def p_octets_drop_append

bend-osdev-bytes@0.1.1.0 · PROOF.bend:442

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

442def p_octets_drop_append(+a: B.Octets, +b: B.Octets) -> {B.Octets.drop(B.Octets.len(a), B.Octets.append(a, b)) == b : B.Octets}:
443  match a b:
444    case B.Octets{+xs} B.Octets{+ys}:
445      %F_len(xs) : {B.Octets{B.w8s.drop(_, B.w8s.append.fast(xs, ys))} == B.Octets{ys} : B.Octets}
446      %F_app(xs, ys) : {B.Octets{B.w8s.drop(List.length(&2, B.OctByte, xs), _)} == B.Octets{ys} : B.Octets}
447      Equal.cong(List<&2, B.OctByte>, B.Octets, l => B.Octets{l}, B.w8s.drop(List.length(&2, B.OctByte, xs), List.append(&2, B.OctByte, xs, ys)), ys, w8s_drop_app(xs, ys))