fn zip

use std.stream { zip }

fn letters() -> stream<str> {
  for s in ["a", "b"] { yield s }
}
fn nums() -> stream<i32> {
  for i in 1..=5 { yield i }
}

fn main() io {
  var out: List<str> = []
  for await (l, n) in letters() |> zip(nums()) { out.push("{l}{n}") }
  print("{out}")
}

["a1", "b2"]