Skippy is a Common Lisp library to read and write GIF image files.

This package provides a PNG Common Lisp system to operate with Portable Network Graphics file format.

CLOBBER is an alternative to so-called object prevalence, and in particular to cl-prevalence. Clobber is both simpler, more flexible, and more robust than systems based on object prevalence.

This library builds on the venerable idea of dynamically memoizing functions. A memoized function remembers results from previous computations and returns cached results when called again with the same arguments rather than repeating the computation.

This package provides a Common Lisp system which wraps the BORDEAUX-THREADS system to be able to run things in the main thread of the implementation, for example drawing calls of GUI applications.

Command-Line-Args provides a main macro (command) that wraps a defun form and creates a new function that parses the command line arguments. It has support for command-line options, positional, and variadic arguments. It also generates a basic help message. The interface is meant to be easy and non-intrusive.

The GNU Scientific Library for Lisp (GSLL) allows the use of the GNU Scientific Library (GSL) from Common Lisp. This library provides a full range of common mathematical operations useful to scientific and engineering applications. The design of the GSLL interface is such that access to most of the GSL library is possible in a Lisp-natural way; the intent is that the user not be hampered by the restrictions of the C language in which GSL has been written. GSLL thus provides interactive use of GSL for getting quick answers, even for someone not intending to program in Lisp.

POLICY-COND provides tools to insert and execute code based on a compiler's OPTIMIZE policy. It also contains a contract-like notion of expectations, which allow dynamic checking or inclusion of various things that should happen depending on compiler policy.

This library is a collection of functions and macros for manipulating Common Lisp arrays and performing numerical calculations with them.

This system is an implementation of the Common Lisp type system; particularly cl:typep and cl:subtypep.

This package provides support routines for the claw Common Lisp package.

This package provides a Common Lisp library for defining OpenGL shader programs. There are also functions for referencing shader programs by name, querying for basic information about them, modifying uniform variables throughout the lifecycle of an OpenGL application, and managing certain OpenGL buffer object types (UBO, SSBO currently).

On Cliki.net <http://www.cliki.net/Common%20Lisp%20Utilities>, there is a collection of Common Lisp Utilities, things that everybody writes since they're not part of the official standard. There are some very useful things there; the only problems are that they aren't implemented as well as you'd like (some aren't implemented at all) and they aren't conveniently packaged and maintained. It takes quite a bit of work to carefully implement utilities for common use, commented and documented, with error checking placed everywhere some dumb user might make a mistake.

This package implements binary trees of various kinds, presenting a uniform interface to them all.

Common Lisp implementation of UUIDs according to RFC4122.

This package provides an embedded template engine for Common Lisp.

CL-Ledger is a Common Lisp port of the Ledger double-entry accounting system.

CMN provides a package of functions to hierarchically describe a musical score. When evaluated, the musical score is rendered to an image.

The GRAPH Common Lisp library provides a data structures to represent graphs, as well as some graph manipulation and analysis algorithms (shortest path, maximum flow, minimum spanning tree, etc.).

LTK is a Common Lisp binding for the Tk graphics toolkit. It is written in pure Common Lisp and does not require any Tk knowledge for its usage.

CIEL is a ready-to-use collection of libraries providing: a binary, to run CIEL scripts; a simple full-featured REPL for the terminal; a Lisp library and a core image.

FXML is a secure-by-default, error-recovering XML parser and serializer. It is a fork of CXML.

You should use FXML instead of CXML if:

• You are parsing potentially ill-formed XML.

• You are parsing potentially malicious XML.

• You need to use Klacks with namespaces.

FXML’s API is very close to CXML's, and for the most part you can refer to the CXML documentation for usage.

Linedit is a readline-style library written in Common Lisp that provides customizable line-editing for Common Lisp programs.

trivial-download allows you to download files from the Internet from Common Lisp. It provides a progress bar.