MooseX::SetOnce - write-once, read-many attributes for Moose

       Ricardo SIGNES <rjbs@cpan.org>

       This software is copyright (c) 2013 by Ricardo SIGNES.

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

perl v5.34.0                                       2022-06-15                               MooseX::SetOnce(3pm)

       The 'SetOnce' attribute lets your class have attributes that are not lazy and not set, but that cannot be
       altered once set.

       The logic is very simple:  if you try to alter the value of an attribute with the SetOnce trait, either
       by accessor or writer, and the attribute has a value, it will throw an exception.

       If the attribute has a clearer, you may clear the attribute and set it again.

       MooseX::SetOnce - write-once, read-many attributes for Moose

       Add the "SetOnce" trait to attributes:

         package Class;
         use Moose;
         use MooseX::SetOnce;

         has some_attr => (
           is     => 'rw',
           traits => [ qw(SetOnce) ],
         );

       ...and then you can only set them once:

         my $object = Class->new;

         $object->some_attr(10);  # works fine
         $object->some_attr(20);  # throws an exception: it's already set!

       version 0.200002