Systematic Removal of Nondeterminism for Code Generation in I O Automata

The Input Output I O automaton model developed by Lynch and Tuttle models components in asynchronous concurrent systems as labeled transition systems IOA is a precise language for de scribing I O automata and for stating their properties A toolset is being developed for IOA to support distributed software design and implemen tation One of the tools consists of a user assisted code generator from IOA into an imperative programming language such as C or Java One aspect that distinguishes IOA programs from programs written in imperative languages is the presence of nondeterminism which comes in the form of explicit nondeterministic statements and implicit schedul ing choices made during execution Code generation therefore consists partially of systematically removing all forms of nondeterminism In this paper we describe our approach and design for code generation We focus on the issue of removing implicit nondeterminism and spec ify a transformation on IOA programs that makes all nondeterminism explicit The programmer can then replace all explicit nondeterminism with deterministic statements prior to code generation We also describe this transformation at a semantic level i e at the level of the I O au tomaton mathematical model We show that the transformation de ned at the IOA level conforms to the one at the semantic level