Revised RFC on range design for D2

[Benji Smith]

Andrei Alexandrescu wrote:
> Consider iterating over an array of int[], specifically an int[][]. Then 
> when you call r.head you see the current int[]. You can store it and use 
> it a few steps later or even after the iteration is done for as long as 
> the array is around.
> 
> Contrast that with iterating a file containing lines of integers. The 
> file has a buffer of type int[]. Every time you call r.next, the file 
> range reads a new line, parses the integers, and REFILLS the array with 
> them. If if generated a new array every line, that would cause a great 
> deal of allocations.

Gotcha. I understand now.

Thinking off the top of my head, though, is it actually necessary define 
input ranges as reusing the same array? Wouldn't a peephole optimizer 
get rid of those extra allocations anyhow?

--benji