LANSA's RDML (Rapid Development and Maintenance Language) allows you to create a High Level Application Definition or abstraction of your business application. This definition is independent of the operating platform. Defining logic with a 4GL makes your programs independent of the 3GL layer. A 4GL will eventually generate some type of 3GL code which is compiled and executed, but you never need to modify the generated 3GL. In fact, it should not matter which 3GL is used. A High Level Application Definition should allow you to generate or regenerate the same applications in different languages to make your applications portable.
This is why you use a 4GL/RDML:
As your business and technology changes, LANSA's RDML protects your application programming efforts.