I haven't even done "many" changes to perl5db.pl to begin with! ;-)

It's been less than 20 lines in total (including the AppleScript ones shown above), and in only 3 places.

And how would aliases help me? Aliases can't seem to add actual functionality – they only alias existing functionality for shorthand invocation as far as I can tell. But I actually need additional functionality.

Do you happen to know where to look for the IDE interface? I hadn't noticed it so far. But in that case I would have had to create a separate intermediate process; Sounds like a lot of additional complexity...

Of course I agree that that might be cleaner, if it can actually achieve what I need.

Emacs wouldn't be an advantage for me – it would introduce a whole additional editor environment with different usage, different presentation and a substantial learning curve. The BBEdit solution actually works surprisingly well already.

Interesting information and hints from you and above, in any case. While I might eventually end up changing things from where I'm now, I'm quite stoked about the level of usability I've managed to wring out of this provisional solution already with a minimum of customization.

Many thanks to everybody anyway! :-)