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From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2003-10-12 06:32:06

David Abrahams wrote:
> Daniel Frey <daniel.frey_at_[hidden]> writes:
>>smallest issue, I think the separation of components (with separate
>>documentation!) is much more important. Having template-traits is
>>nice, but when they are hidden inside MPL and not documented, they
>>are close to useless for me.
> But Aleksey didn't consider it part of MPL's charter to provide that
> in a way that you could use it.

Of course, I guess the MPL was already enough work in its current form :)

> Likewise, I have indirect_traits.hpp
> in boost/python/detail, with things like is_reference_to_constant. If
> someone else is willing to go to the effort to factor it out, document
> it and take it through (mini) review, then everyone else can use it.
> Otherwise, and until then, it remains hidden.

Depending on my time, I might try to do that. But there are other things
to do before that :)

>>Look at the history of enable_if: It was developed several times
>>independently IIUC and just now we are giving it the attention it
>>deserves as a valuable technique on it's own.
> Not quite; it was developed once by Jaakko et al (**); they wrote a
> paper on it, and people implemented their technique several times in
> Boost.

I wasn't clear on that, sorry. I meant the implementation, not the
technique itself. We already known that besides the basic technique
there's usually a bunch of work-arounds needed for various compilers. A
single implementation helps to cope with that and scales better than
independent implementations.

> Oh, and BTW, I'm not advocating sticking enable_if into MPL.

I think that even Gennadiy just asked whether it makes sense instead of
advocating for it strongly. Seems we all agree on that point :)

> At the same time, if a library author needs a component to get his job
> done, and writes it, he shouldn't feel compelled to put that component
> through a separate review if it's not part of his mission. Template
> traits or whatever you're calling them falls into that category.

I understand that you want to prevent further burdon on the authors, but
I am already content if they at least consider factoring out generally
useful parts. OK, enough bandwidth wasted. :)

Regards, Daniel

Daniel Frey
aixigo AG - financial training, research and technology
Schloß-Rahe-Straße 15, 52072 Aachen, Germany
fon: +49 (0)241 936737-42, fax: +49 (0)241 936737-99
eMail: daniel.frey_at_[hidden], web:

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