I thought that way until I worked with iPython for a while (back when it was primarily a clever REPL, and didn&#x27;t really have the &quot;notebooks&quot; feature at all, yet, I don&#x27;t think...this was back when it was new). Having a really strong REPL when debugging is like having a rocket, when you&#x27;re used to having a hot air balloon.<p>I&#x27;ve always been bothered by the weakness of Perl REPLs. It&#x27;s only recently started to improve (in the past five years or so) for Perl 5, but there are some decent ones, though nothing even in the same league as iPython.