If you feel that a certain library should be written then please add it to Suggested Programming Projects or write it yourself.
A clean and up-to-date, yet rather subjective listing of recommended libraries can be found here
Library management / installation / Handling Packages
- Quicklisp - A popular way of obtaining lisp libraries
- asdf - System definition, aka Makefiles(in some implementation like sbcl, this is already installed by default)
- xelf - Formerly known as blocky. "Xelf extends Common Lisp with an Emacs-inspired 2D OpenGL game engine, a game project editor interface, and an integrated command shell" - http://www.xelf.me
General purpose utility libraries and commonly used libraries
- alexandria - Collection of portable general purpose utilities. Used by a large number of other projects.
- iterate - iterate is a lispy and extensible replacement for the LOOP macro.
- closer-mop - A popular compatibility library allowing portable access to the MOP across implementations.
- Regular expressions: cl-ppcre - highly useful and fast regular expressions engine.
- Pattern Matching: optima - ML-style optimized pattern matcher.
- Salza2 is a Common Lisp library for creating compressed data in the ZLIB, DEFLATE, or GZIP data formats, described in RFC 1950, RFC 1951, and RFC 1952, respectively. It does not use any external libraries for compression. It does not yet support decompression.
- Chipz is a decompression library for decompressing DEFLATE (RFC 1951) data such as ZLIB (RFC 1950), GZIP (RFC 1952), as well as bzip2.
Common data formatsXML:
- CXML namespace, validating, SAX, StAX, W3C DOM, XPath 1.0, XSLT 1.0
- S-XML simple XML parser
- XMLS simple XML parser
- cl-json : A CLOS-extensible JSON parser and generator.
- yason: Another extensible JSON parse and generator.
- CL-CSV : a library to parse and write csv (comma-separated-values) files.
The book Practical Common Lisp implements an id3v2 parser, the source code can be found at PCL:s website
System and low level management
- Threads: Bordeaux-Threads
- Files and directories: UIOP
- OS Interface:
- Foreign language interface:
- Memory management: trivial-garbage includes support for finalization and weak hash tables
- Log4CL is high performance extensible logging library for Common Lisp
- LIFT is a testing framework
- FiveAM is a simple regression testing framework
- Stefil is a test framework, and its philosophy is to stay as transparent as possible
- CLUnit is unit testing framework designed to be easy to use
Graphics librariesGraphical User Interface:
Graphical drawing library:
- vecto < cl-vectors < zpng : writing vector graphics on PNG format.
- cl-cairo2 : cairo binding for Common Lisp.
- clinch : 3d-graphics engine built on-top of OpenGL
- lispbuilder-sdl : Lispbuilder-SDL provides Common Lisp bindings for the SDL graphics library.
- mixalot. Mixalot currently consists of a mixer component providing straightforward audio output on Linux (via ALSA) and other platforms (using libao), a CFFI binding to the libmpg123 library, and a helper component allowing playback of MP3 files through the mixer.
Web developmentHTTP server and frameworks:
- Hunchentoot the de-facto standard HTTP web server
- CL-Weblocks a continuations based framework
- Clack a web application environment for Common Lisp inspired by Python's WSGI and Ruby's Rack
- ningle a very lightweight web application framework
- Wookie an async application/web server
- Drakma - an HTTP/HTTPS client library with session management and more.
- CL-WHO HTML generator
- css-lite is a library for generating CSS from an s-exp based syntax
- quri URI library
- CL-DBI Database independent interface for Common Lisp
- postmodern: designed for PostgreSQL
- hu.dwim.rdbms: nicer API than CLSQL; but not as many backends yet
- hu.dwim.perec: the ORM of choice (if you're into ORMs at all...); based on hu.dwim.rdbms
- Character encoding/decoding: flexi-streams - focus on features
- Character encoding/decoding: babel - focus on speed
- Character categories, etc: cl-unicode
- Localization (number formats, etc): cl-l10n
APIs to websites
- Ironclad : A native Common Lisp package with support for several ciphers and hash functions
Parallel, concurrent and async programming
- lparallel : A Common Lisp library for parallel programming
- chanl : ChanL is a concurrency library built on top of bordeaux-threads that provides channels as thread-synchronisation primitives
- cl-async : cl-async implements a higher-level interface for non-blocking, asynchronous programming in Common Lisp