A. Black on Object-oriented types at Harvard

Date: Wed, 18 Dec 91 15:00:26 EST
To: colloquium, cs-faculty, cs-gradstudents, cs-research, cs-staff
Subject: CRCT Colloquium Series Presents

Everything you always wanted to know about types for 
Object-oriented Systems
(but were afraid to ask)

Andrew Black
DEC and Harvard University

Monday, January 6, 1992
4  PM
Aiken Computation Laboratory 101
(Tea at 3:30 pm Aiken Main Lobby)


This talk aims to make accessible to practitioners some of the 
fruits of recent theoretical work on classes, types, inheritance, 
type generators and the relationships between them.  Although the 
theoretical research community is still far from a consensus on 
many topics, on many others there has been a convergence of views 
and a deepening of understanding.

Sadly, much of the more theoretical work on objects, particularly 
that which relates to types, is accessible only to trained logicians.  
This is unfortunate, because programmers, language designers and 
compiler writers have much to gain from a deeper understanding of the 
tools of their trade; in particular, they need to know which problems 
are solved (to avoid solving them again) and which problems are not 
(so that they can be avoided).

Based on the speaker's experiences with the design, implementation 
and modeling of the Emerald programming language, this talk will 
attempt to shed light on issues like:

     *  what makes an object different from a value
     *  what types are, and why they are good for you
     *  what subtyping is, and why it isn't enough
     *  why contravariance isn't an unnatural act
     *  why inheritance is a relationship between programs, not between
     *  whether you should care that TYPE is not a type
     *  ``polymorphism polyglot'' and how to avoid it
     *  what is the type of NIL, and whether it has one.

Host: Professor Victor J. Milenkovic