[Oberon] Type compatibility in Oberon

[Andreas Pirklbauer]

   > Oberon as it is defined in the report leaves some parts needed for low level programming to the implementation.

At the heart the problem appears to be two-fold: a) the language leaves certain things undefined, and b) in order to truly implement an entire system like the Oberon system, one has to cheat (at least a little). For example, today it is not guaranteed that a program compiled with two different implementations of the same report behave in the same way.