Stupid Moose Tricks: Being Your Own Exception Class
I discovered (by accident) that in Moose you can be your own exception class:
package Local::Iam::MyOwn::Exception;use Moose;
with 'Throwable';sub ork {
my ($self, $cow) = @_;if ($cow ne 'cow') {
$self->throw("Need a 'cow', here!");
}return ('ork', 'ork', 'ork');
}
package main;my $lime = Local::Iam::MyOwn::Exception->new();
print join(' .. ', $lime->ork('cow')) . "\n";
print join(' .. ', $lime->ork('horse')) . "\n";
If you run this, you will get output confirming that the class is both a worker (or at least a cow-orker) and an exception:
ork .. ork .. ork
throw called on Throwable object with arguments at /usr/lib/perl5/site_perl/5.14/Throwable.pm line 33.
Throwable::throw(Local::Iam::MyOwn::Exception=HASH(0x8006c118), "Need a 'cow', here!") called at x.pl line 9
Local::Iam::MyOwn::Exception::ork(Local::Iam::MyOwn::Exception=HASH(0x8006c118), "horse") called at x.pl line 23
Writing a class that is its own exception means not writing a separate exception class, which might save you (a little) time.
(And remember -- you can 'ork' a cow, but you cannot 'ork' a horse. This code proves it.)
Perl/CPAN user since 1992.
There's nothing Moose specific here. Any package can be used to throw exceptions. Look ma! Strict exceptions!
use strict; package strict { use overload q[""] => sub { $_[0][0] }; sub throw { my $c = shift; die(bless \@_, $c) } } strict->throw("not strict enough!");(Stack traces are left as an exercise for the reader.)
If you want to save time writing exception classes, I recommend looking at Throwable::Factory instead.