Type Inferencing Based on Complete Type Specifications

Type specification completeness is a necessary prerequisite for support of object creating formulae in object calculus leading to formation of new types to be integrated into a type lattice containing the types from which they were formed. The paper shows what conditions should be satisfied in order that the inferred types could be correct and what is the systematic way of integration of these types into the existing type lattice on the basis of a well-defined subtype relation. Ignoring of the specification completeness for type inference may lead to inconsistent results. The paper contributes to clarification of type inferencing operations for the case of complete type specifications. 1 Introduction Abstract data type (ADT) concepts play more and more important role in data models and database systems. Introduced in database world in early 80s as a technique for inclusion of new user-defined types in relational DBMSs [16], ADT provides now a basis for object-oriented data models [10]..