>>> * Gambit/Gerbil, Gauche, Bigloo, Chicken, Cyclone, Chibi all have SRFI 18 in some form.
>>> * Kawa does not - continuations are tricky on JVM, perhaps SRFI 18 too?
>>> * MIT Scheme does not seem to have it.
>>
>> * Larceny does not seem to have it either.

> … and Guile has SRFI-18 support.

> It might be good to also tabulate which Schemes have thread support, even if not SRFI 18, like ChezScheme and Racket.

I'm planning to start a comprehensive series of survey, also covering
non-Scheme Lisp implementations. Shiro, John and I have quite a lot of
existing survey material already. It's just a matter of merging and
extending those surveys.

I didn't find an existing threads survey in John's document repo, but he
has a futures spec inspired by SRFI 18:
<https://bitbucket.org/cowan/r7rs-wg1-infra/src/default/FuturesCowan.md>.

All the thread-related stuff on Shiro's wiki:
<http://practical-scheme.net/wiliki/schemexref.cgi>.