NAME

Getopt::Class - Extended dictionary version of Getopt::Long

SYNOPSIS

use Getopt::Class;
our $DEBUG = 0;
our $VERBOSE = 0;
our $VERSION = '0.1';
my $dict =
{
    create_user     => { type => 'boolean', alias => [qw(create_person create_customer)], action => 1 },
    create_product  => { type => 'boolean', action => 1 },
    debug           => { type => 'integer', default => \$DEBUG },
    # Can be enabled with --enable-recurse
    disable_recurse => { type => 'boolean', default => 1 },
    # Can be disabled also with --disable-logging
    enable_logging  => { type => 'boolean', default => 0 },
    help            => { type => 'code', code => sub{ pod2usage(1); }, alias => '?', action => 1 },
    man             => { type => 'code', code => sub{ pod2usage( -exitstatus => 0, -verbose => 2 ); }, action => 1 },
    quiet           => { type => 'boolean', default => 0, alias => 'silent' },
    verbose         => { type => 'boolean', default => \$VERBOSE, alias => 'v' },
    version         => { type => 'code', code => sub{ printf( "v%.2f\n", $VERSION ); }, action => 1 },

    api_server      => { type => 'string', default => 'api.example.com' },
    api_version     => { type => 'string', default => 1 },
    as_admin        => { type => 'boolean' },
    dry_run         => { type => 'boolean', default => 0 },
    
    # Can be enabled also with --with-zlib
    without_zlib    => { type => 'integer', default => 1 },

    name            => { type => 'string', class => [qw( person product )] },
    created         => { type => 'datetime', class => [qw( person product )] },
    define          => { type => 'string-hash', default => {} },
    langs           => { type => 'array', class => [qw( person product )], re => qr/^[a-z]{2}([_|-][A-Z]{2})?/, min => 1, default => [qw(en)] },
    currency        => { type => 'string', class => [qw(product)], name => 'currency', re => qr/^[a-z]{3}$/, error => "must be a three-letter iso 4217 value" },
    age             => { type => 'integer', class => [qw(person)], name => 'age', },
    path            => { type => 'file' },
    skip            => { type => 'file-array' },
};

# Assuming command line arguments like:
prog.pl --create-user --name Bob --langs fr ja --age 30 --created now --debug 3 \
        --path ./here/some/where --skip ./bad/directory ./not/here ./avoid/me/

my $opt = Getopt::Class->new({
    dictionary => $dict,
}) || die( Getopt::Class->error, "\n" );
my $opts = $opt->exec || die( $opt->error, "\n" );
$opt->required( [qw( name langs )] );
my $err = $opt->check_class_data( 'person' );
printf( "User is %s and is %d years old\n", $opts{qw( name age )} ) if( $opts->{debug} );

# Get all the properties for class person
my $props = $opt->class_properties( 'person' );

# Get values collected for class 'person'
if( $opts->{create_user} )
{
    my $values = $opt->get_class_values( 'person' );
    # Having collected the values for our class of properties, and making sure all 
    # required are here, we can add them to database or make api calls, etc
}
elsif( $opts->{create_product} )
{
    # etc...
}

# Or you can also access those values as object methods
if( $opts->create_product )
{
    $opts->langs->push( 'en_GB' ) if( !$opts->langs->length );
    printf( "Created on %s\n", $opts->created->iso8601 );
}

VERSION

v0.104.0

DESCRIPTION

Getopt::Class is a lightweight wrapper around Getopt::Long that implements the idea of class of properties and makes it easier and powerful to set up Getopt::Long. This module is particularly useful if you want to provide several sets of options for different features or functions of your program. For example, you may have a part of your program that deals with user while another deals with product. Each of them needs their own properties to be provided.

CONSTRUCTOR

new

To instantiate a new Getopt::Class object, pass an hash reference of following parameters:

dictionary

This is required. It must contain a key value pair where the value is an anonymous hash reference that can contain the following parameters:
- alias
  
  This is an array reference of alternative options that can be used in an interchangeable way
```
my $dict =
{
last_name => { type => 'string', alias => [qw( family_name surname )] },
};
# would make it possible to use either of the following combinations
--last-name Doe
# or
--surname Doe
# or
--family-name Doe
```
- default
  
  This contains the default value. For a string, this could be anything, and also a reference to a scalar, such as:
```
our $DEBUG = 0;
my $dict =
{
debug => { type => 'integer', default => \$DEBUG },
};
```
  It can also be used to provide default value for an array, such as:
```
my $dict =
{
langs => { type => 'array', class => [qw( person product )], re => qr/^[a-z]{2}([_|-][A-Z]{2})?/, min => 1, default => [qw(en)] },
};
```
  But beware that if you provide a value, it will not superseed the existing default value, but add it on top of it, so
```
--langs en fr ja
```
  would not produce an array with en, fr and ja entries, but an array such as:
```
['en', 'en', 'fr', 'ja' ]
```
  because the initial default value is not replaced when one is provided. This is a design from Getopt::Long and although I could circumvent this, I a not sure I should.
- error
  
  A string to be used to set an error by "check_class_data". Typically the string should provide meaningful information as to what the data should normally be. For example:
```
my $dict =
{
currency => { type => 'string', class => [qw(product)], name => 'currency', re => qr/^[a-z]{3}$/, error => "must be a three-letter iso 4217 value" },
};
```
- file
  
  This type will mark the value as a directory or file path and will become a Module::Generic::File object.
  
