Class diversity support in object-oriented languages

representation of internal version state Correct_State Give_State state of version 1 state of version 2 state of version 3 Give_State Give_State Correct_State Correct_State Figure 2. Faulty version recovery based on the intermediate state representation. We can envisage several approaches to presenting the internal states of different versions in a uniform way. One idea is to use components of only basic types (e.g. real, integer, boolean, string) which are kept in some record types known to all version programmers. Another approach could be to use the internal data of one of the versions as this intermediate data representation. Finally, a unified class could be