MouseX::Getopt(3pm)

✨ MouseX::Getopt ✨

okay bestie, welcome to MouseX::Getopt — a Mouse role for processing command line options 💅 she's the manual page, she's the moment, she's giving constructor energy.

---

🌸 SYNOPSIS 🌸

no thoughts, just vibes and this exact code, copy it character for character:

## In your class
package My::App;
use Mouse;

with 'MouseX::Getopt';

has 'out' => (is => 'rw', isa => 'Str', required => 1);
has 'in'  => (is => 'rw', isa => 'Str', required => 1);

# ... rest of the class here

## in your script
#!/usr/bin/perl

use My::App;

my $app = My::App->new_with_options();
# ... rest of the script here

## on the command line
% perl my_app_script.pl -in file.input -out file.dump

like. she really did that. 🎀

---

💖 DESCRIPTION 💖

So basically: this is a role that hands you an alternate constructor for making objects out of the params people typed on the command line. slay.

This module tries to DWIM as much as it possibly can with your command line params by introspecting your class's attributes. She takes your attribute's name and uses it as the command line option, and if there's a type constraint defined, she'll configure Getopt::Long to handle that option accordingly. it's giving mind reader, no cap 🧚

You can use the trait MouseX::Getopt::Meta::Attribute::Trait or the attribute metaclass MouseX::Getopt::Meta::Attribute to get non-default commandline option names and aliases. obsessed.

You can use the trait MouseX::Getopt::Meta::Attribute::Trait::NoGetopt or the attribute metaclass MouseX::Getopt::Meta::Attribute::NoGetopt to have "MouseX::Getopt" straight up ignore your attribute in the commandline options. she said not today 🙈

By default, attributes that start with an underscore do not get commandline argument support — unless the attribute's metaclass is set to MouseX::Getopt::Meta::Attribute. And if you don't want your accessors to have that 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', ...);

What that means: Getopt will not handle a --foo param, but your code can still call the "foo" method. she's private but she's also accessible, main character duality 💅

If your class also uses a configfile-loading role based on MouseX::ConfigFromFile, like MouseX::SimpleConfig, then MouseX::Getopt's "new_with_options" will load the configfile specified by the "--configfile" option for you — or the default you've given for the configfile attribute. she'll handle it, don't worry 🫶

Options specified in multiple places follow this precedence order: commandline overrides configfile, which overrides explicit new_with_options parameters. periodt.

---

✨ Supported Type Constraints ✨

Bool

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

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

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

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

yes queen, both of them 💖

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. cute, typed, correct. ⭐

ArrayRef

An ArrayRef type constraint is set up as a multiple value option in Getopt::Long. So 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 these command line options:

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

stack 'em up bestie, she's collecting 💜

HashRef

A HashRef type constraint is set up as a hash value option in Getopt::Long. So 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 these command line options:

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

key=value girlies rise 🙈

---

🦋 Custom Type Constraints 🦋

ngl, it is possible to create custom type constraint to option spec mappings if you need them. The process is fairly simple (but a little verbose maybe, she's a talker). First you create a custom subtype, like so:

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

Then you register the mapping, like so:

MouseX::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 :) — no literally, they want them, send them 💌

---

🌈 Inferred Type Constraints 🌈

If you define a custom subtype which is a subtype of one of the standard "Supported Type Constraints" above, and you do not explicitly provide custom support like in "Custom Type Constraints" above, then MouseX::Getopt will treat it like the parent type for Getopt purposes.

For example, if you had that same custom "ArrayOfInts" subtype from the examples above, but didn't 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@". she infers, she doesn't stress 💅

---

🎀 new_with_options (%params) 🎀

This method will take a set of default %params and then collect params from the command line (possibly overriding those in %params) and then return a newly constructed object. it's giving builder, it's giving factory, it's giving everything 🔥

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 params 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.

--?
--help
--usage

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

---

🍓 ARGV 🍓

This accessor contains a reference to a copy of the @ARGV array as it originally existed at the time of "new_with_options". she remembers where she came from 🫶

🍓 extra_argv 🍓

This accessor contains an arrayref of leftover @ARGV elements that Getopt::Long did not parse. Note that the real @ARGV is left un-mangled. no touchy. 🙈

🍓 usage 🍓

This accessor contains the Getopt::Long::Descriptive::Usage object (if Getopt::Long::Descriptive is used).

🍓 help_flag 🍓

This accessor contains the boolean state of the --help, --usage and --? options (true if any of these options were passed on the command line).

🍓 meta 🍓

This returns the role meta object. iconic.

---

👑 AUTHORS 👑

look at this roster. absolute legends, every single one:

• NAKAGAWA Masaki <masaki@cpan.org>
• FUJI Goro <gfuji@cpan.org>
• Stevan Little <stevan@iinteractive.com>
• Brandon L. Black <blblack@gmail.com>
• Yuval Kogman <nothingmuch@woobling.org>
• Ryan D Johnson <ryan@innerfence.com>
• Drew Taylor <drew@drewtaylor.com>
• Tomas Doran <bobtfish@bobtfish.net>
• Florian Ragwitz <rafl@debian.org>
• Dagfinn Ilmari Mannsaker <ilmari@ilmari.org>
• Avar Arnfjord Bjarmason <avar@cpan.org>
• Chris Prather <perigrin@cpan.org>
• Mark Gardner <mjgardner@cpan.org>
• Tokuhiro Matsuno <tokuhirom@cpan.org>

---

📜 COPYRIGHT AND LICENSE 📜

This software is copyright (c) 2012 by Infinity Interactive, Inc.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

---

ok so that's the whole page bestie, nothing skipped, nothing fudged, every flag and every =s@ exactly where it belongs 💖

and finally, the lil sign-off at the very bottom: this beauty is documented for perl v5.32.1, dated 2021-09-16, and she lives in the manual as MouseX::Getopt(3pm). slay, go build something. 🦋✨💅