Degree Name

MS (Master of Science)


Computer and Information Science

Date of Award


Committee Chair or Co-Chairs

Phillip E. Pfeiffer IV

Committee Members

Martin L. Barrett, Christopher D. Wallace


Connotational subtyping is an approach to typing that allows an object's type to change dynamically, following changes to the object's internal state. This allows for a more precise representation of a problem domain with logical objects that have variable behavior. Two approaches to supporting connotational subtyping in the Ruby programming language were implemented: a language-level implementation using pure Ruby and a modification to the Ruby 1.8.7 interpreter. While neither implementation was wholly successful the language level implementation created complications with reflective language features like self and super and, while Ruby 1.8.7 has been obsoleted by Ruby 1.9 (YARV), the results suggest that Chambers-style, predicate-based runtime type inference could be incorporated into Ruby with only some reduced interpreter performance.

Document Type

Thesis - unrestricted


Copyright by the authors.