Re: Have the Itanium critics all been proven wrong?

[Bill Findlay <yaldnif.w@blueyonder.co.uk>]

On 22/08/2012 01:58, in article
keb838pn40uf3pq1536e9b3dptgd57h3se@invalid.netcom.com, "Dennis Lee Bieber"
<wlfraed@ix.netcom.com> wrote:

> On Tue, 21 Aug 2012 23:48:29 +0300, Niklas Holsti
> <niklas.holsti@tidorum.invalid> declaimed the following in
> comp.lang.ada:
> 
>> (I'm cross-posting (I hope) this to comp.lang.ada, since there are
>> questions on how Ada is used.)
>> 
>> On 12-08-21 16:00 , Michael S wrote:
> 
>>> Preface:
>>> According to my understanding, one of the Ada objectives was creating
>>> two languages in one.
>>> The first language intended primarily for complex embedded software,
>>> but also suitable for general-purpose system programming.
>>> The second language intended primarily for big complex application-
>>> level programming, but is also applicable for relatively simple
>>> embedded software and for some system programming tasks.
>> 
>> I've been involved wih Ada for a long time, but I don't remember such a
>> "two languages" thing being discussed. Perhaps it was a topic in the
>> early language definition stages.
>> 
> At least during the AJPO period and MIL-STD/1815A, the Ada
> specification was NO SUBSETS and NO SUPERSETS were permitted to call
> themselves Ada. (This doesn't cover optional annexes, just the core
> language).

Yes.  That was enforced rigorously.  But things are different now.
The Restrictions pragma allows the programmer to exclude features that are
considered inappropriate for a particular application.  So it could be said
that Ada now has 2**N subsets, where N is the number of Restrictions
options.  I don't have an exact count, but N is of the order of 50.

Here are the restrictions I impose on my own code:

   pragma Restrictions(Max_Asynchronous_Select_Nesting => 0);
   pragma Restrictions(Max_Tasks => 0);
   pragma Restrictions(No_Abort_Statements);

The above disallow the concurrency feature so that overheads for concurrency
support are not imposed on my sequential programs.

   pragma Restrictions(No_Implementation_Attributes);
   pragma Restrictions(No_Obsolescent_Features);

These are intended to promote portability and forward compatibility.

-- 
Bill Findlay
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