note adrianh <p>I'd add another vote for [cpan://Exception::Class]. It allows exceptions classes to be declared quickly and easily and has become my fave since discovering its existance.</p> <p>I tend to have a single module that declares all my exceptions. So for my Foo application I'd have something like:</p> <code> package Foo::Exceptions; use strict; use warnings; use Exception::Class ( 'Foo::Exception::DBI' => { description => 'DBI Error', # error => $DBI::errstr, }, 'Foo::Exception::DBI::Dupe' => { description => 'Duplicate key', isa => 'Foo::Exception::DBI', # error => name of duplicate key, }, 'Foo::Exception::Dupe' => { description => 'Duplicate entry', fields => [ 'name' ], # error => value of duplicate field }, # etc. ); </code> <p>Comments are because [cpan://Exception::Class] objects have a default "error" field and I like to document what that should be used for where I declare the class.</p> <p>Throw exceptions like this:</p> <code> Foo::Exception::DBI->throw($DBI::errstr) Foo::Exception::Dupe->throw(name => $name, error => $value); </code> <p>Because of the closure issues [id://230804|raised by thraxil], I use the <code>eval / if </code> idiom instead of any of the modules that provide extra try/catch syntax.</p> <code> eval {$foo->something_that_might_die}; if (ref($@)) { if ($@->isa('Foo::Exception::Dupe') ) { warn "duplicate entry ", $@->name, " ($@)\n"; undef $@; }; }; die $@ if $@; </code> 230799 230807