Publication Date

8-1995

Technical Report Number

TR95-19

Subjects

Computer Systems Organization, Software

Abstract

Two major obstacles hindering the wider acceptance of multi-methods are concerns over the lack of encapsulation and modularity and the absence of static typechecking in existing multi-method-based languages. This paper addresses both of these problems. We present a polynomial-time static typechecking algorithm that checks the conformance, completeness, and consistency of a group of method implementations with respect to declared message signatures. This algorithm improves on previous algorithms by handling separate type and inheritance hierarchies, abstract classes, and graph-based method lookup semantics. We also present a module system that enables independently-developed code to be fully encapsulated and statically typechecked on a per- module basis. To guarantee that potential conflicts between independently-developed modules have been resolved, a simple well-formedness condition on the modules comprising a program is checked at link-time. The typechecking algorithm and module system are applicable to a range of multi-method-based languages, but the paper uses the Cecil language as a concrete example of how they can be applied.

Comments

Copyright © 1995 by the Association for Computing Machinery, Inc. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that new copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Publications Dept, ACM Inc., fax +1 (212) 869-0481, or〈permissions@acm.org〉. Appendix copyright© Craig Chambers and Gary T. Leavens, 1995.

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