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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: S-expression I/O in Ada
Newsgroups: comp.lang.ada
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Date: Sun, 8 Aug 2010 20:24:13 +0200
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Date: 2010-08-08T20:24:13+02:00
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On Sun, 08 Aug 2010 11:34:23 -0400, Robert A Duff wrote:

> Modular types are evil, and should usually be avoided.

They aren't, modular arithmetic is. I wished to be able to define a modular
types without +,-,*,/, and, or, xor, and have a more decent notation for
S'Succ and S'Pred.

> The index type of an unconstrained array should (almost) never
> be modular.

That is again not their fault. If a subtype of a modular type were modular,
e,g,

   type T is mod 256;
   subtype S is T range 2..10;

   X : S := 10;
begin   
   X := X + 1;  -- The result is 2!

then they could be used as indices.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de