1 Introduction

The Genparse package allows the automated creation of command line parsing routines, based on a command line option description file. Given a target language, Genparse outputs a suitable parser. For example, in C, a function is created that reads the command line parameters and stores their values in a data structure. In C++ and Java, a command line parsing class is created, with member functions that return parameter values.

The goal of Genparse is to eliminate the effort required to write a command line parser for every newly-developed program. Typically, these parsers all follow a very similar format, with a series of calls to the getopt () or getopt_long () library functions. Genparse allows users to specify their program’s command line options in a concise text file (hereafter, a "Genparse File"). Genparse reads this file, and produces the appropriate parsing routines in the user’s language of choice. Users may call the parser’s functions from their main code in order to obtain the values of the parameters.

In addition to providing a simple interface to the parameters, Genparse also has the following features:

• A default value may be provided for each parameter.
• Both short (-o) and long (--option) parameters are supported.
• For parameters that take numerical values, Genparse can make sure that the input values fall within a given range.
• A usage () function is automatically created, which can be used to describe a program’s command line parameters. Genparse also allows a description string to be associated with each parameter. These strings will be displayed in the usage () function.
• For C and C++ extra include files may be added to any command line parser.
• Each parameter can have a callback function associated with it. Genparse will automatically create a skeleton for callback functions, which the user can fill in. Also, global callback functions can be specified.
• The generated parser is 100% GNU compatible because the parsing itself is done by the GNU getopt_long function.
• The generated code is internationalizable (See internationalize.).

Currently, we do not believe that Genparse has any significant limitations. It cannot handle dependencies between different options, but the user can write callback function to accomplish this task. A virtually unlimited number of long command line options are available, but only 52 single-character options can be used by a given program.

Mail suggestions and bug reports for Genparse to mike@borella.net. The latest version of Genparse can always be found at http://genparse.sourceforge.net.