I've just published draft #2 of SRFI 158.  It was submitted by John Cowan, co-author of the SRFI.

  <https://srfi.schemers.org/srfi-158/>

Note that this draft includes a reference implementation.

Here are John's comments on the draft:

  1) Rather than adding generator-map, I added

  generator-map->list.  This accepts multiple

  generators, but gmap does not.

  2) The new procedure make-accumulator accepts

  three arguments: a kons procedure that takes the

  current accurmulated object and the current

  state and returns the new state, the initial

  state (knil), and a finalizer that transforms

  the state into the returned value.  However,

  there are no finalizers for the other

  accumulator constructors, most of which are

  wrappers around make-accumulator.

Here's the diff:

  <https://github.com/scheme-requests-for-implementation/srfi-158/compare/a9dfcb23a9eb91693c5101d7d5eab83344d8e5f6...728f83ed563bab6e4527ad6aabdcaac1931e38b0>

Regards,

SRFI Editor