On reflection I agree about always allocating bytevectors (including in bytestring-split), so I have created a PR <https://github.com/scheme-requests-for-implementation/srfi-207/pull/12> and I'm requesting Last Call.

On Tue, Oct 20, 2020 at 6:46 PM Wolfgang Corcoran-Mathe <xxxxxx@sigwinch.xyz> wrote:
On 2020-10-20 13:08 -0700, Arthur A. Gleckler wrote:
> Hello, Daphne, John, and Wolfgang, today marks the end of the last-call
> period for SRFI 207.  Have you had time to resolve the issues in Wolfgang's
> message referenced above?

I'd still argue that we should require that the procedures listed in
my previous email return newly-allocated bytevectors in all cases.
An analogous case appears in R7RS with bytevector-append, which must
return a fresh bytevector.  I suggest we follow this example.
Mutation is the soul of bytevector programming, and I'd rather not
introduce nasty surprises in the name of optimizing trivial cases.

Otherwise, I think SRFI 207 looks great.

Regards,

--
Wolfgang Corcoran-Mathe  <xxxxxx@sigwinch.xyz>

"Most learning is not the result of instruction.  It is rather the
result of unhampered participation in a meaningful setting."
--Ivan Illich