another Scheme implementation, though, there's no compelling reason to switch.
Another good Scheme implementation is Chicken. For our purposes, this is in some
-respects superior to Racket, and in other respects inferior.
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+respects superior to Racket, and in other respects inferior. <!--
Racket doesn't have R7RS-small, and won't anytime soon. :-(
Also Chicken's library collection seems stronger, or at least better organized and maintained.
Other R7RS-friendly: [Gauche](http://practical-scheme.net/gauche), [Chibi](https://code.google.com/p/chibi-scheme).