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From: Nomen Nescio <nobody@dizum.com>
Newsgroups: comp.lang.ada
Subject: Re: Practicalities of Ada for app development
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Date: Sun, 10 Jun 2012 23:36:46 +0200 (CEST)
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Date: 2012-06-10T23:36:46+02:00
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote:
> 
> > Please, why have you defined Code_Point as a modular type?
> 
> Because code point is unsigned. When you declare something signed
> you do that because you want negative inverses. Signed integers have
> the base type with 0 in the middle of its range.

That's no reason to use mod.  You can put boundaries where you want
them, integer, or mod.

It's about the operators.  Mod affects the arithmetic.  If you want
my_type'last + 1 to equal my_type'first, then mod is appropriate.  If
you want the Ada runtime to bitch when you do that, then a unsigned
non-modular discrete type is appropriate.

Choosing a modular type in a case where it doesn't make sense to have
modular arithmetic operators is an abuse of the language.