SLY is a fork of SLIME, an IDE backend for Common Lisp. It also features a completely redesigned REPL based on Emacs's own full-featured comint-mode, live code annotations, and a consistent interactive button interface. Everything can be copied to the REPL. One can create multiple inspectors with independent history.

FSet is a functional set-theoretic collections library for Common Lisp. Functional means that all update operations return a new collection rather than modifying an existing one in place. Set-theoretic means that collections may be nested arbitrarily with no additional programmer effort; for instance, sets may contain sets, maps may be keyed by sets, etc.

CL-UNICODE is a portable Unicode library Common Lisp, which is compatible with perl. It is pretty fast, thread-safe, and compatible with ANSI-compliant Common Lisp implementations.

This package provides Common Lisp FFI bindings for libwayland, primarily for the mahogany window manager.

Max’s Parser Combinators is a simple and pragmatic library for writing parsers and lexers based on combinatory parsing. MaxPC is capable of parsing deterministic, context-free languages, provides powerful tools for parse tree transformation and error handling, and can operate on sequences and streams. It supports unlimited backtracking, but does not implement Packrat Parsing. Instead, MaxPC achieves good performance through its optimized primitives, and explicit separation of matching and capturing input. In practice, MaxPC parsers perform better on typical computer languages—when compared to Packrat parsers—at the expense of not producing linear-time parsers.

Common Lisp comes with quite some functions to compare objects for equality, yet none is applicable in every situation and in general this is hard, as equality of objects depends on the semantics of operations on them. As consequence, users find themselves regularly in a situation where they have to roll their own specialized equality test.

This module provides one of many possible equivalence relations between standard Common Lisp objects. However, it can be extended for new objects through a simple CLOS protocol. The rules when two objects are considered equivalent distinguish between mutating and frozen objects. A frozen object is promised not to be mutated in the future in a way that operations on it can notice the difference.

We have chosen to compare mutating objects only for identity (pointer equality), to avoid various problems. Equivalence for frozen objects on the other hand is established by recursing on the objects' constituent parts and checking their equivalence. Hence, two objects are equivalent under the OBJECT= relation, if they are either identical, or if they are frozen and structurally equivalent, i.e. their constituents are point-wise equivalent.

Since many objects are potentially mutable, but are not necessarily mutated from a certain point in their life time on, it is possible to promise to the equivalence relation that they remain frozen for the rest of their life time, thus enabling coarser equivalence than the often too fine-grained pointer equality.

The Common Foreign Function Interface (CFFI) purports to be a portable foreign function interface for Common Lisp. The CFFI library is composed of a Lisp-implementation-specific backend in the CFFI-SYS package, and a portable frontend in the CFFI package.

Hypergeometrica is a Common Lisp library for performing high-precision arithmetic, with a focus on performance. At the heart of it all are routines for multiplication. Hypergeometrica aims to support:

• In-core multiplication using various algorithms, from schoolbook to floating-point FFTs.

• In-core multiplication for large numbers using exact convolutions via number-theoretic transforms, which is enabled by 64-bit modular arithmetic.

• Out-of-core multiplication using derivatives of the original Cooley–Tukey algorithm.

On top of multiplication, one can build checkpointed algorithms for computing various classical constants, like \pi.

Dissect is a small Common Lisp library for introspecting the call stack and active restarts.

This package provides a Common Lisp system CHLOROPHYLL which implements an ANSI escape code functionality.

cl-inotify uses cl-cffi to provide a Common Lisp interface to the Linux inotify API.

This package provides CFFI bindings to the Graphviz library in Common Lisp.

Alexandria is a collection of portable utilities. It does not contain conceptual extensions to Common Lisp. It is conservative in scope, and portable between implementations.

Common Lisp port of Universal Tween Engine.

These common lisp sources contain two variants of the Nelder-Mead algorithm. The original algorithm and a provably convergent, reliable variant by A. Bürmen et al, called the GRNMA.

This package provides functions to encode or decode byte vectors or byte streams using the Z85 format, which is a base-85 encoding used by ZeroMQ.

DATA-SIFT is a Common Lisp data validation and transformation library inspired by cl-data-format-validation and WTForms validators.

Common Lisp implementation of Graham Cormode and S. Muthukrishnan's Effective Computation of Biased Quantiles over Data Streams in ICDE’05.

This is a lightweight, non-consing, optimized queue implementation for Common Lisp.

Opticl is a Common Lisp library for representing, processing, loading, and saving 2-dimensional pixel-based images.

This is a simple extension to MODULARIZE that allows modules to define and trigger hooks, which other modules can hook on to.

Spatial-trees is a set of dynamic index data structures for spatially-extended data.

It's very basic implementation of channels and queue for Common Lisp.

IOlib is to be a better and more modern I/O library than the standard Common Lisp library. It contains a socket library, a DNS resolver, an I/O multiplexer(which supports select(2), epoll(4) and kqueue(2)), a pathname library and file-system utilities.