I've just published draft #4 of SRFI 146.  It was submitted
by Marc Nieper-Wißkirchen, author of the SRFI.

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

Here's the diff:

  <https://github.com/scheme-requests-for-implementation/srfi-146/pull/3>

Here are Marc's comments on this draft:

  Main Changes

  - Remove requirements about SRFI 113 (postpone to future
    SRFI)

  -Add additional procedures for maps with ordered keys

    mapping-min-key
    mapping-max-key
    mapping-min-value
    mapping-max-value
    mapping-key-predecessor
    mapping-key-successor
    mapping-range=
    mapping-range<
    mapping-range>
    mapping-range<=
    mapping-range>=
    mapping-range=!
    mapping-range<!
    mapping-range>!
    mapping-range<=!
    mapping-range>=!
    mapping-split
    mapping-catenate
    mapping-catenate!
    mapping-map/monotone
    mapping-map/monotone!
    mapping-fold/reverse

  Commit Summary

  - updated SRFI 145
  - remove requirements about SRFI 113; mention further SRFIdealing with these questions
  - described new procedures for ordered mappings
  - adjust copyright years
  - fix typo in heading
  - add note about mapping-range=
  - add mapping-catenate to spec
  - implement new procedures for ordered maps
  - Merge branch 'master' of https://github.com/scheme-requests-for-implementation/srfi-146

  File Changes

  - M nieper/rbtree.scm (127)
  - M nieper/rbtree.sld (4)
  - M srfi-146.html (182)
  - M srfi/145.scm (8)
  - M srfi/145.sld (2)
  - M srfi/146.scm (411)
  - M srfi/146/ordered.sld (21)
  - M srfi/146/test.sld (85)

Regards,

SRFI Editor