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From: eachus@mitre-bedford.arpa  (Robert I. Eachus)
Subject: Re: What's the difference between...
Date: 16 Feb 93 15:03:55 GMT	[thread overview]
Message-ID: <EACHUS.93Feb16100355@goldfinger.mitre.org> (raw)

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...

             reply	other threads:[~1993-02-16 15:03 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1993-02-16 15:03 Robert I. Eachus [this message]
  -- strict thread matches above, loose matches on Subject: below --
1993-02-16 17:34 What's the difference between John Bollenbacher
1993-02-16 16:17 enterpoop.mit.edu!ira.uka.de!scsing.switch.ch!sicsun!disuns2!lglsun!kipfe
1993-02-15 13:24 cis.ohio-state.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!haven.umd.ed
1993-02-15  1:55 cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sdd.hp.com!portal!cup.portal
1993-02-14 19:55 Adam Beneschan
1993-02-14  3:08 agate!spool.mu.edu!sdd.hp.com!portal!cup.portal.com!R_Tim_Coslet
1993-02-13 19:18 agate!spool.mu.edu!hri.com!noc.near.net!inmet!spock!stt
1993-02-13  5:30 Alex Blakemore
1993-02-12 23:57 Mark A Biggar
1993-02-12 23:51 kronos.arc.nasa.gov!butch!LMSC5.IS.LMSC.LOCKHEED.COM!LJ10891
1993-02-12 22:58 Robert I. Eachus
1993-02-12 18:52 Kenneth Anderson
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