From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,9ce828272f314121
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news1.google.com!newsread.com!newsprint.newsread.com!news-east.rr.com!news.rr.com!newscon06.news.prodigy.com!prodigy.net!newsfeed-00.mathworks.com!news.mv.net!nntp.TheWorld.com!not-for-mail
From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: output and digits
Date: 20 Apr 2005 09:56:51 -0400
Organization: The World Public Access UNIX, Brookline, MA
Message-ID: <wcc1x95361o.fsf@shell01.TheWorld.com>
References: <d41ars$3eo$1@achot.icm.edu.pl>
 <wccmzrvfs4i.fsf@shell01.TheWorld.com> <d42mue$2tc$1@achot.icm.edu.pl>
NNTP-Posting-Host: shell01.theworld.com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: pcls4.std.com 1114005411 30453 192.74.137.71 (20 Apr 2005 13:56:51
 GMT)
X-Complaints-To: abuse@TheWorld.com
NNTP-Posting-Date: Wed, 20 Apr 2005 13:56:51 +0000 (UTC)
User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2
Xref: g2news1.google.com comp.lang.ada:10609
Date: 2005-04-20T09:56:51-04:00
List-Id: <comp.lang.ada>

"Staszek Goldstein" <goldstei@math.uni.lodz.pl> writes:

> >    type Roman_Digit is ('I','V','X','L','C','D','M');
> >    for Roman_Digit use ('I' => Character'('I')'val,
> >                         'V' => ...);
> >
> > Then Unchecked_Conversion from Roman_Digit to Character will work.
> > Except that you then need to order the Roman_Digits in the same
> > order as in Character: "... is ('C', 'D', ..., 'X')".
> 
> This works (if you correct it slightly to integer(character'pos('I')) - pos
> gives a universal integer!), but changing the order does not seem nice in a
> language like Ada...

Oops.  Yeah, 'Pos is what you want.  But you don't need the conversion
to Integer.

What you *really* want is:

    subtype Roman_Digit is Character
        restricted to ('I','V','X','L','C','D','M'); -- Not Ada!

or perhaps:

    type Roman_Digit is new Character
        restricted to ('I','V','X','L','C','D','M'); -- Not Ada!

Actually, it makes no sense to do arithmetic on roman numerals.
So if I were doing this, I would have two functions, for converting
integers to/from roman numerals represented as Strings.
You only need roman numerals for I/O.  All internal processing
can be done in integers.

That's how you'd do it an any language.

- Bob