Re: [boost] PP lambda?

From: Joel de Guzman (djowel_at_[hidden])
Date: 2003-04-12 19:19:33

Paul Mensonides wrote:
> Joel de Guzman wrote:
> 
>>> And that takes all the fun out of it.  pp-metaprogramming and indeed
>>> template metaprogramming, given the current language, is all about
>>> _manipulation_ of the language.  If you take that away, it is still
>>> very useful, but not as "creative", therefore, not as fun. ;)
>> 
>> It would be nice to experiment on new features such as scopes
>> and true iteration. I think it is also a good idea to *push* the
>> CPP specifications with the future in mind.
> 
> A scoping mechanism is already in being considered (FYI, precisely
> because it 
> *limits* the preprocessor).

Scope, IMO, should be the first priority. For one, I would certainly wish 
to see the BOOST_PP prefix a thing of the past. I always get a mild
headache trying to grok Boost.PP expressions.

... Here's a possible syntax (quoted from CLC++M). I'm sure many
of you are already aware of this, nevertheless...

Francis Glassborow wrote:
> In message <d6651fb6.0304110620.6f41227f_at_[hidden]>, James
> Kanze <kanze_at_[hidden]> writes
>> And although it might sound a bit heretical -- the lack of a
>> preprocessor, or any other means, of making logging and tracing as
>> simple as possible.
> 
> Not heretical these days. We spent time earlier this week in the
> evolution group of WG21 & J16 considering ways to take control of the
> pre-processor to make it work well in C++. Our current thinking is to
> add something like:
> 
> #< // no preprocessor macros can permeate this barrier
> // unless explicitly asked for
> 
> #import XYZ // allow that macro through
> #define ABC 123
> #define FALSE 0
> ...
> #export FALSE
> #> // only explicitly exported macros escape
> 
> IOWs create a mechanism to control the scope of pre-processor macros.

Hmmm.... how about namespaces (or modules) ?  :o)...

#< BOOST_PP // boost PP namespace
    // blah blah blah....
#> 

#< MY_MODULE // my module namespace
    #using BOOST_PP // using boost PP namespace
    // blah blah blah....
#> 

Regards,
-- 
Joel de Guzman
joel at boost-consulting.com
http://www.boost-consulting.com
http://spirit.sf.net