Re: [boost] request: BOOST_NO_SFINAE_EXPR macro

Subject: Re: [boost] request: BOOST_NO_SFINAE_EXPR macro
From: Beman Dawes (bdawes_at_[hidden])
Date: 2009-07-31 11:21:10

On Thu, Jul 30, 2009 at 10:20 AM, Mathias
Gaunard<mathias.gaunard_at_[hidden]> wrote:
> It would be very nice if Boost.Config provided the BOOST_NO_SFINAE_EXPR
> macro, that would be defined if the compiler does not support SFINAE applied
> to expressions.
> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2634.html
>
> GCC supports this feature since 4.4 both for C++03 and C++0x for example.

Yes, such a macro is needed

Also, it turns out that the ability to provide a default template
parameter for function templates markedly clarifies code using
enable_if. (I learned this Howard Hinnant, but I think he may have
gotten the idea from Peter Dimov.)

Thus we need a BOOST_NO_DEFAULT_TEMPLATE_ARGUMENT_FOR_FUNCTION_TEMPLATE.
Or maybe BOOST_NO_FUNCTION_TEMPLATE_DEFAULT_PARAMETER. (or is the
correct term "argument"? Need to look that up.

I'm overloaded. If you'd like to submit a patch, that would be great.

Thanks,

--Beman