The specification of all aspects of a programming language requires adequate formal models and tool support. Montages specifications combine graphical and textual elements to yield language descriptions similar in structure, length, and complexity to those in common language manuals, but with a formal semantics. A broad range of people involved in programming language design and use may find it convenient to use Montages in combination with the tool GEM-MEX. It allows the automatic generation of high-quality documents, type-checkers, interpreters and symbolic debuggers.

In this paper we present an abstract mathematical model for the dynamic semantics of the Oberon programming language using the Evolving Algebras approach. Oberon is the object-oriented successor of Pascal and Modula2. The resulting formal specification is complete, compact, and understandable with minimal training.