Scheme Request for Implementation 161,
"Unifiable Boxes,"
by Marc Nieper-Wißkirchen,
is now available for discussion.

Its draft and an archive of the ongoing discussion are available
at <https://srfi.schemers.org/srfi-161/>.

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

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<xxxxxx@srfi.schemers.org>.

Here's the abstract:

  Unifiable boxes are, like the boxes of SRFI 111, objects with a
  single mutable state.  A constructor, predicate, accessor, and
  mutator are provided.

  In addition to the state, an equality predicate and union
  operations (link, union, unify) are provided.  Applying a union
  operation to two unifiable boxes makes the two boxes equal (in
  the sense of the equality predicate).  As a consequence, their
  state will also become identical.  In the case of link and
  union, it will be the state of one of the two unioned boxes.  In
  the case of unify, the state is determined by a supplied
  unification procedure.

Regards,

SRFI Editor