!import "base.tri" !Local
!import "list.tri" !Local

nothing = t
just = x : t x

bytesNil? = emptyList?

bytesHead = matchList nothing (h _ : just h)

bytesTail = matchList nothing (_ r : just r)

byteEq? = equal?
bytesLength = length
bytesAppend = append

bytesTake_ = y (self remaining n i :
  matchList
    t
    (h r :
      matchBool
        t
        (pair h (self r n (succ i)))
        (equal? i n))
    remaining)

bytesTake = n bytes : bytesTake_ bytes n 0

bytesDrop_ = y (self remaining n i :
  matchList
    t
    (_ r :
      matchBool
        remaining
        (self r n (succ i))
        (equal? i n))
    remaining)

bytesDrop = n bytes : bytesDrop_ bytes n 0

bytesSplitAt = n bytes : pair (bytesTake n bytes) (bytesDrop n bytes)

bytesEq? = y (self xs ys :
  matchList
    (matchList true (_ _ : false) ys)
    (xh xt :
      matchList
        false
        (yh yt : and? (byteEq? xh yh) (self xt yt))
        ys)
    xs)