loading set from file

[SilverWarior]

it's a byte not a string. I just let the compiler number them

Automatic numbering for such things isn't verry suitable as you can quickly change the numbering order by changing the set itself. This means that after you change the set your program will no longer be able to load older savegame.
Using my aproach also has advantage of you being albe to leave some identifier numbers unused so you can use them in the future and therefore avoid changing existing ones when adding new ones.

EDIT: As for sets their primarry use is to add predefined identifiers for some properties. And yes in memory set elements are saved just as Indexes of set elements. You can consider sets as bunch od Constants of same type grouped together.