"Schlep Toolchains" <
http://people.csail.mit.edu/jaffer/Schlep>
documents and distributes the hyper-cross-platform technology used to
create the WB B-tree database libraries for C, C#, and Java from source
written in a subset of R4RS.
Schlep Toolchains and WB are also used for the new implementation of
Water <http://waterlanguage.org/>.