  This is particularly convenient when the user provided you with a relative path, such as:
```
./my_prog.pl --debug 3 --path ./here/
```
  And if you are not very careful and inadvertently change directory like when using File::Find, then this relative path could lead to some unpleasant surprise.
  
  Setting this argument type to file ensure the resulting value is a Module::Generic::File, whose underlying file or directory will be resolved to their absolute path.
- file-array
  
  Same as file argument type, but allows multiple value saved as an array. For example:
```
./my_prog.pl --skip ./not/here ./avoid/me/ ./skip/this/directory
```
  This would result in the option property skip being an array object containing 3 entries.
- max
  
  This is well explained in "Options with multiple values" in Getopt::Long
  
  It serves "to specify the minimal and maximal number of arguments an option takes".
- min
  
  Same as above
- re
  
  This must be a regular expression and is used by "check_class_data" to check the sanity of the data provided by the user. So, for example:
```
my $dict =
{
currency => { type => 'string', class => [qw(product)], name => 'currency', re => qr/^[a-z]{3}$/, error => "must be a three-letter iso 4217 value" },
};
```
  then the user calls your program with, among other options:
```
--currency euro
```
  would set an error that can be retrieved as an output of "check_class_data"
- required
  
  Set this to true or false (1 or 0) to instruct "check_class_data" whether to check if it is missing or not.
  
  This is an alternative to the "required" method which is used at an earlier stage, during "exec"
- type
  
  Type can be array, boolean, code, datetime, decimal, file, hash, integer, string, string-hash
  
  Type hash is convenient for free key-value pair such as:
```
--define customer_id=10 --define transaction_id 123
```
  would result for define with an anonymous hash as value containing customer_id with value 10 and transaction_id with value 123
  
  Type code implies an anonymous sub routine and should be accompanied with the attribute code, such as:
```
{ type => 'code', code => sub{ pod2usage(1); exit( 0 ) }, alias => '?', action => 1 },
```
  If type is boolean and the key is either with, without, enable, disable, their counterpart will automatically be available as well, such as you can do, as show in the excerpt in the synopsis above:
```
--enable-recurse --with-zlib
```
  Be careful though. If, in your dictionary, as shown in the synopsis, you defined without_zlib with a default value of true, then using the option --with-zlib will set that value to false. So in your application, you would need to check like this:
```
if( $opts->{without_zlib} )
{
    # Do something
}
else
{
    # Do something else
}
```
  Also as seen in the example above, you can add additional properties to be used in your program, here such as action that could be used to identify all options that are used to trigger an action or a call to a sub routine.
debug

This takes an integer, and is used to set the level of debugging. Anything under 3 will not provide anything meaningful.

METHODS

check_class_data

Provided with a string corresponding to a class name, this will check the data provided by the user.

Currently this means it checks if the data is present when the attribute required is set, and it checks the data against a regular expression if one is provided with the attribute re

It returns an hash reference with 2 keys: missing and regexp. Each with an anonymous hash reference with key matching the option name and the value the error string. So:

my $dict =
{
name => { type => 'string', class => [qw( person product )], required => 1 },
langs => { type => 'array', class => [qw( person product )], re => qr/^[a-z]{2}([_|-][A-Z]{2})?/, min => 1, default => [qw(en)] },
};

Assuming your user calls your program without --name and with --langs FR EN this would have "check_class_data" return the following data structure:

$errors =
{
missing => { name => "name (name) is missing" },
regexp => { langs => "langs (langs) does not match requirements" },
};

class

Provided with a string representing a property class, and this returns an hash reference of all the dictionary entries matching this class

classes

This returns an hash reference containing class names, each of which has an anonymous hash reference with corresponding dictionary entries

class_properties

Provided with a string representing a class name, this returns an array reference of options, a.k.a. class properties.

The array reference is a Module::Generic::Array object.

configure

This calls "configure" in Getopt::Long with the "configure_options".

It can be overriden by calling "configure" with an array reference.

If there is an error, it will return undef and set an "error" accordingly.

Otherwise, it returns the Getopt::Class object, so it can be chained.

configure_errors

This returns an array reference of the errors generated by Getopt::Long upon calling "getoptions" in Getopt::Long by "exec"

The array is an Module::Generic::Array object

configure_options

This returns an array reference of the Getopt::Long configuration options upon calling "configure" in Getopt::Long by method "configure"

The array is an Module::Generic::Array object

dictionary

This returns the hash reference representing the dictionary set when the object was instantiated. See "new" method.

error

Return the last error set as a Module::Generic::Exception object. Because the object can be stringified, you can do directly:

die( $opt->error, "\n" ); # with a stack trace

die( sprintf( "Error occurred at line %d in file %s with message %s\n", $opt->error->line, $opt->error->file, $opt->error->message ) );

exec

This calls "getoptions" in Getopt::Long with the "options" hash reference and the "parameters" array reference and after having called "configure" to configure Getopt::Long with the proper parameters according to the dictionary provided at the time of object instantiation.

