On Fri, Feb 16, 2018 at 2:28 PM, Steven Watanabe via Boost < boost@lists.boost.org> wrote:
AMDG
On 02/16/2018 01:09 PM, Zach Laine via Boost wrote:
I'm don't understand what that would mean, exactly. What you can write though is:
template
auto operator()(Tag, T &&... t) Is that different from the intended use case above?
There's one annoying problem with this, which is that it can match an expression transform, with Tag as the Expression and T as an empty parameter pack.
Very true, and very annoying. I tend to explicitly cover the possible
arities. They are unary, binary, ternary for if_else, and N for call. I'm
certainly open to something that makes transforms easier to write, if you
or Peter have ideas.
In this case, something like the expression_tag<> scheme Peter recommended
helps with this particular ambiguity:
template