A lisp interpreter by Bill Birch of bull, UK, with shallow-binding and dynamic scope. Use of reference counting makes it suitable for experimenting with real-time and graphical user interfaces. common lisp compatibility macros are provided, and most of the examples in "Lisp" by Winston & Horn have been run on RefLisp. RefLisp makes no distinction between symbol-values and function-values, so a symbol can be either but not both. There are Lisp modules for lexical scope and for running indefinite extent scheme programs.

Version 2.67 ("Last Update for a While", the author is emigrating to Australia) includes an interpreter, documentation, examples and a profiler. It runs under ms-dos (cga/ega/vga) and aix.