4 Action semantics at the meta-model level

Instead of merely used to specify the dynamic behavior of the model execution, action semantics, similar to a programming language in some sense, is also capable of restructuring the model design at the meta-modelling level.

When action semantics descriptions are employed at design time, they are executed in the meta-model instead of the model. The model may not be finished at that time, so it is impossible to execute the model. The action semantics description running on the meta-model is to automatically restructure the design and possibly make it conform to a certain design pattern or refactor it [SPH⁺01].

Using action semantics at this level enhances the functionality of the meta-model. However, it is just introduced to facilitate the design work, without which designers are still able to make the same modification manually.