Re: [preprocessor] increase tuple size

From: pavel b (paulus1323_at_[hidden])
Date: 2019-11-06 23:03:16

> I am not sure what you are saying above. Did you extend the number of
> maximum variadic elements, the number of maximum tuple elements, or both
?

Here I changed only the number of maximum variadic elements

> As far as Microsoft C++ only supporting a maximum of 127 macro
> arguments, do you have something which shows that ?

https://docs.microsoft.com/en-us/cpp/cpp/compiler-limits?view=vs-2019

> It should only affect variadic data and not tuples

I am afraid that some tuples-specific files like  tuple/to_list.hpp or
tuple/lo_seq.hpp need to be changed as well

On Tue, Oct 29, 2019 at 3:44 AM Edward Diener via Boost-users <
boost-users_at_[hidden]> wrote:

> On 10/28/2019 8:35 PM, pavel b via Boost-users wrote:
> >
> > Hi,
> >
> >     No, you should not be changing the limits and doing so will not
> >     actually
> >     change anything. If you want more than 64 tuple elements you could
> have
> >     a tuple whose elements themselves are tuples. For instance if you
> >     wanted
> >     256 tuple elements you could program this as a tuple with 64 elements
> >     and each of those elements is a tuple with 4 elements. Or if you
> like a
> >     tuple with 16 elements and each of those elements a tuple of 16
> >     elements. You get the idea.
> >
> >
> > Thank you, good Idea! But in my case it was about the support of an old
> > project, therefore a redesign was not my first choice.
> >
> > Unfortunately, there is only little room for improvement. Microsoft C++
> > compiler, for example, supports only 127 macro arguments. >
> > After extending BOOST_PP_VARIADIC_SIZE and BOOST_PP_VARIADIC_SIZE_I in
> > boost/preprocessor/variadic/size.hpp and defining additional
> > BOOST_PP_VARIADIC_ELEM_[64..125] as in preprocessor/tuple/elem.hpp
> > BOOST_PP_TUPLE_SIZE() and BOOST_PP_TUPLE_ELEM() work with up to 126
> > elemnets.
>
> I am not sure what you are saying above. Did you extend the number of
> maximum variadic elements, the number of maximum tuple elements, or both ?
>
> >
> > BOOST_PP_TUPLE_TO_SEQ() uses internal some additional macro parameters,
> > it supports tuples with up to 124 elemrnts after adding
> > BOOST_PP_TUPLE_TO_SEQ_[65..124] similar to preprocessor/tuple/to_seq.hpp
>
> OK.
>
> >
> > No other boost preprocessor macros were changed/tested.
> >
> > So after a few simple changes, I have succeeded to extend tuple size
> > from 64 to 124 elements. It seems to work under current MSVC, clang and
> > gcc versions.
>
> You really need to enhance the current tests dealing with variadic data
> and tuples so that you can show that variadic data and tuples with 126
> elements will work properly, in order to verify that your changes work
> in all cases.
>
> Also if you would like to create a PR for your changes I will be glad to
> look at it.
>
> As far as Microsoft C++ only supporting a maximum of 127 macro
> arguments, do you have something which shows that ? It should only
> affect variadic data and not tuples.
>
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