I really like the growing interest in making lisps that compile to C, and one that is purely function is even better. I'd be curious how the GC in this compares to the fascinating work in Chicken for novel GC in C environments.
I agree that Chicken is based on a brilliant idea that turned out to work really well in practice. It's a very practical language / implementation.
It is not practical enough for me to have a language which does not support native threads.
And as I read it sometime ago while searching for Scheme implementations with native threads, Cheney on the MTA is inherently single threaded.
Not necessarily, it can be extended to support multithreading: