Lisp GFlags is a Common Lisp implementation of gflags, Google's command line flag parsing library. The library implements functionality similar to that of Google's C++ and Python gflags libraries, which live here:

The code allows you to define command line flags using the DEFINE-FLAG macro. For instance, the following form defines a boolean flag called *DEBUG-FLAG* that is set based on the presence of "--debug" in the application's command line.

(define-flag *debug-flag* :default-value nil :selector "debug" :type boolean :help "Turn on debugging mode?" :documentation "Is debugging mode turned on?")

If the command line contains "--debug" or "--debug=true", then *DEBUG-FLAG* is set to T. Otherwise, it defaults to NIL.

The function PARSE-COMMAND-LINE is used to parse the command line.

The file flag-test.lisp contains more examples.

command-line options parser