"Selector must be of an ordinal type, float or string"

[drkameleon]

I'm trying to write a "switch-case" statement like:
    
    
    case MyVal
        of...
    
    
    Run

where MyVal is of type "Value" (which is defined as a uint64).

How do I make the compiler interpret it right (since an uint64 is obviously an 
ordinal type)?