If there are any Getopt::Long error, they can be retrieved with method "configure_errors"

my $opt = Getopt::Class->new({ dictionary => $dict }) || die( Getopt::Class->error );
my $opts = $opt->exec || die( $opt->error );
if( $opt->configure_errors->length > 0 )
{
    # do something about it
}

If any required options have been specified with the method "required", it will check any missing option then and set an array of those missing options that can be retrieved with method "missing"

This method makes sure that any option can be accessed with underscore or dash whichever, so a dictionary entry such as:

my $dict =
{
create_customer => { type => 'boolean', alias => [qw(create_client create_user)], action => 1 },
};

can be called by your user like:

---create-customer
# or
--create-client
# or
--create-user

because a duplicate entry with the underscore replaced by a dash is created (actually it's an alias of one to another). So you can say in your program:

my $opts = $opt->exec || die( $opt->error );
if( $opts->{create_user} )
{
    # do something
}

"exec" returns an hash reference whose properties can be accessed directly, but those properties can also be accessed as methods.

This is made possible because the hash reference returned is a blessed object from Getopt::Class::Values and provides an object oriented access to all the option values.

A string is an object from Module::Generic::Scalar

$opts->customer_name->index( 'Doe' ) != -1

A boolean is an object from Module::Generic::Boolean

An integer or decimal is an object from Text::Number

A date/dateime value is an object from DateTime

$opts->created->iso8601 # 2020-05-01T17:10:20

An hash reference is an object created with "_set_get_hash_as_object" in Module::Generic

$opts->metadata->transaction_id

An array reference is an object created with "_set_get_array_as_object" in Module::Generic

$opts->langs->push( 'en_GB' ) if( !$opts->langs->exists( 'en_GB' ) );
$opts->langs->forEach(sub{
    $self->active_user_lang( shift( @_ ) );
});

Whatever the object type of the option value is based on the dictionary definitions you provide to "new"

get_class_values

Provided with a string representing a property class, and this returns an hash reference of all the key-value pairs provided by your user. So:

my $dict =
{
create_customer => { type => 'boolean', alias => [qw(create_client create_user)], action => 1 },
name        => { type => 'string', class => [qw( person product )] },
created     => { type => 'datetime', class => [qw( person product )] },
define      => { type => 'string-hash', default => {} },
langs       => { type => 'array', class => [qw( person product )], re => qr/^[a-z]{2}([_|-][A-Z]{2})?/, min => 1, default => [] },
currency    => { type => 'string', class => [qw(product)], name => 'currency', re => qr/^[a-z]{3}$/, error => "must be a three-letter iso 4217 value" },
age         => { type => 'integer', class => [qw(person)], name => 'age', },
};

Then the user calls your program with:

--create-user --name Bob --age 30 --langs en ja --created now

# In your app
my $opt = Getopt::Class->new({ dictionary => $dict }) || die( Getopt::Class->error );
my $opts = $opt->exec || die( $opt->error );
# $vals being an hash reference as a subset of all the values returned in $opts above
my $vals = $opt->get_class_values( 'person' )
# returns an hash only with keys name, age, langs and created

getopt

Sets or get the Getopt::Long::Parser object. You can provide yours if you want but beware that certain options are necessary for Getopt::Class to work. You can check those options with the method "configure_options"

missing

Returns an array of missing options. The array reference returned is a Module::Generic::Array object, so you can do thins like

if( $opt->missing->length > 0 )
{
    # do something
}

options

Returns an hash reference of options created by "new" based on the dictionary you provide. This hash reference is used by "exec" to call "getoptions" in Getopt::Long

parameters

Returns an array reference of parameters created by "new" based on the dictionary you provide. This hash reference is used by "exec" to call "getoptions" in Getopt::Long

This array reference is a Module::Generic::Array object

required

Set or get the array reference of required options. This returns a Module::Generic::Array object.

usage

Set or get the anonymous subroutine or sub routine reference used to show the user the proper usage of your program.

This is called by "exec" after calling "getoptions" in Getopt::Long if there is an error, i.e. if "getoptions" in Getopt::Long does not return a true value.

If you use object to call the sub routine usage, I recommend using the module curry

If this is not set, "exec" will simply return undef or an empty list depending on the calling context.

ERROR HANDLING

This module never dies, or at least not by design. If an error occurs, each method returns undef and sets an error that can be retrieved with the method "error"

AUTHOR

Jacques Deguest <jack@deguest.jp>

COPYRIGHT & LICENSE

You can use, copy, modify and redistribute this package and associated files under the same terms as Perl itself.

To install Getopt::Class, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Getopt::Class

CPAN shell

perl -MCPAN -e shell
install Getopt::Class

For more information on module installation, please visit the detailed CPAN module installation guide.

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