On Tue, Jul 22, 2008 at 10:18 AM, Paul Driver <[EMAIL PROTECTED]> wrote:
> I think the major benefit of the "around" trigger was being able to filter
> the value going into the setter. I don't have any use case for 'before'
> that couldn't be accomplished with older "standard" (after) triggers - so
> some kind of setter-filter (needs a better name) would probably do just as
> well. That could be done by a MooseX, potentially.
Anything that depends on the old value would be a use case for
"before". For example, one of my uses would be:
has type => (
trigger => {
before => sub {
$registry->unregister_tile_by_type($_[0], $_[1]);
},
after => sub {
$registry->register_tile_by_type($_[0], $_[1]);
},
},
);
before is also useful for additional validation. You want to throw the
exception *before* you set an invalid value.
Shawn
