Re: [boost] [thread] Promote detail::invoke

Subject: Re: [boost] [thread] Promote detail::invoke
From: Agustín K-ballo Bergé (kaballo86_at_[hidden])
Date: 2014-06-16 01:46:42

On 16/06/2014 02:16 a.m., Vicente J. Botet Escriba wrote:
> Le 16/06/14 06:47, Agustín K-ballo Bergé a écrit :
>> Boost.Thread has a great implementation of `invoke` in it's detail
>> namespace. I would like to see this moved outside of Threads, so that
>> other libraries can benefit from it (or course, only if Vicente thinks
>> this is ok). This seems like an ideal candidate for the Detail
>> submodule, as several other libraries have a need for this piece of
>> functionality.
>
> Hi Agustín,
>
> which library would make use of this function?

 From the top of my head, libraries that *could* make use of this 
function are: Function, Bind, Thread, Coroutine?, (upcoming) Fiber, 
Fusion, Phoenix, Spirit...

Whether those libraries *would* make use of it, I don't know. I suspect 
that most would want to as they start working on C++11 support.

I for one would like a consistent handling of Callables whenever it 
makes sense.

> The major problem with the current implementation is that there are a
> lot of corner cases and restrictions for C++98 compilers.

That's to be expected.

>> The implementation relies on `BOOST_THREAD_[RV|FWD]_REF`, which could
>> be replaced by `BOOST_[RV|FWD]_REF`.
> The current state of Boost.Thread (version 2 the default one) needs
> these thread specific `BOOST_THREAD_[RV|FWD]_REF` macros to adapt to the
> Boost.Thread specific emulation on version 2, and so if the invoke
> function in detail don't uses them Boost.Thread could not use it :(

I've missed that in my quick search.

> Agustín, as Boost.Thread would not profit of this (at least not
> immediately), would you mind to do the changes and maintain it?

This is unfortunate, as my goal is to avoid libraries reimplementing 
this since it takes a lot of work to implement `invoke` for anything but 
a highly compliant C++11 compiler.

If there is enough interest, I would gladly adapt it and maintain it. I 
have some experience with it; I have implemented and currently maintain 
a C++03 "with rvalue-refs" version of it here:

https://github.com/K-ballo/hpx/blob/master/hpx/util/invoke.hpp

and a C++11 one here:

https://github.com/eggs-cpp/tupleware/blob/draft/include/eggs/tupleware/detail/invoke.hpp#L78

Regards,
-- 
Agustín K-ballo Bergé.-
http://talesofcpp.fusionfenix.com