I've just published draft #9 of SRFI 146.  It was submitted
by Marc Nieper-Wißkirchen, author of the SRFI.

  <https://srfi.schemers.org/srfi-146/>

Here are Marc's comments on the draft:

  Major changes:

  - New wording on how the uniqueness constraint for the
    mapping type is to be understood.

  - Added the procedures ‘mapping-adjoin’ and
    ‘mapping-adjoin!’ mirroring those from SRFI 113 for
    sets.

  - Emphasized choice of precedence in the constructors
    ‘mapping’ and ‘mapping-unfold’.

  - Small bug fix to sample implementation.

Here's the diff:

  <https://github.com/scheme-requests-for-implementation/srfi-146/compare/fcc352f759ea70eb9def709d5045421a3ef7015c...d188069ecf2351c1422d67505372d503d6ac3b38>

Regards,

SRFI Editor