Rational and CelsiusTech Form Joint Venture in Sweden

Dateline: January 7, 1994

Rational and CelsiusTech Systems announced on December 16, 1993, that they have formed a joint venture to move its developers to Rational Apex, an integrated Ada software-engineering environment for open systems. The venture, which will become operational in January 1994, will be located in Sweden and will be staffed by experienced software engineers from both companies. Eventually, the company will branch out to offer turnkey software-engineering support solutions to medium- to large-scale organizations.

[Source: Rational News Release, December 15, 1993; for more information, contact Kara Myers 408/496-3891.]

          An Ada 9X Subset for Inheritance-Based Reuse 
                 and Its Translation to Ada 83 

Dateline: January 6, 1994

Paper presents an approach to an object-oriented reuse strategy that may be incorporated in a system under development before Ada 9X becomes viable. The reuse strategy is based on the Ada 9X inheritance syntax.

Defines a minimal Ada 9X subset that implements inheritance based reuse and outlines its translation to Ada 83. Inheritance allows software modules to be reused without modifying the original source.

Ada 83 does not support inheritance, but low-level reuse can still be implemented in the form of generic components. The cost advantage from low-level reuse is already assumed when today's software systems are planned. Further cost savings must come from high-level reuse, which needs inheritance to be implemented properly. Inheritance will be fully supported in Ada 9X.

[Source: Hirasuna, Michael, Westinghouse Electric Corporation, Ada Letters, January/February 1994, Vol 14, No. 1, pp. 50-60.

Compatibility Between Ada 83 and Ada 9X

Dateline: January 7, 1993

Ada 9X has been carefully designed to minimize incompatibilities with Ada 83 while meeting the overall goals of the requirements. According to the author, three incompatibilities are considered likely to occur in normal programs. They are:

New reserved words; Ada 9X has six new reserved words

Type Character has 256 positions in Ada 9X; in Ada 83, it had 128 positions.

Indefinite generic parameters; Ada 9X has distinct syntax for a generic formal parameters.

The author states that the following two potential incompatibilities are less likely to occur in normal programs:

Library package bodies; in Ada 9X, it is illegal to provide a body for a library package not requiring one.

Numeric_Error; in Ada 9X, this has been changed to a renaming of Constraint_Error.

The author explains how each of the above potential incompatibilities may be overcome.

[Source: Barnes, John, "Compatibility Between Ada 83 and Ada 9X," Ada User, Vol 14, No. 4, December 1993, pp. 158-160.]