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=-2.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,
	MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no
	version=3.4.4
X-Google-Thread: 103376,400766bdbcd86f7c
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news1.google.com!proxad.net!usenet-fr.net!enst.fr!melchior!cuivre.fr.eu.org!melchior.frmug.org!not-for-mail
From: Duncan Sands <baldrick@free.fr>
Newsgroups: comp.lang.ada
Subject: Re: This can't be done in Ada...or?
Date: Sat, 12 Feb 2005 14:55:12 +0100
Organization: Cuivre, Argent, Or
Message-ID: <mailman.138.1108216526.527.comp.lang.ada@ada-france.org>
References: <1108139611.709714.36170@o13g2000cwo.googlegroups.com>
	<xtadnQ1DlL2teJHfRVn-qw@comcast.com>
	<wcck6pf54w0.fsf@shell01.TheWorld.com>
NNTP-Posting-Host: lovelace.ada-france.org
Mime-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
X-Trace: melchior.cuivre.fr.eu.org 1108216527 1504 212.85.156.195 (12 Feb 2005
 13:55:27 GMT)
X-Complaints-To: usenet@melchior.cuivre.fr.eu.org
NNTP-Posting-Date: Sat, 12 Feb 2005 13:55:27 +0000 (UTC)
Cc: comp.lang.ada@ada-france.org
To: Robert A Duff <bobduff@shell01.TheWorld.com>
Return-Path: <baldrick@free.fr>
In-Reply-To: <wcck6pf54w0.fsf@shell01.TheWorld.com>
X-Mailer: Evolution 2.0.2 
X-Virus-Scanned: by amavisd-new-20030616-p10 (Debian) at ada-france.org
X-BeenThere: comp.lang.ada@ada-france.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "Gateway to the comp.lang.ada Usenet newsgroup"
	<comp.lang.ada.ada-france.org>
List-Unsubscribe: <http://www.ada-france.org/mailman/listinfo/comp.lang.ada>,
	<mailto:comp.lang.ada-request@ada-france.org?subject=unsubscribe>
List-Post: <mailto:comp.lang.ada@ada-france.org>
List-Help: <mailto:comp.lang.ada-request@ada-france.org?subject=help>
List-Subscribe: <http://www.ada-france.org/mailman/listinfo/comp.lang.ada>,
	<mailto:comp.lang.ada-request@ada-france.org?subject=subscribe>
Xref: g2news1.google.com comp.lang.ada:8278
Date: 2005-02-12T14:55:12+01:00

> The compiler can optimize away everything inside the "if
> Logging_Enabled".  But it can't optimize away the evaluation of the
> parameters unless it can prove the absence of side effects.
> For example:
> 
>     Trace.Error(..., "Bad value of X " & Debug_Info(X));
> 
> where Debug_Info is some user-defined function that produces useful
> debug info about some complicated data structure called X.
> It has no side effects, but the compiler doesn't know that, usually.

GNAT's pragma Pure_Function might help here.  Is something like that
planned for Ada 2005?

All the best,

Duncan.