Polymorphic Type Inference for Object-Oriented Programming Languages

We present a type inference algoritm and its verification for an object-oriented programming language called O'SMALL. O'SMALL is a class-based language with imperative features. Classes are not first-class citizens. No type declarations are required. Type inference operates on an extended lambda-calculus into which O'SMALL is translated. The system features extensible record types, mu-types, and imperative types. This work belongs to both theoretical and practical computer science. In the theoretical part, the type inference algoritm for our lambda-calculus with records is formalized in order-sorted logic. In the practical part, the algoritm for let-polymorphism and imperative features is based on well-known approaches. These approaches are presented in a new fashion but they are not proven correct