You might have read (about) the book Domain-Specific Languages written by Martin Fowler. As the name suggests it is about these little useful programming languages you can built very easily with Xtext.
The Abstract Syntax Tree is the base framework for many powerful tools of the Eclipse IDE, including refactoring, Quick Fix and Quick Assist. The Abstract Syntax Tree maps plain Java source code in a tree form. This tree is more convenient and reliable to analyse and modify programmatically than text-based source. This article shows how you can use the Abstract Syntax Tree for your own applications.
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