This follows from my previous question about structured Moose types. I apologize for the question. I wanted me to include all the necessary details.
MyApp::Type::Fielddefines a structured type. I use coercion to make its attribute valueeasier to set from my class Person(see Example below). Please note that in my real application, where the field type is used not only for the person’s name, I also force you to HashRef.
I also need to set attributes MyApp::Type::Field sizeand requiredread only from MyApp::Personduring build. I can do this using the build method, but this is not called if coercion is used, since my coercion creates a new object directly, without using the builder method.
I can get around this by adding a method modifier aroundto MyApp::Person(see example below), but it seems messy. The method modifier aroundis called frequently, but I only need to set read-only attributes.
Is there a better way to do this while maintaining coercion? The class MyApp::Type::Fieldcan not be initialized size, and requiredthe default or builders, as he does not know what the value should be.
, around.
MyApp::Type::Field
coerce 'MyApp::Type::Field'
=> from 'Str'
=> via { MyApp::Type::Field->new( value => $_ ) };
has 'value' => ( is => 'rw' );
has 'size' => ( is => 'ro', isa => 'Int', writer => '_set_size', predicate => 'has_size' );
has 'required' => ( is => 'ro', isa => 'Bool', writer => '_set_required', predicate => 'has_required' );
MyApp::Person
has name => ( is => 'rw', isa => 'MyApp::Type::Field', lazy => 1, builder => '_build_name', coerce => 1 );
sub _build_name {
print "Building name\n";
return MyApp::Type::Field->new( size => 255, required => 1 );
}
MyApp::Test
print "Create new person with coercion\n";
my $person = MyApp::Person->new();
print "Set name\n";
$person->name( 'Joe Bloggs' );
print "Name set\n";
printf ( "Name: %s [%d][%d]\n\n", $person->name->value, $person->name->size, $person->name->required );
print "Create new person without coercion\n";
$person = MyApp::Person->new();
print "Set name\n";
$person->name->value( 'Joe Bloggs' );
print "Name set\n";
printf ( "Name: %s [%d][%d]\n\n", $person->name->value, $person->name->size, $person->name->required );
Create new person with coercion
Set name
Name set
Name: Joe Bloggs [0][0]
Create new person without coercion
Set name
Building name
Name set
Name: Joe Bloggs [255][2]
around MyApp::Person , size required:
around 'name' => sub {
my $orig = shift;
my $self = shift;
print "Around name\n";
unless ( $self->$orig->has_size ) {
print "Setting size\n";
$self->$orig->_set_size( 255 );
};
unless ( $self->$orig->has_required ) {
print "Setting required\n";
$self->$orig->_set_required( 1 );
};
$self->$orig( @_ );
};
sub _build_name {
print "Building name\n";
return MyApp::Type::Field->new();
}
MyApp::Test, size required .
Create new person with coercion
Set name
Around name
Building name
Setting size
Setting required
Name set
Around name
Setting size
Setting required
Around name
Around name
Name: Joe Bloggs [255][3]
Create new person without coercion
Set name
Around name
Building name
Name set
Around name
Around name
Around name
Name: Joe Bloggs [255][4]
daotoad's MyApp::Person, Str MyApp::Type::Field . , , for. .
handles, $person->get_first_name $person->first_name->value. , :
package MyApp::Type::Field;
use Moose;
has 'value' => (
is => 'rw',
);
has 'size' => (
is => 'ro',
isa => 'Int',
writer => '_set_size',
);
has 'required' => (
is => 'ro',
isa => 'Bool',
writer => '_set_required',
);
__PACKAGE__->meta->make_immutable;
1;
package MyApp::Person;
use Moose;
use Moose::Util::TypeConstraints;
use namespace::autoclean;
{
my $attrs = {
title => { size => 5, required => 0 },
first_name => { size => 45, required => 1 },
last_name => { size => 45, required => 1 },
};
foreach my $attr ( keys %{$attrs} ) {
my $subtype = 'MyApp::Person::' . ucfirst $attr;
subtype $subtype => as 'MyApp::Type::Field';
coerce $subtype
=> from 'Str'
=> via { MyApp::Type::Field->new(
value => $_,
size => $attrs->{$attr}{'size'},
required => $attrs->{$attr}{'required'},
) };
has $attr => (
is => 'rw',
isa => $subtype,
coerce => 1,
writer => "set_$attr",
handles => { "get_$attr" => 'value' },
default => sub {
MyApp::Type::Field->new(
size => $attrs->{$attr}{'size'},
required => $attrs->{$attr}{'required'},
)
},
);
}
}
__PACKAGE__->meta->make_immutable;
1;
package MyApp::Test;
sub print_person {
my $person = shift;
printf "Title: %s [%d][%d]\n" .
"First name: %s [%d][%d]\n" .
"Last name: %s [%d][%d]\n",
$person->title->value || '[undef]',
$person->title->size,
$person->title->required,
$person->get_first_name || '[undef]',
$person->first_name->size,
$person->first_name->required,
$person->get_last_name || '[undef]',
$person->last_name->size,
$person->last_name->required;
}
my $person;
$person = MyApp::Person->new(
title => 'Mr',
first_name => 'Joe',
last_name => 'Bloggs',
);
print_person( $person );
$person = MyApp::Person->new();
$person->set_first_name( 'Joe' );
$person->set_last_name( 'Bloggs' );
print_person( $person );
1;
Title: Mr [5][0]
First name: Joe [45][6]
Last name: Bloggs [45][7]
Title: [undef] [5][0]
First name: Joe [45][8]
Last name: Bloggs [45][9]