On Thu, Nov 26, 2009 at 10:46 AM, Ovid <publiustemp-catal...@yahoo.com> wrote:
> I have two attributes, 'xml' and 'xml_file' for an object. One or the other
> must be supplied, but not both.
>
> Must I validated this in BUILD or is there another way of doing this?
Well, I would use a trigger and predicate. Triggers are fired AFTER
the attribute is set in the constructor or with an explicit call to
the setter. I don't like to have BUILD unless I need it, and this will
check runtime sets too.
So you have something like
has 'foo' => (
isa => 'Int'
, is => 'rw'
, predicate => 'has_foo'
, trigger => \&consistancy
);
has 'bar' => (
isa => 'Int'
, is => 'rw'
, predicate => 'has_bar'
, trigger => \&consistancy
);
sub consistancy {
my $self = shift;
throw_error('OVID SAYS NO NO')
if $self->has_foo && $self->has_bar
;
}
--
Evan Carroll
System Lord of the Internets
http://www.evancarroll.com
