"Does this also count for data setup? Eg you have a function that returns an array of Strings that should be used for this table view and say the tableview: Use this function as data source?"
No. If by "tableview" you mean something like a listbox, the items in the list are also structs stored in linked lists.
EDIT: But you can of course write your own function that puts an array of strings into that linked list.

But you can do stuff like I showed with the editbox that only accepts odd ASCII codes. You can even access the input string so you can make it always write capital letters, although you typed in lower-case letters. And there is the button Condition function.