How can I prevent Perl Moose Read-Only Attributes being set upon a call to new?
-
06-07-2019 - |
Question
I would like to simply declare a read only attribute in Moose that cannot be initialized in a call to new. So after declaring the following:
package SOD::KuuAnalyze::ProdId;
use Moose;
has 'users' => (isa => 'ArrayRef[Str]', is => "ro");
1;
I do not want the following to work:
my $prodid = SOD::KuuAnalyze::ProdId->new(users => ["one", "two"]);
Solution
Use the init_arg
attribute configuration (see "Constructor parameters" in Moose::Manual::Attributes):
package SOD::KuuAnalyze::ProdId;
use Moose;
has 'users' => (
isa => 'ArrayRef[Str]', is => "ro",
init_arg => undef, # do not allow in constructor
);
1;
OTHER TIPS
How about
package SOD::KuuAnalyze::ProdId;
use Moose;
has 'users' => ( isa => 'ArrayRef[Str]', is => 'ro', init_arg => undef, default => sub { [ 'one', 'two' ] } );
Setting the init_arg
to undef
seems to be necessary to disallow setting the attribute from the constructor.
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