If hoppers (or a dispenser) could push enchanted books/book and quill into lecterns, and hoppers could suck the book back out, then lecterns could be used in sorting systems to separate this item type.

I don't know that the current lectern implementation is because it seems to be able to 'hold' a book and has some redstone interaction (comparator for reading page). So perhaps this is viable. It seems like a more likely candidate for this type of behaviour than the bookcase.

Additionally, you could change comparator logic from lecterns to allow enchanted book sorted. E.g.

• A comparator in compare mode outputs signal strength based on enchanting level
• A comparator in subtract mode is used to compare against another lectern to the side, if the other lectern has the same enchantment it output signal, if not, no signal. I.e. if lectern A being compared (subtract) has a fortune book in it, and the 'subtract from' lectern (B) as fortune, a redstone output is produced, if B does not have a fortune enchantment, then no redstone output is produced.

This would allow a complete enchanted book sorting system to be created.

Comparators changing behaviour based on whether the book is enchanted or not sounds a bit weird, but maybe that doesn't matter

Comparators changing behaviour based on whether the book is enchanted or not sounds a bit weird, but maybe that doesn't matter

Also what would the gui show if you interacted with a lectern with an enchanted book?

Maybe in creative mode, you can modify the enchantmen(s) and level(s) of the enchantment(s), whereas in survival mode you cannot open it.