// Phase 104 (P2): real-app derived fixture from apps/libs/json_cur.hako:read_digits_from
// Expect numeric output lines: 2 then 1

static box Main {
  read_digits_from(s, pos) {
    local out = ""
    local i = pos
    if i < 0 { return out }

    loop (true) {
      local ch = s.substring(i, i+1)
      if ch == "" { break }
      if ch == "0" || ch == "1" || ch == "2" || ch == "3" || ch == "4" || ch == "5" || ch == "6" || ch == "7" || ch == "8" || ch == "9" { out = out + ch  i = i + 1 } else { break }
    }
    return out
  }

  main() {
    local a = read_digits_from("12x", 0)
    local b = read_digits_from("9", 0)
    print(a.length())
    print(b.length())
    return "OK"
  }
}