Scheme Request for Implementation 153,
"Immutable ordered sets and bags,"
by John Cowan,
is now available for discussion.

Its draft and an archive of the ongoing discussion are
available at <https://srfi.schemers.org/srfi-153/>.

Here are John's comments on this SRFI:

  This is just the SRFI draft.  The implementation will be a
  thin layer over SRFI 146, which is not yet finalized, so
  it'll be a while before I have a complete version.  In the
  meantime, comments about the API will be useful.

  The main outstanding issue is whether immutable bags
  (multisets) of ordered elements are useful enough to
  provide.  Most of the applications of multisets I can
  think of are about counting things, for which
  linear-update SRFI 113 bags seem like a better idea than
  persistent-style bags.

You can join the discussion of the draft by filling out the
subscription form on that page.

You can contribute a message to the discussion by sending it
to <srfi-153@srfi.schemers.org>.

Regards,

SRFI Editor