It seems with-fluids* (used by with-parameters*) is still a c function. I am not really sure how that stuff works, but I believe C can (always?) impose continuation barriers of delimited continuations.
If you look at the source of parameterize, with-fluids, with-fluids* (and more?) in boot-9 ther are all using scheme functions, or things defined in the VM, whereas srfi-39 depends on with-fluids* that is defined in fluids.c. If the transform from let to let* extends to with-fluids->with-fluids* it should be a trivial thing to put into boot-9.scm, but I rarely dabble with dynamic environments and whatever is in the documentation is somewhat opaque. Best regards Linus Björnstam On Tue, 11 Feb 2025, at 11:59, W. Kosior via Bug reports for GUILE, GNU's Ubiquitous Extension Language wrote: > Hello, > > I've been experimenting with guile-fibers. I noticed that > `with-parameters*' procedure included as an "extra" in Guile's srfi-39 > creates a continuation barrier. From the documentation it is not clear > that it does so. > > Consider this sample program (which I ran with Guile 3.0.9 and Fibers > 1.0.0, as they are defined in Guix > 2fda889ac992977af7b4cd96d09f737d834e0b2d): > > --8<---------------cut here---------------start------------->8--- > (use-modules (fibers) > (fibers channels) > (srfi srfi-18) > ((srfi srfi-39) #:select (with-parameters*))) > > (define %my-channel > (make-channel)) > > (define %my-param > (make-parameter #f)) > > (define %my-thread > (make-thread (lambda () > (run-fibers (lambda () > (with-parameters* (list %my-param) '(hello) > (lambda () > (put-message %my-channel (%my-param)) > 'ok))))))) > > (thread-start! %my-thread) > > (format #t "message: ~a~%" (get-message %my-channel)) > > (thread-join! %my-thread) > --8<---------------cut here---------------end--------------->8--- > > It prints: > >> Uncaught exception in task: >> In fibers.scm: >> 186:20 6 (_) >> 145:21 5 (_) >> In unknown file: >> 4 (with-fluids* (#<fluid 7f192cf70d70>) (hello) #<procedure >> 100903e0 at <…>) >> In current input: >> 17:35 3 (_) >> In fibers/operations.scm: >> 154:10 2 (perform-operation _) >> In fibers/scheduler.scm: >> 357:6 1 (suspend-current-task _) >> In ice-9/boot-9.scm: >> 1685:16 0 (raise-exception _ #:continuable? _) >> ice-9/boot-9.scm:1685:16: In procedure raise-exception: >> Attempt to suspend fiber within continuation barrier > > But if I use `parameterize' rather than `with-parameters*', no errors > occur. Here's an example of a working program: > > --8<---------------cut here---------------start------------->8--- > (use-modules (fibers) > (fibers channels) > (srfi srfi-18)) > > (define %my-channel > (make-channel)) > > (define %my-param > (make-parameter #f)) > > (define %my-thread > (make-thread (lambda () > (run-fibers (lambda () > (parameterize ((%my-param 'hello)) > (put-message %my-channel (%my-param)) > 'ok)))))) > > (thread-start! %my-thread) > > (format #t "message: ~a~%" (get-message %my-channel)) > > (thread-join! %my-thread) > --8<---------------cut here---------------end--------------->8--- > > It prints: > >> message: hello > > Is it a bug that `with-parameters*' doesn't work equivalently? Or am I > reading the info pages wrong? > > Best :) > Wojtek > > -- > W. Kosior > > website: https://koszko.org/koszko.html > fediverse: https://friendica.me/profile/koszko/profile > PGP fingerprint: E972 7060 E3C5 637C 8A4F 4B42 4BC5 221C 5A79 FD1A
