def w8s_take_drop

bend-osdev-bytes@0.1.1.0 · PROOF.bend:190

import Base
import bend-osdev-bytes@0.1.1.0/bytes.bend as B

190def w8s_take_drop(n: Nat, ws: List<&2, B.OctByte>) -> {List.append(&2, B.OctByte, B.w8s.take(n, ws), B.w8s.drop(n, ws)) == ws : List<&2, B.OctByte>}:
191  match n ws:
192    case 0n _:
193      {==}
194    case 1n+p Nil{}:
195      {==}
196    case 1n+p Con{h, t}:
197      %w8s_take_drop(p, t) : {Con{h, List.append(&2, B.OctByte, B.w8s.take(p, t), B.w8s.drop(p, t))} == Con{h, _} : List<&2, B.OctByte>}
198      {==}