Scheme48

Scheme 48 is a free software Scheme implementation using a bytecode interpreter. It has a foreign function interface for calling functions from C and comes with a regex library, and a POSIX interface. It is supported by SLIB, the portable Scheme library and is the basis for Scsh, the Scheme shell. It has been used in academic research

It is called "Scheme 48" because the first version was written in 48 hours in August 1986.

The authors now say it is intended to be understood in 48 hours.

Scheme 48 uses a Virtual Machine to interpret the bytecode, which is written in a restricted dialect of Scheme called PreScheme, which can be translated to C and compiled to a native binary.