Possible array implementation

This is just a demo branch, where I've tried to sketch a possible array implementation. 
Problems:
It is still unclear to me whether we have support recursion. Is it possible that an array contains another array or is it just a recursion level of one? 
I've added a MessageItemId to select a value from an array, but this requires that we have to let SHCData:SHCData know, what item to choose, which changes the interface in way that is undesired...

There has to be anything better...