DIP idea: q{}-inspired block mixins

[Stanislav Blinov]

On Wednesday, 10 June 2020 at 03:03:49 UTC, Q. Schroll wrote:

I like it, but I have some Qs for a Q

> Q: Can I use expressions?
> A: Instead of a plain identifier, use [ident = expression()].

Why expression()? I.e. why parentheses?
Evaluated how many times? Eagerly once? Lazily every time 'ident' 
is encountered within the {} ? Lazily once, the first time 
'ident' is encountered within the {}?