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.
If you find Lisp to C compilers interesting, then Common Lisp has a bunch for you. The first CL to C compiler was KCL (Kyoto Common Lisp from Japan in the mid 80s). It is the parent for several other compilers.
Gnu Common Lisp, Embeddable Common Lisp, mkcl, mocl.
There are also attempts at C++ as a target language. See CLASP.
Cool, but then you have to actually deal with Common Lisp, which is not the kind of lisp that interests me. The more functional-oriented lisps like this Owl, and Clojure, are quite different in many ways from CL.
It's my favorite Scheme. It's minimalist, but practical, and usable for Real Work. It's everything I like about Racket, without all thinks I don't like about Racket (Racket's a fine language, it's just not my thing).
Taking advantage of immutability and using clojure.spec generators at the top level, it specializes/simplifies the code using really simple transformations.
The perf is generally comparable (each has optimizations the other does not, although gambit is a bit faster in the general case), but Chicken has really fast call/cc. Also, Gambit has a very small library collection, especially compared to Chicken's, which is among the best of all the schemes, Library-wise. Neither supports native threading, and Chicken isn't fully re-entrant, which can lead to some problems integrating some libraries. Both have excellent FFI, but Chicken's is a bit better, IMHO.
What's so novel about Chicken's GC? Cheney on the MTA is quite clearly novel (Chicken compiles to CPS and essentially GCs its stack frames IIRC, making call/cc as fast as any other procedure call), but the algorithm itself is quite ordinary, IIRC.
