add Iter::with_numbering(start~: Int)

[hackwaly]

Maybe zip_with_numbering better?

[illusory0x0]

Maybe zip_with_numbering better?

I think with_index would be better.

fn Iter::with_index[A](self : Iter[A]) -> Iter2[Int,A]

[peter-jerry-ye]

What about mapi and eachi?

[hackwaly]

mapi cannot fit my need.

Iter::zip_with_numbering[T](start~: Int = 0) -> Iter[(T, Int)]

[peter-jerry-ye]

Isn't that just a.mapi(fn (index, value) { (value, index + start) } )?

[hackwaly]

Yes, you are right. But you can derive mapi like this a. zip_with_numbering().map(fn { (v, i) => ... }).

[illusory0x0]

use Iter2 we can use for syntaxto iterate index and element, and then use break statement, which eachi cann't do.

use Iter2 can avoid destruct pair, use mapi has to construct pair and destruct pair

[peter-jerry-ye]

1. [Feature Request] impl Iter2 for Iter[(A, B)] #1319
2. the construct pair and destruct pair should be some optimization considered at compiler level