Guile ‘fixes letrec*’ and supports the SRFI. I’m not sure what else you want.
Daphne > On 2 Dec 2023, at 21:42, Marc Nieper-Wißkirchen <marc.nie...@gmail.com> wrote: > > This email of mine hasn't been addressed yet unless I am mistaken: > https://srfi-email.schemers.org/srfi-245/msg/23377654/ > > As this SRFI is lacking a sample implementation, I would like to see proof > that it can be implemented as efficiently as the current body semantics. > Maybe the proof is easy, and I just don't see it. Alternatively, the proof > is hard, but then it is even more critical that we have one. Such proof > should also show the feasibility of adding an efficient check that detects > incorrect use of continuations. > > The SRFI claims R6RS compatibility, but the change* it makes to the R6RS > program body semantics means that SRFI 245 bodies have semantics different > from R6RS program bodies. I recommend removing the change versus R6RS. We > have no example of useful code that would benefit from the twist in the > semantics SRFI 245 adds. Moreover, if SRFI 245 used R6RS semantics, we > wouldn't need the proof I wrote above because we have efficient > implementations of the R6RS semantics, including all checks. > > SRFI 245 says that I suggested the change; what I actually suggested were the > R6RS program body semantics, not the variation that showed up in SRFI 245. > > As the proposed change is pervasive (a "body" is ubiquitous in Scheme), it is > essential to get this right. The R6RS semantics is slightly more > conservative and restrictive, and it is better to err on the safe side. > > Marc > > -- > > (*) Expressions followed by a definition are grouped together with the > definition in SRFI 245; in R6RS, every such expression becomes its own > (dummy) definition. This is relevant when first-class continuations are used. > > Am Do., 30. Nov. 2023 um 06:48 Uhr schrieb Arthur A. Gleckler > <s...@speechcode.com>: > I've just published draft #2 of SRFI 245. It was submitted by Daphne > Preston-Kendal, author of the SRFI. > Here are Daphne's comments on the draft: > One quick new draft before finalization, I hope. > One place has been changed to reflect what R7RS small says about assignment > before definition as well as use before definition. I’ve also added the > support info about S7 and Kawa. > Here is the commit summary: > • Remove stray boilerplate. > • Change formatting of the example > • Explicitly forbid set! before definition as well as use > • Add extra support information > Here's the diff: > https://github.com/scheme-requests-for-implementation/srfi-245/compare/draft-1..draft-2 > Daphne has asked me to announce last call for this SRFI. She believes that it > is ready for finalization, but would like to give reviewers one last chance > to submit corrections and feedback before we finalize it. > In particular, I appeal to anyone reading this to try the sample > implementation, run the tests, and send feedback about your results. > If you're interested in this SRFI, please give your feedback via the SRFI 245 > mailing list before 2023-12-06. After that, assuming that no major revisions > are required, we will declare it final. It is important that we get your > feedback before 2023-12-06. If that deadline is too soon for you, but you > would like to contribute, please let me know so that I can extend the > last-call period. > Regards, > SRFI Editor
