Concept-Oriented Blog

As programmers, we know that any object has a representative, called reference. For decades objects have relied exclusively on references provided by the compiler which in turn used the underlying environment, some kind of standard library or middleware for their generation and management. For example, the compiler could use global heap where allocated objects are represented by a system-specific memory handle. Objects could be represented by remote references generated by EJB container like JBoss or WebLogic. In Java, references are generated by JVM. Other interpreters are using their own run-time environment and hence their own specific references. Thus most contemporary programming languages have one common property:

References are not integral part of the program and cannot be adapted to the purposes of this application and this problem domain

In other words, in conventional programming languages we are destined to use only standard references and their access mechanisms provided by the available hardware, OS, middleware or library. There is no easy possibility to develop application-specific references for this concrete domain as integral part of this program.

The system can be then viewed as divided into two layers:

1. The first layer is responsible for generating/managing references and providing object access procedure
2. The second layer is the program itself where these references are used independent of the peculiarities of the first layer

Almost all exiting programming paradigms isolate these two layers so that programming is reduced to the second layer. This means that the programmer can develop objects and their methods but is not able to influence how these objects are represented and how they will be accessed. Concept-oriented programming (CoP) is a novel approach to programming which changes this view and allows for describing both layers within one program. CoP makes references first-class citizens of the object world by retaining the transparency of access (isolation of the layers). References and objects have equal rights in a concept-oriented program. In particular, CoP is based on using a new programming construct, called concept, which is defined as a couple of two classes: one reference class and one object class. As a consequence, both references and objects have arbitrary domain-specific structure and behaviour. CoP also uses inclusion relation instead of classical inheritance. (Concepts and inclusion generalize classes and inheritance, respectively.)

One of the main advantages of CoP is that the programmer can develop domain-specific containers with a virtual address space where objects will live. In other words, the programmer can implement functions which normally belong to hardware, OS, middleware, run-time environment or a library. Another interesting application consists in modeling cross-cutting concerns.