http://qs321.pair.com?node_id=486368

rvosa has asked for the wisdom of the Perl Monks concerning the following question:

Dear monks,

I am trying to understand how to use Exception::Class in a large-ish multimodule application. As part of the set of modules I made one package where I am planning to define all exceptions, i.e.:
package Bio::Phylo::Exceptions; use Exception::Class ( 'Bio::Phylo::Exceptions', 'Bio::Phylo::Exceptions::BadNumber' => { isa => 'Bio::Phylo::Exceptions' }, 'Bio::Phylo::Exceptions::BadString' => { isa => 'Bio::Phylo::Exceptions' }, 'Bio::Phylo::Exceptions::BadFormat' => { isa => 'Bio::Phylo::Exceptions' }, 'Bio::Phylo::Exceptions::ObjectMismatch' => { isa => 'Bio::Phylo::Exceptions' } ); 1;
So then, elsewhere in the modules, there might be OO getters and setters like this:
use Scalar::Util qw(looks_like_number); sub set_number { my ( $self, $number ) = @_; looks_like_number $number ? $self->{'NUMBER'} = $number : Bio::Phylo::Exceptions::BadNumber->throw(error => 'bad number'); }
And then the user has to go through a contortion like:
# try eval { $obj->set_number(sdf7897) }; # catch if (UNIVERSAL::isa($@,'Bio::Phylo::Exceptions::BadNumber')){ # do something }
Is that how it works? Or are the exceptions caught inside the object methods?

Pardon my ignorance, but I've never worried about this before, and I wish to learn.

Thank you!