[boost] Re: Review of Daryle Walker's "More IO" library beginstoday, August 21, 2004.

From: David Abrahams (dave_at_[hidden])
Date: 2004-08-30 12:37:11

"Pavel Vozenilek" <pavel_vozenilek_at_[hidden]> writes:

> "Jonathan Turkanis" wrote:
>
>> >     I believe the attached file does what Pavel has in mind. Let someone
> else
>> > check it, though, since I'm not preprocessor expert.
>>
>> One last try ... the version I just posted had the include guards out of
> order.
>>
>>
> The technique used here is called file iteration. It works well.

Actually that's called "local iteration".

> It is the most powerful mechanism in PP.
>
That's debatable, I guess ;-).  It is cool, though.

>
> The local iteration approach is bit simpler and would look like:
> -------------
> #define BOOST_PP_LOCAL_MACRO( n )                                     \
>     template < BOOST_PP_ENUM_PARAMS(n, typename T) >                   \
>     explicit base_from_member( BOOST_PP_ENUM_BINARY_PARAMS(n, T, x) )  \
>         : member( BOOST_PP_ENUM_PARAMS(n, x) )                         \
>         {}                                                             \
>     /**/
>
> #define BOOST_PP_LOCAL_LIMITS   (1, BOOST_BASE_FROM_MEMBER_MAX_ARITY)
> #include BOOST_PP_LOCAL_ITERATE()
> -------------
>
> I think file iteration makes no harm.
>
> /Pavel
>
>
>
>
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-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com