Scheme Request for Implementation 177,
"Portable keyword arguments,"
by Lassi Kortela,
has gone into withdrawn status.

The document and an archive of the discussion are available at https://srfi.schemers.org/srfi-177/.

Here is Lassi's summary of the reasons for withdrawal:

After long and careful exploration of keyword argument systems on this SRFI's mailing list, the SRFI itself is being withdrawn.

While the specification presented in this SRFI accomplishes its goal of portable keyword arguments, and could be used as-is, we were ultimately not satisfied with how it meshes with the rest of Scheme and with Lisp tradition. The keyword call syntax presented here is very unorthodox, wrapping keyword arguments in a sublist at the end of each procedure call. This is unlike every other Lisp dialect out there, all of which splice keyword arguments into the same argument list as ordinary positional arguments.

We also could not find a reasonable way to get rid of the call/kw prefix required in portable code at the start of each keyword procedure call. Several Schemers on the mailing list perceived this prefix as too heavy a requirement for all keyword calls. This would also most likely preclude SRFI 177 from being included in the Large Edition of the R7RS language. Prefixes shorter than call/kw were tried, but were found to be a bit cryptic while not solving the fundamental problem.

Here is the commit summary since the most recent draft:

• Switch to ISO dates.
• Write authors consistently. Write <based-on>.
• Show keywords.
• Use HTML links on HTML pages.
• Mention `bar:` for Gambit and Bigloo
• Explain Chibi's let-keywords
• Update Acknowledgements section
• Add withdrawal notice
• Fix typo
• Add sample code from Shiro
• Add vector-based portable implementation
• Add speed benchmarks
• Fix spelling errors.
• Switch to new SRFI standard header format.
• Withdraw.

Regards,


SRFI Editor