my $base_class = '...'; # base class for exceptions
my $error_class = '...'; # my error class

sub rethrow(;$) {
	my $e = @_ ? $_[0] : $@;

	die $e
		if blessed( $e ) && $e->isa( $base_class );

	die $error_class->new( $e );
}

sub try(&) {
	my $code = $_[0];

	eval {
		local $SIG{__DIE__} = \&rethrow;
		&$code();
	};

	$@;
}