Accession Number : ADA265548


Title :   A New Definition of the Subtype Relation


Corporate Author : CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE


Personal Author(s) : Liskov, Barbara ; Wing, Jeannette M


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a265548.pdf


Report Date : Apr 1993


Pagination or Media Count : 23


Abstract : The use of hierarchy is an important component of object-oriented design. Hierarchy allows the use of type families, in which higher level supertypes capture the behavior that all of their subtypes have in common. For this methodology to be effective, it is necessary to have a clear understanding of how subtypes and supertypes are related. This paper presents a new definition of the subtype relation that ensures that any property proved about supertype objects also holds for subtype objects. It also discusses the ramifications of the definition on the design of type families.


Descriptors :   *REASONING , *PROGRAMMING LANGUAGES , *SEMANTICS , COMPUTATIONS , STACKING , QUEUEING THEORY , SPECIFICATIONS


Subject Categories : Linguistics
      Computer Programming and Software


Distribution Statement : APPROVED FOR PUBLIC RELEASE