From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-help-return-10768-listarch-gcc-help=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 6486 invoked by alias); 22 Nov 2002 18:11:37 -0000
Mailing-List: contact gcc-help-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Archive: <http://gcc.gnu.org/ml/gcc-help/>
List-Post: <mailto:gcc-help@gcc.gnu.org>
List-Help: <mailto:gcc-help-help@gcc.gnu.org>
Sender: gcc-help-owner@gcc.gnu.org
Received: (qmail 6478 invoked from network); 22 Nov 2002 18:11:36 -0000
Received: from unknown (HELO hotmail.com) (64.4.8.123)
  by sources.redhat.com with SMTP; 22 Nov 2002 18:11:36 -0000
Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC;
	 Fri, 22 Nov 2002 10:11:36 -0800
X-Originating-IP: [66.170.45.178]
From: "Buddy Lott" <buddy_lott@hotmail.com>
To: <gcc-help@gcc.gnu.org>
Subject: RE: CPP (preprocessor) quandry
Date: Fri, 22 Nov 2002 10:11:00 -0000
Message-ID: <583E84A77A2FCB4F967E6CD9B0CA4AF74E4906@nt-server.kreuter>
MIME-Version: 1.0
Content-Type: text/plain;
	charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
In-Reply-To: <4.3.2.7.2.20021122114945.00b5eb00@iplan-mn.corp.adobe.com>
Importance: Normal
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106
X-OriginalArrivalTime: 22 Nov 2002 18:11:36.0013 (UTC) FILETIME=[984FB7D0:01C29252]
X-SW-Source: 2002-11/txt/msg00166.txt.bz2

Does it have to work in C or just C++?

It sounds like you are trying to simulate namespaces in c or c++.


Have you you tried something like this

#define NAMESPACE struct y {
#define ENDNAMESPACE }

Then in the code you would do:

NAMESPACE(buddy)

Typedef ...

ENDNAMESPACE

This would also allow you to "customize" name spaces to the whatever the
compiler supports.

> -----Original Message-----
> From: Eljay Love-Jensen [mailto:eljay@adobe.com]
> Sent: Friday, November 22, 2002 1:06 PM
> To: Buddy Lott; gcc-help@gcc.gnu.org
> Subject: RE: CPP (preprocessor) quandry
> 
> Hi Buddy,
> 
> The macro wraps the data type in a struct, so as to reduce namespace
> pollution.
> 
> In particular, it avoids...
> typedef enum {a,b,c} EnumWhatever;
> ...such that a, b, c and EnumWhatever now reside in the global (or
> current)
> namespace.
> 
> I have found a GCC-centric solution.  But (unfortunately) the code
needs
> to
> run on other compilers.
> 
> #define $MkEnum(name$, enum$...) \
> struct name$ {\
>    typedef enum { enum$ } Type;\
>    Type m;\
>    explicit name$ (Type in) : m(in) { }\
>    operator Type () const { return m; };\
>    }
> 
> NOTE: local convention dictates that $ is used to prefix macros
(function
> macros or simple substitution), and $ suffix for the macro's
> parameters.  The $ is digestable by all the preprocessors / compilers
we
> care about.  Less chance of spurious macro vs. local identifier
collision.
> 
> Something similar to this trick was proposed / introduced by
Stroustrup in
> his C++ Programming Language (3rd and Special editions).  Not the
macro
> part, but the wrapping of a POD in a struct to have somewhat stronger
type
> safety.  Getting that stronger type safety is the ultimate purpose of
the
> macros; the macros serve to reduce repetitive typing -- and thus
reduce
> mistakes and simplify maintenance.
> 
> A better solution would be to use a language that has this facility
> native.  Stroupstrup told me (paraphrased), "No one is stopping you
from
> writing your own language."  (I think he was a little tired of hearing
a
> bazillion requests and suggestions for how to "improve" C++.)
> 
> Sincerely,
> --Eljay
> (I hate macros)
> 
> 
> At 12:43 PM 11/22/2002 -0500, Buddy Lott wrote:
> >I can't think of a way to get around this, but maybe if you explain
what
> >purpose this solves (in other wordes, why use the macro) I could
think
> >of a way to accomplish the same thing.
> >
> >One what that comes to mind:
> >
> >Typedef enum { a,b,c} EnumWhatever;
> >MkFoo(Whatever)