EDIT - Solved, thanks to everyone who replied! Right, so I'm currently setting up a mall and making a section that sells enchanted books. I understand that I need to make [SLOT] signs to sell the book but I'm still a little confused around them, even after reading the wiki. From what I understand, say I want to sell an unbreaking III enchanted book with a [SLOT 1] sign, I would put an unbreaking III book in slot one of the chest and fill the rest of the chest with unbreaking III enchanted books too. The book in slot one of the chest would be used as a reference to tell the sign that this item is the only thing that should be sold from this chest because it is in slot one. When all the books get bought, it would say that the shop is sold out when you try to buy but in reality, the unbreaking III book in slot one is protected from being bought because it's used as a reference and the shop would not know what to sell and buy without it. Is this correct?
I think it would only read from slot 1. (I've never really used that method so not 100% sure) An easier method I've used before would be to fill 53 spots of the chest with 1 dirt and leave slot 1 open. Behind that chest put a hopper going into it. On top of that hopper place a chest. Fill that chest with unbreaking 3 books. Then slot 1 would always be restocked.
That would work as long as all the books have the same ID (i.e. same durability, same enchantments). It would sell everything UNTIL the item in Slot 1 is the last item, when it will sell that as well.
Yea, all the same item in one chest, I was just wondering it it would sell the last one in slot one when all the others have gone or keep it as a reference for what to sell into the chest afterwards to prevent people from cheating the system and selling me say, dirt blocks for instance for the full price I would pay for a book because there would be nothing in the chest to tell it what it should buy and what it should not.
The slot approach is dynamic. The moment the item in the assigned slot changes then the whole chest sell/buy setup changes. So say you have your book in slot 1 and some extras in the chest. Then you have several diamonds in other slots. At one time you decide to replace the book in slot 1 with a diamond. Once you've done that the whole system will now swap to diamonds. So if you were selling 1 [slot 1] item for, say, 750r then you'd now be selling 1 diamond for 750r. This trick can even be used to sell two different items from 1 (double)chest. Edit: So, in case the last item got sold the whole system halts. No one will be able to sell you anything because the 'identifier' for the slot sign is then gone.
