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,FREEMAIL_FROM
	autolearn=ham autolearn_force=no version=3.4.4
X-Google-Thread: 103376,2a34b7ad6c6a0774
X-Google-NewGroupId: yes
X-Google-Attributes: gida07f3367d7,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII
Path: 
 g2news1.google.com!news4.google.com!proxad.net!feeder1-2.proxad.net!usenet-fr.net!gegeweb.org!aioe.org!not-for-mail
From: =?iso-8859-15?Q?Yannick_Duch=EAne_=28Hibou57=29?=
 <yannick_duchene@yahoo.fr>
Newsgroups: comp.lang.ada
Subject: Re: Efficiency of code generated by Ada compilers
Date: Tue, 10 Aug 2010 14:57:32 +0200
Organization: Ada At Home
Message-ID: <op.vg73l6u2xmjfy8@garhos>
References: <f3c0cf89-6993-4b83-b4fe-8a920ce23a14@f6g2000yqa.googlegroups.com>
 <f208e17c-0511-4397-a13a-39a3da6eef5e@q22g2000yqm.googlegroups.com>
 <wccr5i985py.fsf@shell01.TheWorld.com>
 <1jmwhfp.roo31ybayx2bN%csampson@inetworld.net>
 <wcchbj4j09y.fsf@shell01.TheWorld.com>
 <049ff595-3a53-48f3-8001-0d5cf1db0d2a@l6g2000yqb.googlegroups.com>
NNTP-Posting-Host: anOtUalzMUZHasssFqT+2w.user.speranza.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-15; format=flowed; delsp=yes
Content-Transfer-Encoding: Quoted-Printable
X-Complaints-To: abuse@aioe.org
X-Notice: Filtered by postfilter v. 0.8.2
User-Agent: Opera Mail/10.60 (Win32)
Xref: g2news1.google.com comp.lang.ada:13057
Date: 2010-08-10T14:57:32+02:00
List-Id: <comp.lang.ada>

Le Tue, 10 Aug 2010 14:26:25 +0200, Phil Clayton  =

<phil.clayton@lineone.net> a =E9crit:
>   A(A'Length - I - 1)
>
> (not valid Ada, of course.)

A(A'Last - (I - A'First))

> Perhaps "reverse" would be a better name for the operator "not" when
> the modulus is not a power of two?
Or "wrapped" ? But this would only make sens on an array instance basis,=
  =

not on type basis. If the array actual range is not the same as the inde=
x  =

type range, it fails. So this could not be a type primitive (operator). =
 =

May be an array attribute ? A'From_Last ? A'Last_Based ?

"reverse" is already there for loop statements. I feel this makes for se=
ns  =

for loop, as what is reverse, is not the array index: this is the  =

iteration which goes reversed order.

-- =

There is even better than a pragma Assert: a SPARK --# check.
--# check C and WhoKnowWhat and YouKnowWho;
--# assert Ada;
--  i.e. forget about previous premises which leads to conclusion
--  and start with new conclusion as premise.