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From: Brian Rogoff <bpr@shell5.ba.best.com>
Subject: Re: Wanted: Ada STL.  Reward: Ada's Future
Date: 1999/02/03
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Newsgroups: comp.lang.ada
Date: 1999-02-03T00:00:00+00:00
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On Wed, 3 Feb 1999, Matthew Heaney wrote:
> ... snip ...
> 
>   for Index in Map'Range loop
> 
>     <do something with Map (Index)>
> 
>   end loop;
> 
> If this looks simpler than my earlier formulation, that's because it's
> simpler.  Loop iteration in Ada is less error prone than in C.
> 
> This is yet another reason why I think that looking at the STL as a
> model for a standard Ada library is dangerous and misleading.

Indeed. Just look at how incomprehensible AGL looping looks

    Os := Copy(Start(Deque'Access), Finish(Deque'Access), Os);

	or

    Pos := Find(Start(IVec'Access), Finish(IVec'Access), 42);

The horror, the horror ...
 
> The idioms in both languages are completely different.  So forget about
> the STL as a model for an Ada library.

If you do your homework, you'll find that completely independently of C++
or the STL, Judy Bishop wrote a similar library for Ada 83 (trying to
mimic CLU iterators), and it turns out to look remarkably similar to STL or 
AGL. See

Bishop, J.M. et al. "The effect of data abstraction on loop
programming techniques" IEEE TRANSACTIONS ON SOFTWARE ENGINEERING
April 1990. vol.16, no.4, p. 389-402 (Journal Paper - English)

(Note that some of Bishop's complaints about Ada no longer apply to Ada 95)

So far, you've said nothing that indicates that you've looked seriously at 
the STL. Why don't you just get very specific and say exactly why you
think it is a bad model for an Ada library, using examples? I think the
idea of writing algorithms over collections in terms of their iterators is
a good one. 

-- Brian