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: a07f3367d7,d2a3144038a5a80e
X-Google-Attributes: gida07f3367d7,public,usenet
X-Google-NewGroupId: yes
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news2.google.com!npeer01.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!bigfeed3.bellsouth.net!news.bellsouth.net!border2.nntp.dca.giganews.com!nntp.giganews.com!backlog2.nntp.dca.giganews.com!nntp.brightview.co.uk!news.brightview.co.uk.POSTED!not-for-mail
NNTP-Posting-Date: Sat, 13 Jun 2009 11:13:12 -0500
Newsgroups: comp.lang.ada
Followup-To: comp.lang.ada
From: Robert Matthews <ignored@ramatthews.free-online.co.uk>
Subject: Re: Question on types conversions - operations
Date: Sat, 13 Jun 2009 17:13:35 +0100
References: <4a33cb0b$0$2848$ba620e4c@news.skynet.be>
User-Agent: KNode/0.99.01
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7Bit
Message-ID: <aeKdnW8pnb6FTa7XnZ2dnUVZ8m6dnZ2d@brightview.co.uk>
X-Usenet-Provider: http://www.giganews.com
X-Trace: 
 sv3-FpC4qbbD0I/jLTa9XTJhzg2ZHvT8bZykmGkGeRtTq/b42zrQFHu2BqC+IIkihBgYde7y1W9EHvc3fvp!ZwENBEP2ACl3cNffKjw4TpMzdkDS6HT4bJAuLt7UD39RGIFh3fzzS+CYMuuSohZcKJTVYY50lG8z!8ooHOpHZugxrZ4noyg/XXG7w
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint
 properly
X-Postfilter: 1.3.39
Xref: g2news2.google.com comp.lang.ada:6456
Date: 2009-06-13T17:13:35+01:00
List-Id: <comp.lang.ada>

Olivier Scalbert wrote:

> Hello,
> 
> I have the following three types:
>      type Length is new Float;
>      type Time   is new Float;
>      type Speed  is new Float;
> 
> Suppose I need to compute a speed given a length and a time.
> 
>      L: Length := 100.0;
>      T: Time   :=  10.0;
>      S: Speed;
> 
> How to do that ?
> 
> With S := Speed(Float(L) / Float(T)) ? Mmmm ... not nice.
> 
> With S := Speed(L / Length(T)), I am also not satisfy as I convert a
> time in Length ...
> 
> I am sure you have better ideas !
> 
> Good weekend,
> 
> Olivier

For some software with a LOT of maths, I used:
type Working_Real_Type is digits 16;
(which was big enough for the VAX target).
I would convert the various values (typed in a similar
way to your Length, Time etc) to Working_Real_Type
before using them in the equations. It was certainly
not ideal but it seemed a reasonable compromise between
type safety and the maths.

Robert