def p_octets_take_drop

bend-osdev-bytes@0.1.1.0 · PROOF.bend:345

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

345def p_octets_take_drop(+n: Nat, +o: B.Octets) -> {B.Octets.append(B.Octets.take(n, o), B.Octets.drop(n, o)) == o : B.Octets}:
346  match o:
347    case B.Octets{+ws}:
348      %F_app(B.w8s.take.fast(n, ws), B.w8s.drop(n, ws)) : {B.Octets{_} == B.Octets{ws} : B.Octets}
349      %F_take(n, ws) : {B.Octets{List.append(&2, B.OctByte, _, B.w8s.drop(n, ws))} == B.Octets{ws} : B.Octets}
350      Equal.cong(List<&2, B.OctByte>, B.Octets, l => B.Octets{l}, List.append(&2, B.OctByte, B.w8s.take(n, ws), B.w8s.drop(n, ws)), ws, w8s_take_drop(n, ws))