Exiguous command-line option parser.

Fanion is a Common Lisp library for parsing command-line options. It parses them in the same way as OpenBSD getopt(3), but additionally supports long options, though currently with limitations (see Current issues).

This library is intentionally spartan in its functionality. It can parse options and nothing else; it cannot parse non-option arguments or subcommands, and it does not automatically generate usage of help messages. However, Fanion's option parsing should be flexible enough to cater to many use-cases thanks to its option-value reduction, which is modeled after Adopt's. See the manual for more information.

Fanion is currently under active development and its API is unstable, but it follows Semantic Versioning so breaking changes will be indicated by an appropriate bump in version number.

Fanion is not available on Quicklisp, so you will need to clone it to a location known to ASDF or Quicklisp:

git clone https://git.sr.ht/~paulapatience/fanion

Fanion has no dependencies beyond ASDF/UIOP. It is developed on SBCL, but should be compatible with any conventional Common Lisp implementation.

The Common Lisp files located in Fanion's scripts directory are good examples of Fanion being used in practice. The following is an extract of scripts/build-documentation.lisp:

(defparameter +options+
  (list
   (fanion:make-option 'format #\f nil
                       :value #'parse-format)
   (fanion:make-option 'help nil "help")
   (fanion:make-option 'output #\o nil
                       :value #'parse-output
                       :initial-value uiop:*stdout*)))

(fanion:parse +options+ (uiop:command-line-arguments))

See the documentation of FANION:MAKE-OPTION for further examples of its capabilities.

Fanion is documented in its manual, which consists of an embellished version of this README supplemented with the API reference. It is available in Markdown form and in PDF form, the latter of which is distributed only alongside the release archive.

The manual is regenerated only at each release, so in order to consult the latest available version, you will need to build it manually:

make markdown pdf

Building the manual requires MGL-PAX and Pathname-Utils, and building the PDF manual further requires Pandoc, LuaLaTeX and suitable LaTeX packages.

Long options are supported, but only as booleans. This will be corrected.

Also, no dedicated FANION-ERROR class exists for such errors as unrecognized options and missing values. An error class hierarchy may be added in the future.

More fully featured alternatives to Fanion include:

• Adopt with optional Adopt Subcommands
• clingon
• Clon

The manual contains a more exhaustive list of similar libraries.

Fanion's option-value reduction, consisting of the VALUE, REDUCE and FINALLY arguments to FANION:MAKE-OPTION, is modeled after Adopt's, though in Adopt VALUE is named KEY and REDUCE is required.

This project is licensed under the MIT license (Expat).

Unless you explicitly state otherwise, any contribution intentionally submitted by you for inclusion in this project shall be licensed as above, without any additional terms or conditions.