Ada in Switzerland
15th Meeting -- 95/11/23


It is our pleasure to announce that Ada in Switzerland will hold its fifteenth meeting at the University of Bern, on November 23, 1995.

As usual, we have a program of high quality, with a combination of presentations which will bring you practical advice, reports of project experience, and insights on some innovative uses of the language.

Some of the presentations will deal with the newest mechanisms of Ada 95, today's most advanced standard programming language. Ada 95 is the first internationally standardized object-oriented programming language (since February 1995). Ada 95 compilers have already been validated in October and November of this year. Inexpensive Ada compilers for e.g. Windows are now available, and more will become available in the near future.

A small exhibition of Ada vendors, including Rational Software Corporation and Thomson Software Products, will allow current and potential users of Ada to examine the newest tools and environments.

Educators should note that most Ada vendors provide free or discounted versions of their compilers and tools to educational institutions; by attending our meeting you will see for yourself what kind of state-of- the-art, industrial-quality tools you could use to better train your students.

I look forward to meeting you in Bern.

-- Magnus Kempe
Chair, Ada in Switzerland

This announcement includes:


Ada in Switzerland
15th Meeting
November 23, 1995

Institut fuer Wirtschaftsinformatik
Room E8/001 (E8/002 for the exhibition)
University of Bern
Engehaldenstr. 8
3012 BERN		(within walking distance of the railway station)

  Follow the signs until you reach the main taxi-rank
  Turn left and follow this for about 200m (the pavement gets very narrow
  -- but don't worry) until you meet a major set of traffic lights.
  Cross at the lights and head left under the railway bridge.
  At the next set of traffic lights, cross again and then take the first
  right.  This is signposted "Engehalde" and is in fact Engehaldestrasse.
  The IWI building is behind the IAM building, on Engehaldenstrasse (both
  buildings are recent additions to the University of Bern).

Deadline for late registration:
  November 22, 1995.
Participation fee:
  CHF 10.- for members and students (others: see registration form).
Lunch fee:
  CHF 35.- (includes lunch, morning and afternoon breaks).

Payments to be made in cash at the entrance of the meeting.

Please feel free to forward this announcement to interested colleagues.


Final Program

 - Registration starts
 - Ada vendors exhibition opens

- Welcome
- Presentation of the Institute of Informatics at the University of Bern
  by Oscar Nierstrasz

- Chair message: Ada World News
  by Magnus Kempe

- Morning break
  Ada vendors exhibition

- Ada 95 as Implementation for Object-Oriented Designs
  by Stephane Barbey
  Software Engineering Lab., Computer Science Department, EPFL
  40 minutes + Q&A

- Astrophysical Modelling Using Ada:
  a new family of spectral line synthesis codes
  by M.J. Stift
  Institute for Astronomy, University of Vienna, Austria
  40 minutes + Q&A

- Lunch at the Mensa

- General Assembly and Elections

- Afternoon break
  Ada vendors exhibition

- Objectifying Relational Attributes for Ada
  by Earl Waldin
  Paranor AG
  40 minutes + Q&A

- Heterogeneous Data Structures and Cross-Classification of Objects with Ada 95
  by Magnus Kempe
  Software Engineering Lab., Computer Science Department, EPFL
  40 minutes + Q&A



General Assembly

Date: 23 November 1995, 13:40

Location: University of Bern


1.  Annual Report

2.  Finance and Budget

3.  Future Activities

4.  Elections

5.  Individual Propositions

The General Assembly will be held during the fifteenth meeting of
"Ada in Switzerland", after lunch.


Registration Form

I will participate in the 15th meeting of Ada in Switzerland,
on 23 November 1995 in Bern.








Date & Signature ........................................


  Lunch and coffee breaks           CHF 35.-

  Conference participation
    Members of Ada in Switzerland       free
    Students (with student ID)		free
    Members of SI only              CHF  20.- *
    Others                          CHF 100.- **
*/** Corresponds to annual membership fees, you may instead apply for

  Add CHF 10.- for registration later than November 12.
  Add CHF 20.- for registration at the door.

