Scheme Request for Implementation 227,
"Optional Arguments,"
by Marc Nieper-Wißkirchen (spec and R6RS implementation) and Daphne
Preston-Kendal (R7RS implementation),
has gone into final status.

The document and an archive of the discussion are available at
<https://srfi.schemers.org/srfi-227/>.

Here's the abstract:

This SRFI specifies the opt-lambda syntax, which generalizes lambda.
An opt-lambda expression evaluates to a procedure that takes a number
of required and a number of optional (positional) arguments whose
default values are determined by evaluating corresponding expressions
when the procedure is called.

This SRFI also specifies a variation opt*-lambda, which is to
opt-lambda as let* is to let and the related binding constructs
let-optionals and let-optionals*.

Finally, for those who prefer less explicit procedure definitions, a
sublibrary provides define-optionals and define-optionals*.

Here is the commit summary since the most recent draft:

- Mention define-optionals(*) in the abstract.
- Update abstract.
- copy edits
- Finalize.

Here are the diffs since the most recent draft:

<https://github.com/scheme-requests-for-implementation/srfi-227/compare/draft-2..final>

Many thanks to Marc and to everyone who contributed to the discussion of
this SRFI.

Regards,

SRFI Editor