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.

Montages are a new way of describing all aspects of programming languages formally. Such specifications are intelligible for a broad range of people involved in programming language design and use. In order to enhance readability we combine visual and textual elements to yield specifications similar in structure, length, and complexity to those in common language manuals, but with a formal semantics. The formal semantics is based on Gurevich's Abstract State Machines (formerly called Evolving Algebras).

We unify static and dynamic semantics through the use of Montages, a version of Evolving Algebras specially tailored for programming languages. Montages combines graphical and textual elements to yield specifications similar in structure, length, and complexity to those in common language manuals, but with a formal semantics. We aim at a formal instrument which can be equally good understood by language designers, compiler constructors, and programmers. T I CT := CT.NT endif if CT.Condition.Value then Apply(CT)(CT.Left.Value, CT.Right.Value) else CT.Value := if RelOp(CT) then endif endif CT := CT.NT CT := CT.TrueTask Right Left S2-Expr S1-Expr NT NT S-RelOp WhileStment ::= WHILE Expr RelOp Expr DO StmentSeq END NT S-DO NT if DO(CT) then Condition TrueTask S-StmentSeq condition CHECK BOOL EXPR 1 Introduction Our work introduces Montages as a method for defining programming language semantics using Evolving Algebras. EAs have been proposed by Y. Gurevich as a dynamic generaliza...

State Machines Philipp W. Kutter Applied Formal Methods Institute AG and Institute TIK, ETH Zurich June 5, 2002 1