This is an index to pages that describe various detailed differences between Scheme implementations.
As of 2013-06-08, the list of Scheme implementations tested is:
Racket, Gauche, MIT, Gambit, plain Chicken, Chicken with the numbers egg, Bigloo, Scheme48, scsh, Guile, Kawa, SISC, Chibi, SCM, Chez, Vicare, Larceny, Ypsilon, Mosh, IronScheme, NexJ, JScheme, STklos, KSi, SigScheme, Shoe, TinyScheme, Scheme 9, Dream (link dead), RScheme, S7, BDC, XLisp, Rep, Schemik, Elk, UMB, Oaklisp, Llava, SXM, Sizzle, FemtoLisp, Dfsch, Inlab, Owl Lisp.
My test system runs 32-bit Linux. All Schemes (except JVM-based and CLR-based ones) are built from source, usually the latest release but in some cases the head of source control. However, not all versions are up to date, and the versions tested have changed over the past few years, so some of the claims in the pages below are surely obsolete. Implementers and users are urged to [mailto:email@example.com notify me] when they see something incorrect.
As of 2013-01-31, I was no longer able to build VX or Spark, so they are excluded from the suite from now on. KSM, Luna, MScheme, Schell, QScheme, Rhizome/pi, SIOD, and VSCM either will not build on my system or will not run. For these and many other Schemes see the fairly complete list of Scheme implementations.
S7 was formerly, but incorrectly, known in these pages as "Scheme 7", and some references to this name survive. It's really named after the motorcycle.
Not all these pages have information on all these Schemes.