Re: What would you like in Ada202X?

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Mon, 30 Apr 2012 08:40:00 +0200, Michael Rohan <michael@zanyblue.com> a  
écrit:
> Here's another suggestion that will probably upset some people but it's
> something I've run into with generated code: it would be nice to have a
> more general "separate" (I seem to remember a posting on this thread  
> about
> how "separate" was bad!).  What I think would be somewhat useful would be
> to allow separate definitions of initializations, e.g.,
>
>     type Integer_List is array (Positive range <>) of Integer;
>     My_Data : constant Integer_List := (1, 2, 3, 4);
>
> If the data used to do the initialization is OS dependent, or otherwise
> generated, it might be nice to do
>
>     My_Data : constant Integer_List separate;
>
> The separate source could then contain just the generated/OS dependent
> data.

As a practical alternative, you can define per‑platform bodies, and turn  
the constant into a pure function, whose implementation belongs to the  
body. Otherwise, if the matter is that your package interface is to  
explicitly expose platform specific definitions, then that suggest your  
interface is a platform interface, and you may rely on child packages, one  
for each platform. In any case, universal and platform specific  
definitions, should not be mixed, that leads to lack of clarity and  
maintenance troubles.

-- 
“Syntactic sugar causes cancer of the semi-colons.” [1]
“Structured Programming supports the law of the excluded muddle.” [1]
[1]: Epigrams on Programming — Alan J. — P. Yale University