Jochen Seemann presented a session on Visual Studio for Software Architects Future Directions in Modeling Tools to about 2000 people at PDC today.  This presentation covered topics of Domain Specific Languages (DSL), Software Factories and Visual Languages.  All of which I am interested in for advancing the industrialization of software.

 

Jochen put into context what a DSL meant by comparing it to an electronics circuit diagram.  In the electronics domain, this circuit diagram has specific meaning, but outside of that domain, it has no meaning whatsoever.  Hence the term, domain specific.  Continuing with the circuit diagram analogy, the language that is used, such as resistors, capacitors, transistors, etc. is specific to that domain.  Hence the term DSL.

 

He also compared DSL to UML where his view was that UML is a broad language for Object Oriented software engineering.  Sure you can customize UML to a large degree, but the problem is trying to use UML to describe something specific enough for a particular domain.  For example, he used the analogy of using use cases (text based) to describe the layout of the auditorium we were in and giving a 50 page use case document to construction workers to build the auditorium.  Using natural language (i.e. English) has a major problem with semantics.  That is, every person could read the use cases, including the construction workers, to build the auditorium and come up with different meaning as to what the words meant and therefore a different auditorium build out.  Hence the problem of using a generalized (read: unified) tool to describe something very (domain) specific.  Of course, no construction worker is going to read a 50 page use case document, they are looking for a blueprint that visualizes specifically what the auditorium is going to look like as the building blueprint is really a domain specific language and is actually a visual language since the blueprint is likely a CAD drawing.

 

This is where DSL comes in. DSL is customizing modeling to the extreme.  Jochen walked through a demo of building a DSL Visual Designer in Visual Studio, which basically consist of three steps.  First you define the domain model, second you define the notation for that model and third map the visualization of the domain model via notation elements.  All of which goes into a large XML schema file.

 

It is an incredibly powerful construct as not only does Visual Studio come with a number of (DSL) modeling templates, but the ability to add third party partner ISV templates and your own templates that all run on the same platform. This makes the interchangeability and reusability with a library of visual designers a reality.  Something that the software industry has been waiting for a long time.

 

Further the ability to link different model aspects and viewpoints means that the ability to code generate complete solutions a reality.  If you are interested in advancing the industrialization of software, I can only suggest that you have a real close look at Microsofts modeling strategy and download the latest DSL tools with the new release available tomorrow.