A Co-contextual Type Checker for Featherweight Java

A Co-contextual Type Checker for Featherweight Java

Kuci, Edlira (Technische Universität Darmstadt)
Erdweg, S.T. (TU Delft Programming Languages)
Bračevac, Oliver (Technische Universität Darmstadt)
Bejleri, Andi (Technische Universität Darmstadt)
Mezini, Mira (Technische Universität Darmstadt)

Müller, Peter (editor)

2017

This paper addresses compositional and incremental type checking for object-oriented programming languages. Recent work achieved incremental type checking for structurally typed functional languages through co-contextual typing rules, a constraint-based formulation that removes any context dependency for expression typings. However, that work does not cover key features of object-oriented languages: Subtype polymorphism, nominal typing, and implementation inheritance. Type checkers encode these features in the form of class tables, an additional form of typing context inhibiting incrementalization. In the present work, we demonstrate that an appropriate co-contextual notion to class tables exists, paving the way to efficient incremental type checkers for object-oriented languages. This yields a novel formulation of Igarashi et al.'s Featherweight Java (FJ) type system, where we replace class tables by the dual concept of class table requirements and class table operations by dual operations on class table requirements. We prove the equivalence of FJ's type system and our co-contextual formulation. Based on our formulation, we implemented an incremental FJ type checker and compared its performance against javac on a number of realistic example programs.

type checking
co-contextual
constraints
class table
Featherweight Java

http://resolver.tudelft.nl/uuid:8d9bbccf-7be4-48bc-9758-17ba107a45f6

https://doi.org/10.4230/LIPIcs.ECOOP.2017.18

978-3-95977-035-4

31st European Conference on Object-Oriented Programming (ECOOP 2017)

ECOOP 2017, 2017-06-18 → 2017-06-23, Barcelona, Spain

Leibniz International Proceedings in Informatics (LIPIcs), 1868-8969, 74

Institutional Repository

conference paper

© 2017 Edlira Kuci, S.T. Erdweg, Oliver Bračevac, Andi Bejleri, Mira Mezini