Currently, the VIATRA2 Documentation consists of the following documents:
For current Milestones (3.x), a completely new documentation has been established at the VIATRA2 Wiki.
It contains both the users guide and the most up-to-date documentation of the VIATRA2 transformation language.
You should start here.
The VIATRA2 Transformation Language Specification [obsolete]
The document describes the VIATRA2 Transformation Command Language in detail. A VIATRA2 transformation
consists of graph pattern definitions (Section 3) defined by precise formal semantics (Section 4), and
control structures (Section 5).
The language specification is archived in PDF format from here.
Users' Guide [obsolete]
The Users' Guide offered a description of the user interface (which is completely superseded by the wiki),
howtos for writing model importers and native functions, and a by-example section to get you started
with writing VIATRA transformations.
Archived in PDF from here.