Chez Scheme is both a programming language and an implementation of that
language, with supporting tools and documentation.

As a superset of the language described in the Revised6 Report on the
Algorithmic Language Scheme (R6RS), Chez Scheme supports all standard
features of Scheme, including first-class procedures, proper treatment of
tail calls, continuations, user-defined records, libraries, exceptions, and
hygienic macro expansion.

Chez Scheme also includes extensive support for interfacing with C and
other languages, support for multiple threads possibly running on multiple
cores, non-blocking I/O, and many other features.

The Chez Scheme implementation consists of a compiler, run-time system, and
programming environment. Although an interpreter is available, all code is
compiled by default. Source code is compiled on-the-fly when loaded from a
source file or entered via the shell. A source file can also be precompiled
into a stored binary form and automatically recompiled when its
dependencies change. Whether compiling on the fly or precompiling, the
compiler produces optimized machine code, with some optimization across
separately compiled library boundaries. The compiler can also be directed
to perform whole-program compilation, which does full cross-library
optimization and also reduces a program and the libraries upon which it
depends to a single binary.