It walks you through the process of
1) designing a dsl with xtext
2) adding constraints
3) enhancing the generated text editor
4) generating some code out of it
in great detail (about 30) and very well written.
The author comes to this nice conclusion :
Finally, consider the effort we had to invest. It took a couple of pages to describe the process, but when you count the actual lines of code we had to write and the number of clicks we had to perform, you may agree that this does not amount to anything worth worrying about. The framework kept most of the complexities away from us.:-)
It is the power of frameworks like oAW that let us leverage the potential of DSLs and related concepts into our daily projects.