G'day bliako,

There is no requirement for $class to be a real class, have length, or even be present. See bless for details.

The use of ref in your posted code is not the best choice: the doco explains issues. It would be much better to use the blessed function of the builtin module Scalar::Util.

Here's an example of usage. My perle alias captures all sorts of problems.

$ alias perle
alias perle='perl -Mstrict -Mwarnings -Mautodie=:all -MCarp::Always -E
+'
[download]

$ perle '
    use Scalar::Util "blessed";

    for (1, 2) {
        say "Run: $_";
        my $ret = foo();
        my $err = blessed $ret;

        if (defined $err) {
            say qq{Error "$err" detected};
            say qq{Code: $ret->[0]};
            say qq{Errstr: $ret->[1]};
        }
        else {
            say qq{Success!};
            say for @$ret;
        }
    }

    sub foo {
        state $error = 0;
        my $retval;

        if ($error) {
            $retval = bless [0, "error was ..."] => "YouveGotError";
        }
        else {
            $retval = [42, 43];
        }

        $error ^= 1;
        return $retval;
    }
'
Run: 1
Success!
42
43
Run: 2
Error "YouveGotError" detected
Code: 0
Errstr: error was ...
[download]