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.