Is there a plan to allow Comparisons between Presemtations ?

Is there a plan to have functionality that would allow you to configure required relationships between presentations (fields) ? A few examples would be:

1 - Date field X must be ... >, >=, <, <=, = ... Date field Y

2 - Assume Field A has been defined and has X, Y and Z as possible values. Allow person to define field B such that it MUST (or MUST NOT) be populated if Field A = X or Z ... (and therefore NOT if Field A = Y)

Thanks,