Getopt::Declare Declaratively Expressed Command-Line Arguments via Regular Expressions

Getopt::Declare is yet another command-line argument parser, one which is specifically designed to be powerful but exceptionally easy to use.

To parse the command-line in `@ARGV', one simply creates a Getopt::Declare object, by passing `Getopt::Declare::new()' a specification of the various parameters that may be encountered:

$args = new Getopt::Declare($specification);

The specification is a single string such as this:

$specification = q(

-a Process all data

            -b <N:n>        Set mean byte length threshold to <N>
                                    { bytelen = $N; }

            +c <FILE>       Create new file <FILE>

            --del           Delete old file
                                    { delold() }

            delete          [ditto]

            e <H:i>x<W:i>   Expand image to height <H> and width <W>
                                    { expand($H,$W); }

            -F <file>...    Process named file(s)
                                    { defer {for (@file) {process()}} }

            =getrand [<N>]  Get a random number
                            (or, optionally, <N> of them)
                                    { $N = 1 unless defined $N; }

            --              Traditionally indicates end of arguments
                                    { finish }

);

in which the syntax of each parameter is declared, along with a description and (optionally) one or more actions to be performed when the parameter is encountered. The specification string may also include other usage formatting information (such as group headings or separators) as well as standard Perl comments (which are ignored).

Calling Getopt::Delare::new() parses the contents of the array @ARGV, extracting any arguments which match the parameters defined in the specification string, and storing the parsed values as hash elements within the new Getopt::Declare object being created.

Other features of the Getopt::Declare package include:

• The use of full Perl regular expressions to constrain matching of parameter components.
• Automatic generation of error, usage and version information.
• Optional conditional execution of embedded actions (i.e. only on successful parsing of the entire command-line)
• Strict or non-strict parsing (unrecognized command-line elements may either trigger an error or may simply be left in @ARGV)
• Declarative specification of various inter-parameter relationships (for example, two parameters may be declared mutually exclusive and this relationship will then be automatically enforced).
• Intelligent clustering of adjacent flags (for example: the command-line sequence "-a -b -c" may be abbreviated to "-abc", unless there is also a `-abc' flag declared).
• Selective or global case-insensitivity of parameters.
• The ability to parse files (especially configuration files) instead of the command-line.

CHANGES

See the file 'Changes' for a list of changes and release dates.

INSTALLATION

Note: requires the Text::Balanced module

Getopt::Declare has been uploaded to the CPAN:

http://search.cpan.org/search?query=getopt+declare

So, the easiest way is to use the 'cpan' command if it is installed on your computer:

cpan Getopt::Declare

Otherwise

perl Makefile.PL make make test make install

Consult the POD for exhaustive documentation:

perldoc Getopt::Declare

Also, some demos are available in the demos folder.

AUTHOR

Damian Conway <damian@conway.org>

COPYRIGHT

       Copyright (c) 1997-2000, Damian Conway. All Rights Reserved.
     This module is free software. It may be used, redistributed
     and/or modified under the terms of the Perl Artistic License
          (see http://www.perl.com/perl/misc/Artistic.html)

BUGS AND ANNOYANCES

There are undoubtedly serious bugs lurking somewhere in this code.

If nothing else, it shouldn't take 1500 lines to explain a package that was designed for intuitive ease of use!

Bug reports and other feedback are most welcome at:

https://rt.cpan.org/Public/Bug/Report.html?Queue=Getopt-Declare