> Debuggers could add conditional expressions, but then they'd be re-inventing WRITE statements anyhow.
SWI-Prolog's debugger can be invoked conditionally whenever you want from inside your running application. I've used it many times, and the code is simply:
(Condition -> gtrace ; true)
It's true that you could stick a write there, but you would have to think about what pieces of data you will need. Your mileage may vary. I've found this style a
lot more useful than "traditional" debuggers where you set breakpoints beforehand and hope you hit them, as you say.
> As far as the nearby statement that maybe I didn't learn dissection correctly, that may indeed be the case
The point was more specifically that you didn't learn Prolog properly (or at all) and don't realize that it forces you to dissect your code. As I said, in Prolog you cannot nest loops. You cannot nest loops. It's hard to write a big non-dissected piece of code if you cannot nest loops.
> perhaps the real problem is that nobody knows how to TEACH functional/logical programming right
I agree with regards to logic programming. We need better free tutorials. I don't particularly like the linked one, it feels like it doesn't start at a beginner's level. I would be interested if anyone who didn't know any Prolog before has managed to learn Prolog from it.