opConcatAll?

[jmh530]

On Thursday, 2 July 2020 at 20:29:59 UTC, Steven Schveighoffer 
wrote:
> [snip]
>
> OK, I see what you are saying. And yes, a generalized mechanism 
> to handle this would be useful for both avoiding allocations 
> and avoiding temporaries (among other things).
>
> Nick's idea is pretty good for both.
>
> -Steve

Nick's idea only handles the case where all the operators are the 
same, e.g. a + b + c and not a + b - c.