Reliable, high performance Scheme compiler

 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 Revised^6 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.