I've just published draft #4 of SRFI 148.  It was submitted
by Marc Nieper-Wißkirchen, author of the SRFI.

  <https://srfi.schemers.org/srfi-148/>

Here are Marc's comments on the draft:

  - Added em in macros for letrec and do. (It is not
    necessary with the sample implementation, but necessary
    to be spec-conforming.)

  - Added a paragraph about a recommendation to deprecate em
    in the future when a splicing let(rec)-syntax form will
    be available.

  - Fixed em macro so that it can cope with multiple values.

  - Updated included SRFI 147 implementation.

  - Provide a fast implementation for
    free/bound-identifier=? using er-macro-transformer on
    Chibi to demonstrate that using non-portable low-level
    macros to implement the portable high-level macro system
    of this SRFI makes a lot of sense (running all tests
    showed a speed-up of 40%).

Here's the diff:

  <https://github.com/scheme-requests-for-implementation/srfi-148/compare/ef8377e69db5b6e7a6467810f182c3b48bcd7a9d...08f3579aeb21829b3c4f59c638a305157f189ebc>

Regards,

SRFI Editor