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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: S-expression I/O in Ada
Date: Mon, 9 Aug 2010 20:17:40 -0500
Organization: Jacob Sparre Andersen
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Date: 2010-08-09T20:17:40-05:00
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:1y1c8zzqmcer5.po56hkesa968.dlg@40tude.net...
...
>> For these, you don't want modular semantics -- you just want
>> a data type whose representation matches what you're
>> interfacing/communicating with, such as "type Octet is
>> range 0..2**8-1;"
>
> The problem is that these things require both array-of-Boolean view and
> arithmetic. I agree that when arithmetic is used, then it has to be wide.
> E.g. when interpreting sequences of octets as little/big endian numbers, 
> we
> never use modular arithmetic. But integer arithmetic is incompatible with
> array/set view.

What have you done with Dmitry?? You can't be the *real* Dmitry! :-)

Array-of-bytes views and arithmetic views are of clearly different types, 
with different sets of operations. These shouldn't be mixed, logically or 
any other way. If you need to go between these views, you need some sort of 
type conversion (or Unchecked_Conversion or Stream'Read or...). Thus, it is 
*never* necessary to do operations on both views at once, and it is 
irrelevant what the "math" operations for octets is. If Ada gets anything 
wrong about this, it is that it has math operations at all for 
stream_elements.

The Dmitry I now certainly understands this, so I wonder what you've done 
with him... :-)

                                    Randy.