IS IDL A SPECIFICATION LANGUAGE, AN IMPLEMENTATION LANGUAGE, OR BOTH?
A specification language. IDL makes a strong separation between the specification of an object and the implementation of that object. Programmers who use the interface of an object have no idea whatsoever how that object is implemented. For example, the object doesn t even need to be implemented using an OO programming language. This is called Separation of Interface from Implementation, and is a very important concept in OO in general and in CORBA in particular.