I've just published draft #6 of SRFI 189. It was submitted by John Cowan, co-author of the SRFI. Note that the summary below also includes much work on the sample implementation by co-author Wolfgang Corcoran-Mathe.

John sent these changes in response to Shiro Kawai's comments in the thread with subject "lisp-values->maybe." (Thank you, Shiro.)

Because of this new draft, I've delayed the end of the last-call period a few days.  Please submit your feedback before 2020-06-13.

Here is the commit summary:

• Begin implementation of Draft 5 changes.
• Minor style improvements.
• Update tests.
• Tests: Print headers, minor style improvements.
• Unfolds now support multiple seeds.
• Simplify some type checks and remove redundant checks.
• Minor refactor of -for-each procedures.
• Implement Draft #5 versions of lisp-values procedures.
• Update tests for values->maybe / either.
• Fix out-of-order internal defines in test. Kill trailing space.
• cleared up default failure procedure for maybe-ref
• typo
• Implement maybe-ref errors.
• Tests: simplify macros.
• proper definition of lisp-values->maybe
• merge
• Publish sixth draft.

Here's the diff:

https://github.com/scheme-requests-for-implementation/srfi-189/compare/draft-5..draft-6

Regards,

SRFI Editor