Re: [boost] [yap] Review

On February 14, 2018 4:04:12 PM EST, Zach Laine via Boost wrote:

On Wed, Feb 14, 2018 at 2:44 PM, P F wrote:

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If there are advantages to using mp_assign, maybe this extra noise

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few places is worth it. I still have no idea what the mp_assign advantages are though.

The point is to be able to get rid of `::` at the beginning in `BOOST_YAP_USER_UNARY_OPERATOR_MEMBER(logical_not, ::user_expr)`. If

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user forgets those, you need to have a clear way to tell the user

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to add them, because it may not be obvious from the compiler error without understanding the implementation details.

One way to solve this is to avoid it altogether by not passing a template, which you can try to utilize something like mp_assign.

Another possible solution may be to add a static_assert with a message like “you are passing a type instead of template, you may need to

in a the they need prepend

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:: to the parameter to this macro". I think you can use function overloading to distinguish between a type and a template, but I am not sure.

Ah, I get it now, thanks.

I think I'd rather document better that the :: is required, as opposed to doing more template chicanery. This is both because I want to keep compile times low, and because I don't want to make something that might be brittle in ways I don't fully understand. I'm a metaprogrammer of only moderate skill.

You could prepend :: in the macro. -- Rob (Sent from my portable computation device.)