TOWARDS A PROGRAMMING LANGUAGE ONTOLOGY

We examine the role of semantic theory in determining the ontology of programming languages. We explore how different semantic perspectives result in different ontologies. In particular, we compare the ontological implications of set-theoretic versus type-theoretic semantics. 1 Programming Languages Programming languages (PLs) combine two, not always distinct, facilities: data structures (e.g., numbers, lists, trees, finite sets, objects) and control structures (e.g., assignment, iteration, procedure calls, recursion) that operate on these data structures. Data and control structures come in all shapes and sizes [12], [10], [8]. In particular, they are immensely varied in their style of presentation and conceptual content. For example, logic based languages such as Prolog are based upon Horn clause logic with a very primitive type structure. Functional ones such as MirandaTM have no imperative features and use recursion equa-tions and inductive data types as their means of constructing programs. Imper