temptation."
Monty Python & the Holy Grail
69