Payments will be collected at the entrance of the meeting room (except
for membership fees which will be billed after the conference).
Each participant will receive one copy of the proceedings.

Please send the registration form to the following address,
to arrive before November 22, 1995 (e-mail preferred):

	Magnus Kempe
	Chair, Ada in Switzerland
	CH--1015 Lausanne

	Fax: +41-21 693 5079

Email registrations will be confirmed.  Registration by phone is not accepted.



        Ada 95 as Implementation for Object-Oriented Designs

			   Stephane Barbey
			    DI-LGL / EPFL
	Software Engineering Lab., Computer Science Department
	  Swiss Federal Institute of Technology in Lausanne

In this paper, we show how Ada 95 can be used as an implementation
language for object-oriented designs. We present a strategy to map
Fusion class descriptions into Ada specifications, considering the
various kinds of qualifiers that can be applied to attributes, and
the various ways methods can be mapped. We also discuss issues
such as naming conventions, mapping of operations, use of mixins
and of generics. Finally, we show how bidirectional associations,
that usually end up in a mutual dependency, can be implemented in
Ada 95.


		 Astrophysical Modelling Using Ada: 
	    a new family of spectral line synthesis codes

			      M.J. Stift
			  University of Vienna

As in many other astronomical institutions, scientists at the
Institute for Astronomy of the University of Vienna, Austria, run
numerical codes that synthesise stellar spectra from appropriate
stellar atmospheric models and atomic data. Applications range
from the determination of stellar elemental abundances and of
macroscopic velocity fields (oscillatory or turbulent) to the
diagnosis of full Stokes profiles of selected atomic transitions
in magnetic stars in view of unveiling the magnetic geometry.
These applications are numerically very intensive. In sharp
contrast to all other relevant codes known to us the spectral line
synthesis codes presented here are written in DEC Ada running on
VAX and Alpha AXP processors under OpenVMS.

Four factors have led to the choice of Ada:
  a) dynamic allocation of array-slices, passive iterators and recursive
     invocation reduced the lines of code to a fraction and increased the
     readability of the code;
  b) operator-overloading in vector and matrix calculations increased
     abstraction, readability and reduced code size;
  c) The definition of Ada-packages representing abstract data types leads
     to a 'single-point-of-change' design.  A simple modification (followed
     by massive recompilation) and a new variation of the physical model can
     be examined; and
  d) the strict standards, the imminent release of Ada9X, the pledge of
     the DoD to support Ada for at least another 10 years, the increasing
     use of Ada in the space community and especially the report "Ada and
     C++: A Business Case Analysis" have encouraged us to choose Ada as
     our astrophysical programming language for the decades to come.


		Objectifying Relational Attributes for Ada

				Earl Waldin
				Paranor AG

A contributing factor to the "impedence mismatch" between
programming languages and relational databases is their different
concepts of type. Ada views a type as a set of values with
operations, whereas relational databases view a type as strictly a
set of values. Furthermore, current commercial relational database
systems provide only a small number of simple types.

This talk describes a CASE tool for bridging the two views of
types with a primary focus on types for relational attributes.
The tool uses object-oriented techniques for defining categories
and instances of types. These definitions are used to generate
implementations of types as well as database acccess code that
ensures type safety at the Ada-database interface.


		    Heterogeneous Data Structures
	  and Cross-Classification of Objects with Ada 95 

			    Magnus Kempe
			    DI-LGL / EPFL
	Software Engineering Lab., Computer Science Department
	  Swiss Federal Institute of Technology in Lausanne

The implementation of ADTs for homogeneous data structures has
become a classic example of ADT in Ada 83. With some effort, it was
also possible to implement a restricted form of heterogeneous
data structures, based on variant records. We show that various
approaches in implementing flexible heterogeneous data structures
with Ada 95 are now possible. One of these approaches is
generalized to create heterogeneous catalogues of cross-referenced
objects, thus implementing one kind of multiple classification.