I still have a number of comments from when the previous version was
published (which I didn't find time to post then). I will see that I
post them soon.

For example, lefts should definitely be able to hold more than one
value if we want to model Haskell's Either type completely but also
for other reasons.

Marc

Am Di., 2. Juni 2020 um 20:43 Uhr schrieb Arthur A. Gleckler
<xxxxxx@speechcode.com>:
>
> I've just published draft #4 of SRFI 189. It was submitted by John Cowan, co-author of the SRFI.
>
> Here are John's comments on the draft:
>
> I think this is ready for last call now. Wolfgang's implementation will catch up shortly.
>
> Note that I am waiting to announce last call until the implementation and tests are complete.
>
> Here is the commit summary:
>
> fold functions accept all values plus nil
> Implement Draft #3 of SRFI 189 (multiple values).
> Remove maybe-contains? and either-contains?.
> clarified -sequence operations
> maybe->list mutation is an error
> Update -sequence functions.
> Remove tests for -contains procedures.
> Update test sets: predicates, accessors, join and bind.
> Delete "obj" argument in either-remove and -filter.
> Update test sets: sequence operations, conversions.
> Fix arity error in either->lisp-values.
> Update test set for map, fold, unfold.
> Return unspecified value from -for-each procedures.
> Fix typos in definition of maybe-if.
> Improve the bargain basement SRFI 78 implementation.
> Comment cleanup and improvement.
> Add tests for `maybe-if'.
> Refactor some tests for readability.
> style typos
> Lefts now contain exactly one value
> Show keywords.
> Use HTML links on HTML pages.
> Fix typo. Publish fourth draft.
>
> Here's the diff:
>
> https://github.com/scheme-requests-for-implementation/srfi-189/compare/draft-3..draft-4
>
> Regards,
>
>
> SRFI Editor