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Subject: Re: [boost] [metaparse] Practical usefulness
From: Niall Douglas (s_sourceforge_at_[hidden])
Date: 2015-06-02 21:42:01

On 2 Jun 2015 at 17:42, Michael Caisse wrote:

> > I think back before the C++ 11 STL the question of usefulness was
> > more important than now as Boost becomes more heterogeneous. I note
> > how many reviewers of Metaparse said they are not experts in that
> > field, or would even expect to use Metaparse any time soon
> > themselves.
> Have you ever heard or seen a library like metaparse?

To be honest I had always assumed the concept wasn't feasible as a
practical library. I was very glad to learn I was wrong.

> None of us are experts in the field because I think it is new.

This is ancillory to the argument that it has niche use cases, and
that new C++ libraries have a trend of becoming more specialised and
less general.

> I also think this is exactly the type of library that Boost has been
> known to promote in the past. It is like MPL or Fusion. I'm excited to
> see something like it again.

I am also positive on the library Michael. I had been hoping to give
it an unconditional yes vote in fact, all the boxes were ticked for
me except the silly easy to fix ones.

I think though there is an enormous difference in the C++ field of
practice today compared to pre-Fusion. Before Fusion few of us had
the wisdom to not push C++ as far as it could go. Now we've all been
burned trying to use these fancy libraries in big real world
applications, few of us are itching to repeat that experience. There
has been a big shift back towards simpler is better, and you probably
saw some of that in the recent argumentation about next gen futures
where there was a faction who felt nothing is fundamentally wrong
with present futures, and a faction who think them too big for what
they ought to be. And that's just futures, which are ridiculously
simple compared to anything Eric or you are writing every day, though
I've noticed arguments about library primitives are often the most

It's a big reason I always ask about scalability benchmarking for
compile times and compiler memory use for the major compilers for TMP
libraries. Too few do what Louis did before writing a single line of
finished library where he benchmarked every TMP technique for time
and space so he knew what not to do.

Louis should really write those TMP technique benchmarks into a book
and publish it and make some money for himself. I'm sure that Pearson
editor lady I was talking to at C++ Now would consider such a book,
if not I have some tech publisher who reached out to me not too long
ago somewhere in my records.


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