opMixin or mixin function templates with convenience operator?

[Ola Fosheim Grøstad]

On Thursday, 12 December 2019 at 22:17:59 UTC, Paul Backus wrote:
> If what you actually want is a pure const lambda, there's 
> nothing stopping you from writing one and sticking your mixin 
> inside it.

Just basic software engineering. No external entity should be 
able to access anything in the calling context that has not been 
explicitly exported.

It does not scale well as it can lead to bugs that are hard to 
locate.

So, it is an attempt to mitigate the problematic "macro" aspect 
of mixins and make the construct hygenic.