Extending Moby with Inheritance-Based Subtyping

Classes play a dual role in mainstream statically-typed object-oriented languages, serving as both object generators and object types. In such languages, inheritance implies subtyping. In contrast, the theoretical language community has viewed this linkage as a mistake and has focused on subtyping relationships determined by the structure of object types, without regard to their underlying implementations. In this paper, we explore why inheritance-based subtyping relations are useful and we present an extension to the MOBY programming language that supports both inheritance-based and structural subtyping relations. In addition, we present a formal accounting of this extension.

• Type: Conference
• Year: 2000
• Where: ECOOP
• Authors: Kathleen Fisher, John H. Reppy
• Keywords: ECOOP 2000, Inheritance-based Subtyping Relations, Object Types, Programming Languages, Subtyping