"new_with_options (%params)"

The special parameter "argv", if specified should point to an array reference with an array to use instead of @ARGV.

If "GetOptions" in Getopt::Long fails (due to invalid arguments), "new_with_options" will throw an exception.

If Getopt::Long::Descriptive is installed and any of the following command line parameters are passed, the program will exit with usage information (and the option's state will be stored in the help_flag attribute). You can add descriptions for each option by including a documentation option for each attribute to document.

  -?
  --?
  -h
  --help
  --usage

If you have Getopt::Long::Descriptive the "usage" parameter is also passed to "new" as the usage option.

"ARGV"

"extra_argv"

Important: By default, Getopt::Long will reject unrecognized options (that is, options that do not correspond with attributes using the "Getopt" trait). To disable this, and allow options to also be saved in "extra_argv" (for example to pass along to another class's "new_with_options"), you can either enable the "pass_through" option of Getopt::Long for your class: "use Getopt::Long qw(:config pass_through);" or specify a value for MooseX::Getopt::GLD's "getopt_conf" parameter.

"usage"

"help_flag"

"print_usage_text"

"meta"

"process_argv (%params)"

This module attempts to DWIM as much as possible with the command line parameters by introspecting your class's attributes. It will use the name of your attribute as the command line option, and if there is a type constraint defined, it will configure Getopt::Long to handle the option accordingly.

You can use the trait MooseX::Getopt::Meta::Attribute::Trait or the attribute metaclass MooseX::Getopt::Meta::Attribute to get non-default command-line option names and aliases.

You can use the trait MooseX::Getopt::Meta::Attribute::Trait::NoGetopt or the attribute metaclass MooseX::Getopt::Meta::Attribute::NoGetopt to have "MooseX::Getopt" ignore your attribute in the command-line options.

By default, attributes which start with an underscore are not given command-line argument support, unless the attribute's metaclass is set to MooseX::Getopt::Meta::Attribute. If you don't want your accessors to have the leading underscore in their name, you can do this:

  # for read/write attributes
  has '_foo' => (accessor => 'foo', ...);

  # or for read-only attributes
  has '_bar' => (reader => 'bar', ...);

This will mean that MooseX::Getopt will not handle a --foo parameter, but your code can still call the "foo" method.

If your class also uses a configfile-loading role based on MooseX::ConfigFromFile, such as MooseX::SimpleConfig, MooseX::Getopt's "new_with_options" will load the configfile specified by the "--configfile" option (or the default you've given for the configfile attribute) for you.

Options specified in multiple places follow the following precedence order: command-line overrides configfile, which overrides explicit new_with_options parameters.

Supported Type Constraints

Bool

A Bool type constraint is set up as a boolean option with Getopt::Long. So that this attribute description:

  has 'verbose' => (is => 'rw', isa => 'Bool');
    

would translate into "verbose!" as a Getopt::Long option descriptor, which would enable the following command line options:

  % my_script.pl --verbose
  % my_script.pl --noverbose
    

Int, Float, Str

These type constraints are set up as properly typed options with Getopt::Long, using the "=i", "=f" and "=s" modifiers as appropriate.

ArrayRef

An ArrayRef type constraint is set up as a multiple value option in Getopt::Long. So that this attribute description:

  has 'include' => (
      is      => 'rw',
      isa     => 'ArrayRef',
      default => sub { [] }
  );
    

would translate into "includes=s@" as a Getopt::Long option descriptor, which would enable the following command line options:

  % my_script.pl --include /usr/lib --include /usr/local/lib
    

HashRef

A HashRef type constraint is set up as a hash value option in Getopt::Long. So that this attribute description:

  has 'define' => (
      is      => 'rw',
      isa     => 'HashRef',
      default => sub { {} }
  );
    

would translate into "define=s%" as a Getopt::Long option descriptor, which would enable the following command line options:

  % my_script.pl --define os=linux --define vendor=debian
    

Custom Type Constraints

  subtype 'ArrayOfInts'
      => as 'ArrayRef'
      => where { scalar (grep { looks_like_number($_) } @$_)  };

Then you register the mapping, like so:

  MooseX::Getopt::OptionTypeMap->add_option_type_to_map(
      'ArrayOfInts' => '=i@'
  );

Now any attribute declarations using this type constraint will get the custom option spec. So that, this:

  has 'nums' => (
      is      => 'ro',
      isa     => 'ArrayOfInts',
      default => sub { [0] }
  );

Will translate to the following on the command line:

  % my_script.pl --nums 5 --nums 88 --nums 199

This example is fairly trivial, but more complex validations are easily possible with a little creativity. The trick is balancing the type constraint validations with the Getopt::Long validations.

Better examples are certainly welcome :)

Inferred Type Constraints

For example, if you had the same custom "ArrayOfInts" subtype from the examples above, but did not add a new custom option type for it to the "OptionTypeMap", it would be treated just like a normal "ArrayRef" type for Getopt purposes (that is, "=s@").

More Customization Options

Note in particular that the default setting for case sensitivity has changed over time in Getopt::Long::Descriptive, so if you rely on a particular setting, you should set it explicitly, or enforce the version of Getopt::Long::Descriptive that you install.