def p_octets_take_append

bend-osdev-bytes@0.1.1.0 · PROOF.bend:431

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

431def p_octets_take_append(+a: B.Octets, +b: B.Octets) -> {B.Octets.take(B.Octets.len(a), B.Octets.append(a, b)) == a : B.Octets}:
432  match a b:
433    case B.Octets{+xs} B.Octets{+ys}:
434      %F_take(B.w8s.len.fast(xs), B.w8s.append.fast(xs, ys)) : {B.Octets{_} == B.Octets{xs} : B.Octets}
435      %F_len(xs) : {B.Octets{B.w8s.take(_, B.w8s.append.fast(xs, ys))} == B.Octets{xs} : B.Octets}
436      %F_app(xs, ys) : {B.Octets{B.w8s.take(List.length(&2, B.OctByte, xs), _)} == B.Octets{xs} : B.Octets}
437      Equal.cong(List<&2, B.OctByte>, B.Octets, l => B.Octets{l}, B.w8s.take(List.length(&2, B.OctByte, xs), List.append(&2, B.OctByte, xs, ys)), xs, w8s_take_app(xs, ys))