From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.5-pre1 (2020-06-20) on
	ip-172-31-74-118.ec2.internal
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=3.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.5-pre1
Date: 16 Feb 93 15:03:55 GMT
From: eachus@mitre-bedford.arpa  (Robert I. Eachus)
Subject: Re: What's the difference between...
Message-ID: <EACHUS.93Feb16100355@goldfinger.mitre.org>
List-Id: <comp.lang.ada>

In article <75650@cup.portal.com> R_Tim_Coslet@cup.portal.com writes:

 > Well, if you REALLY want this level of control, creat a package with all
 > your types in it and make them PRIVATE and only define the operations
 > that are actually physically correct. Then the compiler catches everything
 > at compile time.

   Actually, for this example the best choice is to use a fixed point
type for Apples.  The only predefined multiply and divide operations
you get (that don't require conversions) are for multplication and
division by integers:

       type Apples is delta 1.0 range 0.0..2.0**31;
       -- Use a smaller delta if you need to slice apples.
       subtype Crates is Integer range 0.0..Integer'LAST;
       -- Could use a type and define * and / for Apples, but then 2 *
       -- Apples would be ambiguous.
       A,T: Apples;
       C: Crates;
     begin
       T := A * C; -- OK;
       T := A * A; -- wrong.
       ..


       
--

					Robert I. Eachus

with Standard_Disclaimer;
use  Standard_Disclaimer;
function Message (Text: in Clever_Ideas) return Better_Ideas is...