fn filter

use std.stream { filter }

fn nums() -> stream<i32> {
  for i in 1..=6 { yield i }
}

fn main() io {
  var out: List<i32> = []
  for await x in nums() |> filter(x => *x % 2 == 0) { out.push(x) }
  print("{out}")
}

[2, 4, 6]