Re: [Boost-users] [preprocessor] Argument list conversion

From: Server Levent Yilmaz (leventyilmaz_at_[hidden])
Date: 2007-06-15 17:34:02

On 6/15/07, Server Levent Yilmaz <leventyilmaz_at_[hidden]> wrote:
>
> Hi,
>
> I have the following fun problem, seemingly simple, but couldn't find the
> trick.
>
> The objective is to convert a given argument list to some other one or
> more useful argument list. Each of the arguments are copied verbatim into
> the other list unless it is specified to be a SPECIAL_TYPE.
>
> For example the following two-argument macro function call:
>
> FUNKY_MACRO( 5, ( double*, SPECIAL_TYPE, const char[], SPECIAL_TYPE, int)
> )
>
> would spit out:
>
> (double*, const char[],          int,  special1, special1);
> (double*,     special1, const char[],  special1,      int, special2,
> special2);
>
> note that, in the first generated tuple SPECIAL_TYPE is replaced by some
> other text, and moved to the end of the tuple. In the second one, same
> replacement occurs and some yet other text is appended repeatedly at the
> end, same number of times as SPECIAL_TYPE appears in the original list.
>
> Any ideas how to do this (or part of it) with the incredibly amazing
> Preprocessor library?
>
> thanks
>
> --
>

I have a related, simpler question:

Given a tuple (or any other container) with arbitrary elements, is there a
way to determine if an element is SPECIAL_TEXT or some other text.  For
example given, ( a, b, SPECIAL_TEXT, c, d ), can we construct (0, 0, 1, 0,
0)?

Levent