There are three packages by the name of CLON, although the third one doesn't actually introduce any conflict because the package is named net.didierverna.clon.

Clon: A cron-like scheduling library

A task scheduler library much like cron for lisp that is implemented as a shallow layer on top of SBCL timers. It's written by Gabor Melis and can be found at It's forked near 2014 with some bug-fix.

It's then forked again by Jin-Cheng Guu in mid 2021 into his repo, aiming to let clon replace traditional cron managers. (It's renamed to cl-schedule since v0.0.5 as there are too many name clashes.) The forked version also provides more examples, documents and features. In particular, in an example below we show how to make a schedule that does what a traditional cron manager would do for the control string

*/25 5-6,10 * 7 1-2

Long story short, it can be expressed as the following.


:minute '(satisfies twenty-five-p)

:hour '(or (integer 5 6) (member 10))

:month 7

:day-of-week '(integer 0 1))

Clon: Common Lisp Object Network

CLON (Common Lisp Object Network) is a prototype-based object system for Common Lisp written by David O'Toole. The details of inheritance, message passing, and field lookup are inspired by the Io language and the Garnet UI toolkit (KR in particular). It doesn't seem to be available anywhere. CLON is used in RLX, a game engine for rogue-like games.

Clon: the Command-Line Options Nuker

Clon is a library for managing command-line options in standalone Common Lisp applications. It provides a unified option syntax with both short and long names, automatic completion of partial names and automatic retrieval/conversion of option arguments from the command-line, associated environment variables, fallback or default values. Clon comes with a set of extensible option types (switches, paths, strings etc.). Clon also provides automatic generation and formatting of help strings, with support for highlighting on tty's through ISO/IEC 6429 SGR. This formatting is customizable through "themes".

Clon currently works on Unix (including MacOS X) and Windows (Cygwin, MinGW/MSYS) with SBCL, CMUCL, CCL, ECL, CLISP, ABCL, Allegro (both standard and modern) and LispWorks.

Clon is written by Didier Verna. Clon's homepage is here.

command-line options parser