1.2.5 Conclusion on merits

From the above discussion, it is clear that action semantics improves semantic notation in many aspects:

• Readability.
  The readability of action semantics description comes from its informal appearance. When a reader goes through a description, he/she can easily understand what is going on without reconstructing semantic concepts from obscure formulas.
• Modularity and extensibility.
  In action semantics, semantic functions and entities are not so entangled with each other than in denotational semantics. A module imports another one only when it requires its functionality. An action is dependent only on the data entities that it performs operations on, without noticing the existence of the others. Universal combinators are primitively defined and thus can be viewed as in another separate module. In such an organization, change on the described programming language only requires proportional change on its description.
• Reusability.
  Because the description is divided into several relatively self-contained modules and the definition of each module is usually divided into multiple files, part of the existing description can be reused in another language, just to be imported by a new one. This is extremely desirable, since contemporary programming languages share a lot of popular ideas and concepts.