F-Bounded Polymorphism for Object-Oriented Programming

Bounded quantification was introduced by Cardelli and Wegner as a means of typing functions that operate uniformly over all subtypes of a given type. They defined a simple “object” model and used bounded quantification to type-check functions that make sense on all objects having a specified set of “attributes.” A more realistic presentation of object-oriented languages would allow objects that are elements of recursively-defined types. In this context, bounded quantification no longer serves its intended purpose. It is easy to find functions that makes sense on all objects having a specified set of methods, but which cannot be typed in the Cardelli-Wegner system. To provide a basis for typed polymorphic functions in object-oriented languages, we introduce F-bounded quantification. Some applications of F-bounded quantification are presented and semantic issues are discussed. Although our original motivation was to type polymorphic functions over objects, F-bounded qu...

• Type: Conference
• Year: 1989
• Where: FPCA
• Authors: Peter S. Canning, William R. Cook, Walter L. Hill, Walter G. Olthoff, John C. Mitchell
• Keywords: F-bounded Quantification, FPCA 1989, Object-oriented Languages, Polymorphic Functions, Programming Languages