Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #19151

Re: template metaprogramming in C?

Show all headers | View raw

On 2012-03-29, jacob navia <jacob@spamsink.net> wrote:
> Le 29/03/12 17:30, Nobody a écrit :
>> On Wed, 28 Mar 2012 11:10:52 +0200, jacob navia wrote:
>>
>>>> Looks a lot like macros in Scheme.
>>>>
>>>> Philipp
>>>>
>>>>
>>>
>>> ???
>>> Scheme macros have if/while statements that allow you to generate code
>>> in loops?
>>
>> A Lisp macro is essentially a function which returns Lisp code (a
>> fundamental feature of Lisp is that code is data, making it ideal for
>> metaprogramming). When compiling Lisp functions, macros are expanded by
>> evaluating the macro body and compiling the returned code. Unlike normal
>> function calls, the macro's arguments are passed verbatim (as expressions)
>> rather than being evaluated first.
>>
>
> Then, I am doing exactly that: A meta programming C function is a 
> function that inputs text and outputs text.

Then, you're doing it wrong. Firstly, C is one of the lousiest languages in the
world for metaprogramming.  If you want to do anything "meta" in C,
you don't want to do it in C. Lisp is used for metaprogramming Lisp, not
simply for the sake of making the metaprogramming language the same as
the meta-programmed language. The metaproramming happens because Lisp is an
excellent language for metaprogramming (which evoled along with the 
language right from the beginning).

Look at that GCC MELT project: they are not using C as the meta-programming
language, for good reasons.

Secondly, the Lisp macro is not a text to text mapping. It filters an AST 
data structure to to an AST data structure: it is tree to tree rewriting.  Text
to text mapping is the same as the C preprocessor, or tools like m4.  If you
just want text to text mapping that's better than the preprocessor, just pull
m4 off the shelf.  m4 has all that cruft missing from the C preprocessor, like
looping over lists of things, if/then/else decisions, etc.

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

template metaprogramming in C? Rui Maciel <rui.maciel@gmail.com> - 2012-03-24 11:57 +0000
  Re: template metaprogramming in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-24 07:25 -0700
    Re: template metaprogramming in C? Markus Wichmann <nullplan@gmx.net> - 2012-03-26 11:46 +0200
      Re: template metaprogramming in C? Philipp Klaus Krause <pkk@spth.de> - 2012-03-27 21:09 +0200
        Re: template metaprogramming in C? Markus Wichmann <nullplan@gmx.net> - 2012-03-28 09:25 +0200
          Re: template metaprogramming in C? James Kuyper <jameskuyper@verizon.net> - 2012-03-28 06:59 -0400
      Re: template metaprogramming in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-28 12:13 -0700
      Re: template metaprogramming in C? James Dow Allen <jdallen2000@yahoo.com> - 2012-04-01 02:47 -0700
  Re: template metaprogramming in C? Jens Gustedt <jens.gustedt@loria.fr> - 2012-03-24 18:01 +0100
  Re: template metaprogramming in C? Nobody <nobody@nowhere.com> - 2012-03-24 22:57 +0000
    Re: template metaprogramming in C? William Ahern <william@wilbur.25thandClement.com> - 2012-03-24 18:29 -0700
      Re: template metaprogramming in C? Ian Collins <ian-news@hotmail.com> - 2012-03-25 15:03 +1300
      Re: template metaprogramming in C? nick_keighley_nospam@hotmail.com - 2012-03-25 05:32 -0700
  Re: template metaprogramming in C? BGB <cr88192@hotmail.com> - 2012-03-24 17:02 -0700
  Re: template metaprogramming in C? jacob navia <jacob@spamsink.net> - 2012-03-25 01:21 +0100
    Re: template metaprogramming in C? Philipp Klaus Krause <pkk@spth.de> - 2012-03-27 21:17 +0200
      Re: template metaprogramming in C? jacob navia <jacob@spamsink.net> - 2012-03-28 11:10 +0200
        Re: template metaprogramming in C? Nils M Holm <news2009@t3x.org> - 2012-03-28 10:05 +0000
          Re: template metaprogramming in C? Willem <willem@toad.stack.nl> - 2012-03-28 13:36 +0000
            Re: template metaprogramming in C? Nils M Holm <news2009@t3x.org> - 2012-03-28 14:40 +0000
        Re: template metaprogramming in C? Kaz Kylheku <kaz@kylheku.com> - 2012-03-28 18:32 +0000
          Re: template metaprogramming in C? jacob navia <jacob@spamsink.net> - 2012-03-28 22:27 +0200
            Re: template metaprogramming in C? Kaz Kylheku <kaz@kylheku.com> - 2012-03-28 21:02 +0000
        Re: template metaprogramming in C? Nobody <nobody@nowhere.com> - 2012-03-29 16:30 +0100
          Re: template metaprogramming in C? jacob navia <jacob@spamsink.net> - 2012-03-29 23:39 +0200
            Re: template metaprogramming in C? "BartC" <bc@freeuk.com> - 2012-03-29 23:36 +0100
              Re: template metaprogramming in C? Kaz Kylheku <kaz@kylheku.com> - 2012-03-30 00:55 +0000
            Re: template metaprogramming in C? Kaz Kylheku <kaz@kylheku.com> - 2012-03-30 00:32 +0000
              Re: template metaprogramming in C? "BartC" <bc@freeuk.com> - 2012-03-30 10:52 +0100
                Re: template metaprogramming in C? jacob navia <jacob@spamsink.net> - 2012-04-01 09:36 +0200
            Re: template metaprogramming in C? Ian Collins <ian-news@hotmail.com> - 2012-03-30 16:32 +1300
              Re: template metaprogramming in C? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-31 01:52 -0700
    Re: template metaprogramming in C? ImpalerCore <jadill33@gmail.com> - 2012-03-28 08:48 -0700
      Re: template metaprogramming in C? "io_x" <a@b.c.invalid> - 2012-04-05 12:18 +0200
        Re: template metaprogramming in C? "io_x" <a@b.c.invalid> - 2012-04-05 13:08 +0200
          Re: template metaprogramming in C? "io_x" <a@b.c.invalid> - 2012-04-05 13:36 +0200
            Re: template metaprogramming in C? pete <pfiland@mindspring.com> - 2012-04-06 18:43 -0400
              Re: template metaprogramming in C? pete <pfiland@mindspring.com> - 2012-04-06 19:20 -0400
      Re: template metaprogramming in C? "io_x" <a@b.c.invalid> - 2012-04-05 13:08 +0200
  Re: template metaprogramming in C? William Ahern <william@wilbur.25thandClement.com> - 2012-03-24 19:01 -0700
    Re: template metaprogramming in C? William Ahern <william@wilbur.25thandClement.com> - 2012-03-24 19:10 -0700
  Re: template metaprogramming in C? Ian Collins <ian-news@hotmail.com> - 2012-03-25 15:25 +1300
    Re: template metaprogramming in C? Rui Maciel <rui.maciel@gmail.com> - 2012-03-25 15:13 +0100
      Re: template metaprogramming in C? Ian Collins <ian-news@hotmail.com> - 2012-03-26 07:10 +1300
        Re: template metaprogramming in C? Rui Maciel <rui.maciel@gmail.com> - 2012-03-25 20:31 +0100
          Re: template metaprogramming in C? nick_keighley_nospam@hotmail.com - 2012-03-26 00:54 -0700

csiph-web