The Ada 95 Booch Components

Overview

Please note that this web page is a work-in-progress. Some documentation, commentaries, statistics, source code, etc. will change over the course of time. If anything is updated on the Booch Components, you'll see it here first, so be sure to check from time to time.

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History

The Ada 95 Booch Components began in late 1994 when David Weller began a port of Grady Booch's C++ components.

A first beta release was soon available, followed by a release in February 1997.

In December of that year, David concluded that he wouldn't be able to continue with the Components and appealed on the Team Ada mailing list for a volunteer. Having already found the Components very useful, I got my employers' permission to take them on (not a speedy process); work began 18.vii.98.

Storage Management was added in August 1998 by Pat Rogers, thanks very much Pat! (you may like to visit Pat's web site).

License

The Components are issued under the GNU General Public Licence. The units that you need to instantiate and compile in order to use the Components in your own software are licenced under the "GNAT-modified GPL", which adds the following to the normal GPL permissions:

As a special exception, if other files instantiate generics from this unit, or you link this unit with other files to produce an executable, this unit does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU Public License.

Schedule

The current version has the following components available (the red parts, if any, are new since the last release):

See the Component Documentation for the details.

Tests, demonstrations and contributions

The Components are tested with GNAT. I try hard not to release anything that doesn't work with the latest public version.

I also use the Aonix ObjectAda compiler (the Special Edition; currently I am stuck at 7.2, because of some DLL hell which prevents 7.2.1 from working! I wouldn't regard a problem with OA as a very good reason for withholding a feature, though.

The Components come with test and demonstration code samples.

There is also a collection of contributions.

Issues

Please feel free to mail me with any thoughts you may have!

Lists; to use or not to use?
Many people, faced with the BCs for the first time, choose Lists (Single or Double) as their standard Container.

This is probably not the best choice. Lists are complex entities which, I suppose, would be useful if you were implementing a list-processing engine like Lisp.

You'll be a lot better off using Collections!

Hierarchy, Graphs and Trees
Most of the Components are derived from BC.Containers.Container (and are in packages that are children of BC.Containers). The only feature common at this level is iteration; implicit in the fact that BC.Containers is a generic package parameterised by the type Item is that Containers contain just one sort of thing.

This works fine except for Graphs; a Graph is a collection of Vertices (OK so far), while Vertices are connected by (not collections of) Arcs. Unless I can think of a sensible way of doing things, Graphs will remain outside the Containers hierarchy.

Although Trees come under the Container hierarchy, they aren't Containers. This is largely because of the difficulty of supporting standard Iterators in a non-linear structure like a Tree.

That said, I've tried to use a common style throughout.

Compilers
The new Aonix ObjectAda 7.2 demo compiler handles the stock Components without change, so the old "Aonix-only" versions of the test programs, which omitted Dynamic forms, are no longer needed.

The Components work well (for me) with GCC-3.2 and prerelease 3.3 compilers.

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