FYI, C-level implementation appears to be in src\fun.c, line 7722 as
*scheme_dynamic_wind
Jay,
->dynamic-wind issue
--------------------------
The short answer is the code I'm working on is an implementation of
Harel's hierarchical state machine formalism.
I hesitate to provide a long answer as I fear it would be an imposition
on your time and goodwill. Though I'm happy to provide, if you ask.
After some rewriting, the narrow issue in getting the stateless language
to work for this application is a rewrite of the higher-order primitive
dynamic-wind.
This is the known issue with needing to rewrite higher order functions.
Not a surprise.
Below is the relevant code snippet, but,again, it could be any
arbitrary higher order function
I've grepped the racket/src directory without success
and read 'The Scheme of Things: The June 1992 Meeting- Appendix A" by
Rees and "Contstraining Control" by Friedman and Hayes
but both appear to require redefining call/cc which seems like it might
be problematic unless done in a compatible way with racket and #lang
web-server .
Can you provide any guidance on a re-implementation of dynamic-wind?
Thanks again for the assistance.
#|
Capturing a stateless continuation within context of dynamic wind raises
exception
" Attempt to capture a continuation from within an unsafe context:"
|#
#lang web-server
(require web-server/servlet-env)
(define (main-entry request)
(dynamic-wind
void
(λ () (send/suspend
(lambda (k-url)
(response/xexpr
`(html (body (a ([href ,k-url]) "Hello world!")))))))
void))
(define (start request)
(printf "calling start\n")
(main-entry request))
(serve/servlet start
#:stateless? #t
#:launch-browser? #t)
#|
END CODE
|#
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