const data = (
">Rosetta_Example_1
THERECANBENOSPACE
>Rosetta_Example_2
THERECANBESEVERAL
LINESBUTTHEYALLMUST
BECONCATENATED"
)

fn main() {
  mut i := 0
  for i <= data.len {
    if data.substr_ni(i, i + 17) == ">Rosetta_Example_" {
      print("\n" + data.substr_ni(i, i + 18) + ": ")
      i = i + 17
    }
    else {
      if data.substr_ni(i, i + 1) > "\x20" {print(data[i].ascii_str())}
    }
    i++
  }
}