Not Plan 9, but lately I've been working in Chicken, which is a lovely pragmatic Scheme for *nix: https://www.call-cc.org/ . Perhaps I should give s9fes a shot as well!
Chicken and Gambit are the most portable "big" Scheme implementations. Both come with a Scheme->C compiler and a separate Scheme interpreter. With luck, it's possible to port them to Plan 9 with modest effort. People have built recent versions of Chicken with compilers smaller than GCC and Clang (it was probably tcc). Gambit should be able to target ANSI C. Both implementations use "green threads".
s9fes and Chibi-Scheme are featherweight by comparison, as is TinyScheme. All probably easy to port to Plan 9.
s7 is another small interpreter that ships in one .c file and is actively maintained. Possibly also easy to port.
------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/T7b0afbefb53189b6-M4bf34da27c83338ce49e8014 Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
