About permissions in SmallWiki

Hi lukas I restarted to read SmallWiki code because I lost the changes of my previous image. Anyway, if I understand correctly there are permissions and users. Permission are grants to perform action. A role contains a list of permissions. A user play certain roles. Before performing an action, sw checks whether the user has the right permissions obtained by playing a certain role. Now the structure itself is not involved, this means that if I want to have a special page that only a certain person can edit but everybody else cannot I have to create a special role for that. Am I correct? Or is it possible to grant permission at the instance level like a page? For example how do I say that a folder can only be edited by admin or User X, or a person playing the role editFolderX? Stef