-- Iteration 19: Bytes, the binary carrier. Length-carrying, content-
-- comparable, no literal form — built from text or from base64, which is how
-- it will arrive once WebSocket frames and digests exist (iteration 24 and
-- the crypto fork). Text goes back to meaning text.
fn main() {
  let raw = bytes_of_text("writeonce")
  print_int(bytes_len(raw))
  print_int(bytes_at(raw, 0))

  -- slicing is clamped like substr, and produces a fresh Bytes
  let head = bytes_slice(raw, 0, 5)
  print(text_of_bytes(head))
  print(text_of_bytes(bytes_slice(raw, 5, 99)))
  print_int(bytes_len(bytes_slice(raw, 99, 3)))

  -- content equality, not identity
  print_int(bytes_eq(raw, bytes_of_text("writeonce")))
  print_int(bytes_eq(raw, head))

  -- concat
  print(text_of_bytes(bytes_concat(head, bytes_of_text("!"))))

  -- base64 round trip, including the two padding shapes
  print(base64_encode(raw))
  print(base64_encode(bytes_of_text("ab")))
  print(base64_encode(bytes_of_text("a")))
  let back = base64_decode("d3JpdGVvbmNl")
  if back != nil {
    print_int(bytes_eq(back, raw))
  }

  -- binary safety: a NUL byte in the middle survives, which is the whole
  -- reason Text-as-bytes was a hole
  let nul = base64_decode("YQBi")
  if nul != nil {
    print_int(bytes_len(nul))
    print_int(bytes_at(nul, 1))
  }

  -- malformed base64 is nil, not a trap: it arrives from the network
  print_int(base64_decode("!!!!") == nil)
  print_int(base64_decode("abc") == nil)
}