A series is a data structure much like a sequence, with similar kinds of operations. The difference is that in many situations, operations on series may be composed functionally and yet execute iteratively, without the need to construct intermediate series values explicitly. In this manner, series provide both the clarity of a functional programming style and the efficiency of an iterative programming style. Series is the culmination of many years of design and use of this approach, during which some 100,000 lines of application code have been written (by about half a dozen people over the course of seven years) using the series facility in nearly all iteration situations. This includes one large system (KBEmacs) of over 40,000 lines of code. In a nutshell: Think "Efficient MAPCAR". SERIES translates functional-style expressions into efficient loops.
CL-BibTeX is a replacement for the BibTeX program, written in Common Lisp. The aim is to enable the user to format bibliographic entries using Common Lisp programs, rather than using the stack language of BibTeX style files. A compiler that transforms BibTeX style files into comprehensible Common Lisp programs is included.
Charlemagne is a versatile genetic programming application. It includes a commandline client and an interactive console mode. It is written in Python and Lisp, and is user extensible to some degree in both languages. It features built-in input-output mapping support and provides the ability to define complex fitness calculations in Lisp or Python.
ACL2 is a mathematical logic, programming language, and mechanical theorem prover based on the applicative subset of Common Lisp. It is an "industrial-strength" version of the NQTHM or Boyer/Moore theorem prover, and has been used for the formal verification of commercial microprocessors, the Java Virtual Machine, interesting algorithms, and so forth.