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MooseX-Extended-0.21
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/ MooseX::Extended::Manual::Construction

NAME

MooseX::Extended::Manual::Construction - Objected construction for MooseX::Extended

VERSION

version 0.21

OBJECT CONSTRUCTION

The normal new, BUILD, and BUILDARGS functions work as expected. However, we apply MooseX::StrictConstructor to avoid this problem:

my $soldier = Soldier->new(
    name   => $name,
    rank   => $rank,
    seriel => $serial, # should be serial
);

By default, misspelled arguments to the Moose constructor are silently discarded, leading to hard-to-diagnose bugs. With MooseX::Extended, they're a fatal error.

If you need to pass arbitrary "sideband" data, explicitly declare it as such:

param sideband => ( isa => HashRef, default => sub { {} } );

Naturally, because we bundle MooseX::Extended::Types, you can do much finer-grained data validation on that, if needed.

FUNCTIONS

The following two functions are exported into your namespace.

param

param name => ( isa => NonEmptyStr );

A similar function to Moose's has. A param is required. You may pass it to the constructor, or use a default or builder to supply this value.

The above param definition is equivalent to:

has name => (
    is       => 'ro',
    isa      => NonEmptyStr,
    required => 1,
);

If you want a parameter that has no default or builder and can optionally be passed to the constructor, just use required => 0.

param title => ( isa => Str, required => 0 );

Note that param, like field, defaults to read-only, is => 'ro'. You can override this:

param name => ( is => 'rw', isa => NonEmptyStr );

Otherwise, it behaves like has. You can pass in any arguments that has accepts.

# we'll make it private, but allow it to be passed to the constructor
# as `name`
param _name   => ( isa => NonEmptyStr, init_arg => 'name' );

field

field created => ( isa => PositiveInt, default => sub { time } );

A similar function to Moose's has. A field is never allowed to be passed to the constructor, but you can still use default or builder, as normal.

The above field definition is equivalent to:

has created => (
    is       => 'ro',
    isa      => PositiveInt,
    init_arg => undef,        # not allowed in the constructor
    default  => sub { time },
    lazy     => 1,
);

Note that field, like param, defaults to read-only, is => 'ro'. You can override this:

field some_data => ( is => 'rw', isa => NonEmptyStr );

Otherwise, it behaves like has. You can pass in any arguments that has accepts.

WARNING: if you pass field an init_arg with a defined value, The code will croak. A field is just for instance data the class uses. It's not to be passed to the constructor. If you want that, just use param.

Later, we'll add proper exceptions.

Lazy Fields

Every field is lazy by default. This is because there's no guarantee the code will call them, but this makes it very easy for a field to rely on a param value being present.

Every param is not lazy by default, but you can add lazy => 1 if you need to.

AUTHOR

Curtis "Ovid" Poe <curtis.poe@gmail.com>

COPYRIGHT AND LICENSE

This software is Copyright (c) 2022 by Curtis "Ovid" Poe.

This is free software, licensed under:

The Artistic License 2.0 (GPL Compatible)