Steel Bank Common Lisp
Steel Bank Common Lisp is a development
environment for Common Lisp, with excellent
support for the ANSI standard: garbage collection,
lexical closures, powerful macros, strong dynamic
typing, incremental compilation, and the famous
Common Lisp Object System (multimethods and all).
It also includes many extensions, such as native
threads, socket support, a statistical profiler,
programmable streams, and more. These are all
available through an integrated, interactive
native compiler which feels like an interpreter.
SBCL is unique in being a multiplatform native
compiler which bootstraps itself completely from
source, using a C compiler and any other ANSI
Common Lisp implementation.