How to debug Perl (according to Exercism)

So in the hello world exercise for Perl, there’s this note:

" How to debug

When a test fails, a message is displayed describing what went wrong. If you would like additional output, you can use the subroutine ::YYY() around the code you would like to inspect. (:: is a shortcut for main::). This subroutine is part of the XXX module."

What does this actually end up looking like? I’ve not been successful so far and most of my searches are returning results for date-time content or generic strings.

For example, in the ETL exercise, if you wanted to debug the input data:

sub transform ($data) {
    ::YYY($data);
}

In the online test runner, the tests will contain a section called ‘Your Output’, which in this case would look something like this:

---
'1':
- A
- E
- I
- O
- U
...

at /mnt/exercism-iteration/t/../lib/ETL.pm line 9

1 Like

Ah! Awesome, thank you.