Cbor.decode: def of bend-kit-cbor@0.3.0.0
Import: import bend-kit-cbor@0.3.0.0/cbor.bend as Cbor
Lines 779-785 of bend-kit-cbor@0.3.0.0/cbor.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-cbor@0.3.0.0/cbor.bend&start_line=779&end_line=785

import Base
import bend-kit-bytes@0.3.3.0/bytes.bend as Bytes

# One well-formed data item (RFC 8949 §3, Appendix C) filling b. Indefinite strings, arrays and maps come back
# definite, with chunks joined. None for truncation, reserved ai 28..30, a misplaced break or indefinite form,
# a simple value 0..31 in two bytes, text that is not UTF-8, or trailing bytes.
# fuel: a head or chunk eats a byte, and each SDone step follows one, so 2 * len + 2 steps are enough.
def decode(b: Bytes.Bytes) -> Maybe<&1, Val>:
  Bytes.Bytes{+len, buf} = b
  run(Nat.add(Nat.mul(U32.to_nat(len), 2n), 2n), (buf, SHead{0, Nil{}}), len)

Uses (10):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.mul
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Sigma
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.to_nat
  https://jend.leeeet.dev/definition.txt?path=bend-kit-bytes@0.3.3.0/bytes.bend&name=Bytes
  https://jend.leeeet.dev/definition.txt?path=bend-kit-cbor@0.3.0.0/cbor.bend&name=St
  https://jend.leeeet.dev/definition.txt?path=bend-kit-cbor@0.3.0.0/cbor.bend&name=Val
  https://jend.leeeet.dev/definition.txt?path=bend-kit-cbor@0.3.0.0/cbor.bend&name=run