The idea of automating software development with modeling and code generation tools is by no means new, but in many cases the adoption and implementation of this idea has been less than perfect. The main problem with traditional modeling tools has been the inflexibility of their language and generator support. Fixed languages and generators may be fine when the developers are able to use them exactly as they are, but it becomes a problem when the need for project or organization specific extensions or changes arises.

To address this problem, language workbenches with customizable language and generator support have emerged. The main benefit a language workbench like MetaEdit+ provides is the possibility to create and use modeling languages specifically designed for developing a particular kind of system. Such languages are usually referred to as domain-specific modeling languages and their usage as domain-specific modeling (DSM).

In traditional modeling tools the languages are aimed for as general use as possible and therefore they can provide little specific help for any specific application domain. In contrast, DSM languages are aimed only at a certain domain or intended use. Often, DSM languages are constructed from the concepts and terminology found from the domain itself. For example, if we were to create a modeling language for designing digital wristwatches, the suitable candidates for language constructs would be such things as time units and their arithmetic operations or user-interface elements like buttons or icons. Using these kinds of concepts results in languages that are natural for their domains and thus easier to learn and use for the developers. Furthermore, with DSM it is possible to capture both static and dynamic aspects of the modeled entity, which makes it possible to generate 100% code for the final product automatically. Because of this, organizations adopting DSM can look forward to a major increase in their productivity.

DSM languages alone, however, are not enough. To exploit their possibilities fully, support environments with proper editing and code generation features are needed. Traditionally, building such environments – effectively bespoke modeling tools – has been expensive and therefore possible only for large organizations. Language workbenches have changed this: with such tools it is now possible to create the DSM environments very quickly and inexpensively, bringing benefits to small and large organizations alike.

The detailed explanation of the process for creating a complete DSM environment is out of the scope for this manual, but the basic principles are simple enough to be mentioned here. The critical success factor for building such an environment is the domain knowledge possessed by the organization’s expert developers. Therefore, it is their task to define the language and code generator support. In practice this means that their domain knowledge is embedded in the modeling tool, and thus made available to the whole development team. For more information about how this can be done, please see Section 2.3 and ‘MetaEdit+ Workbench User’s Guide’.