From: "Matthew Goulet" <blueherring0@gmail.com>
Subject: Re: Conditional compilation of debug traces without cpp
Date: 6 Jul 2006 22:00:47 -0700
Date: 2006-07-06T22:00:47-07:00 [thread overview]
Message-ID: <1152248447.796179.305520@s13g2000cwa.googlegroups.com> (raw)
In-Reply-To: 44ad719c$0$5389$626a54ce@news.free.fr
guillaume.portail@grospied.enanglais.com wrote:
> Jean-Pierre Rosen wrote:
>
> > Therefore yes, the *execution* of the call will always involve the
> > *evaluation* of the parameters (unless the compiler can prove that this
> > evaluation has no side-effects - like a call to a function declared in a
> > pure package).
>
> Ah yes, I just read LRM95-10.2.1(18), it seems to be what I want (I
> forgot this point). But Pure is applicable only to library units. And I
> need to apply it to functions of packages :
>
> package Data is
> type T is private
> procedure ...
> private
> type T is ...
> end;
>
> package Data.Image
> subtype T_String is String(...);
> function "+" (R : T) return T_String;
> ...
> end;
>
>
> - Data.Image."+" has really no side effect, but it cannot be declared
> Pure. Why ? The legality of such a pragma seems statically computable
> (the body of "+" should not access 'global' variables, etc).
> - "+" is located in its own package, where UI resources are grouped, as
> to facilitate their potential elimination/counting (all are named
> *.*...*.Image).
Perhaps I misunderstand what you are saying, but declaring the packages
Pure means that the functions and procedures in them are also Pure.
So, if Data and Data.Image were Pure, so should "+", even though pragma
Pure cannot be applied to "+" directly.
There is also the new pragma Pure_Function, but I cannot recall off the
top of my head if it can be used outside of the context of a pure
package.
-Matt
next prev parent reply other threads:[~2006-07-07 5:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-04 18:06 Conditional compilation of debug traces without cpp guillaume.portail
2006-07-04 19:07 ` Ludovic Brenta
2006-07-04 19:14 ` guillaume.portail
2006-07-04 21:39 ` Björn Persson
2006-07-04 21:43 ` guillaume.portail
2006-07-04 22:01 ` Björn Persson
2006-07-05 3:10 ` Matthew Goulet
2006-07-04 20:24 ` Gautier
2006-07-04 20:54 ` Simon Wright
2006-07-05 13:03 ` Jean-Pierre Rosen
2006-07-05 19:39 ` guillaume.portail
2006-07-06 5:53 ` Martin Krischik
2006-07-07 10:32 ` Stephen Leake
2006-07-07 14:08 ` M E Leypold
2006-07-06 7:59 ` Jean-Pierre Rosen
2006-07-06 20:25 ` guillaume.portail
2006-07-07 5:00 ` Matthew Goulet [this message]
2006-07-07 13:57 ` Thierry Bernier
2006-07-07 21:08 ` Randy Brukardt
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