Peder Holt <peder.holt@gmail.com> writes:
Hi, again. I have done some more tinkering with the compile time constant typeof emulation. It now compiles for VC 6.5,VC 7.0 and GCC 3.4 I have split the one argument constant into two. One per typeof instance, and one to iterate (from 1 to N) down the "type tree". This method also improves on the previous in that when a type T has been deduced using BOOST_TYPEOF, the type is reused when BOOST_TYPEOF is used again.
How could it not be? Templates only have one point of instantiation for any given set of arguments.
Anyhow, I have also implemented a feature for improving on the 64 template depth restriction. Haven't got access to an EDG based compiler, but the implementation worked fine with VC 6.5
I have also looked at the newes implementation of your integral encoding, Arkadiy, and it is basically the same as I am doing. I use one value to encode an integer, with the exception of 0xffffffff and 0xfffffffe, but the side effect is that I can not use arrays to create a size for sizeof. I have to use a struct containing two arrays, and I don't know if this is as portable, so I should perhaps adapt to your way of doing it.
Also, your version of TYPEOF_REGISTER_TEMPLATE_X differs from mine. Where I use TYPEOF_REGISTER_TEMPLATE(some_class,2,(typename,unsigned int)), you use TYPEOF_REGISTER_TEMPLATE_X(some_class,(typename)(unsigned int))
My has the advantage of looking more like a template argument list. Your has the advantage of not having to specify the number of template arguments...
Which one is best?
I haven't had time to do any work on integrating the two solutions yet, my typeof implementation is not mature enough, I guess, as I haven't tested it against any other unfortunate compilers without partial template specialization support. Help on this would be greatly appreciated.
Sounds like integration instead of a big #ifdef switch might be appropriate now (?) -- Dave Abrahams Boost Consulting http://www.boost-consulting.com