SYNOPSISAdd the ``SetOnce'' trait to attributes:
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!
DESCRIPTIONThe '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.
AUTHORRicardo SIGNES <[email protected]>
COPYRIGHT AND LICENSEThis 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.