RFC on range design for D2

[BCS]

Reply to Andrei,

> BCS wrote:
> 
>> Reply to Andrei,
>> 
>>> Hello,
>>> 
>>> Walter, Bartosz and myself have been hard at work trying to find the
>>> right abstraction for iteration. That abstraction would replace the
>>> infamous opApply and would allow for external iteration, thus paving
>>> the way to implementing real generic algorithms.
>>> 
>> First of all, I /Like/ opApply. I know there are issues with it so
>> I'd rather see it supplemented rather than replaced.
>> 
> We all like the way it looks. Ranges will preserve its syntax within a
> much more efficient and expressive implementation.
> 
> Andrei
> 

I was referring to the implementation as visible from the called code's side