Here's a list of the R6RS Schemes that I know about:
So that's eight that are currently out there. With Guile, it may soon
be nine. And the Gambit/R6RS project looks promising too.
Question... are there any others out there?
So far, we're heavy on the native code compilers (Chez, Larceny,
Ikarus). No Scheme-to-C based systems have shown up. It's big in Japan
(Ypsilon, Mosh, Biwa). I'm looking forward to a JVM based
implementation; Leppie is taking care of .Net (IronScheme).
Unfortunately, it is my understanding that this is abandonware.
> Unfortunately, it is my understanding that this is abandonware.
It's been updated throughout 2010 and last updated about a week ago.
See the darcs repository for details.
> It's big in Japan (Ypsilon, Mosh, Biwa).
I wouldn't praise Biwa that much, as far as I have seen they plan for
R6RS, but they don't even have syntax-rules. I wouldn't consider
it a practically usable implementation just yet.
Petit Larceny is a Scheme-to-C system. See http://www.larcenists.org/