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From: mwang@watmath.UUCP (mwang)
Newsgroups: ont.events
Subject: UW Systems Seminar, Dr. Cargill on "A Debugger's Object-Oriented Architecture"
Message-ID: <14680@watmath.UUCP>
Date: Mon, 27-May-85 14:26:10 EDT
Article-I.D.: watmath.14680
Posted: Mon May 27 14:26:10 1985
Date-Received: Wed, 29-May-85 01:32:05 EDT
Expires: Fri, 7-Jun-85 00:00:00 EDT
Organization: U of Waterloo, Ontario
Lines: 40


DEPARTMENT OF COMPUTER SCIENCE
UNIVERSITY OF WATERLOO
SEMINAR ACTIVITIES

SYSTEMS SEMINAR

                    - Thursday, June 6, 1985.

Dr. T.A. Cargill of Bell Laboratories will speak on ``A
Debugger's Object-Oriented Architecture.''

TIME:                2:30 PM   (Please Note)

ROOM:              MC 3008

ABSTRACT

The  choice  of  an  object-oriented architecture for a
debugger  has  influenced  the  software's evolution in
unforeseen  ways  and resulted in a program whose func-
tion  exceeds the author's original goals.  The motiva-
tion  for object-oriented programming was to experiment
with  a browser-like graphics user interface; it worked
well.   The  first unforeseen benefit was in the symbol
table:  lazy  construction  of  a abstract syntax-based
tree  (built from the loader's flattened format) gave a
clean  interface to the remainder of the debugger, with
an  efficient  and robust implementation.  Next, though
the  intention was to treat only one process at a time,
the debugger was trivially modified to control multiple
processes  simultaneously.  Finally, it was extended to
control  an  arbitrary  set  of  processes spanning the
user's  loosely-coupled timesharing computer and bitmap
terminal,  running  different operating systems on dif-
ferent  processors.  The debugger is written in C++, an
extension  of  C with Simula-like classes.  Those parts
of the debugger that adapt to different target environ-
ments   employ  the  type  derivation  and  inheritance
mechanism of C++.