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Doc. No.: X3J19/94-066
Date: 09/03/94
Project: Xbase Language
Type: Discussion paper
Author: François Ghoche
(The European Xbase Institute)

A Diagram for a Global Vision

by François Ghoche

A Diagram for a Global Vision

A Proposed global diagram for the Xbase standard project


First proposed in San Jose

During the San Jose meeting, I proposed to the members of the committee a quick diagram on the paper board. The purpose was :

  1. to propose a global view of where we are heading (one diagram is better than a thousand words);
  2. to put forward some general basis for leveling;
  3. to encourage converging views, because people may sometime be using different words for the same things, or the same words for different things.

A tool for public relations

We must sell the standard to the market even before it is completed.

I firmly believe that we must be able to present to the public a clear and coherent view of where we are heading with Xbase.

Further, our position will be stronger if we have a majority agreement on the proposed scheme.

While not as important as putting forward change proposals for the core language working draft document, this global view diagram is a key element to demonstrate to the public that we have some long term goals. We are not just standardizing on the lowest common denominator between the three leading DOS Xbase products, rather, that this is a first step in our plan.

The originally proposed diagram

Here is the diagram as it was proposed in San Jose:
((diagram missing))

After having had the opportunity to discuss it with Xbase users in public presentations and discussions, and after further work on this diagram, I would like to propose a modified version.

Step by step for a global vision

One of the important targets of such a diagram is to illustrate the fact that this is an evolving process, and that the goal will be achieved in several steps rather than one.

The diagram has to enable such an incremental presentation.

I would like to propose as an exemple the following steps in the presentation:

Defining the Core

The first step is to standardize the Core Language.

Core language

Core: the intention is to represent the core language, which has been otherwise named as base core and other names. It is suggested to retain only « core » as a short name for the « Xbase Core Language ».

Up to now, the core is the common ground (intersection) between dBASE IV 2.0, FoxPro 2.5a and Clipper 5.2c, as have been defined in the vendors proposal in San Jose. This will evolve as amended by the committee through 2/3 majority votes.

Not to Break Code

The committe has demonstrated since its early days its willingness not to break exixting code to the extent that no contradictory constructs are encountered.

Historical core

Historical Core: This is composed mainly of Osolete Constructs, included in the first release of the standard for compatibility with existing applications. The external square representing Obsolete Constructs could be dropped alltogether from the diagram in a further release (as well as the File Format square).

The Traditional File Formats

Some members of the committee have expressed users concern that traditional data table format may remain unstandardized. If this project is carried out, a separate standard sould handle such a task. The goal being to propose standard specifications for local tables in standalone products. Compliance would be required only for products referring specifically to standard Xbase data tables.

Files format module

File Formats: Represents the potential separate standard project, yet to be defined.

State of the Art

Evolving the Core standard into a set of standards for state of the art products and platforms requires further steps:

  1. strenghten and extend the Core with appropriate constructs;
  2. define appropriate language construcs to support graphical user interface features;
  3. standardize on an object oriented model and related language constructs;
  4. establish specifications for local set -related query constructs as well as rules for embedded SQL use in Xbase.

Extending the core

Extended core: This category appears to be necessary to cover such extentions to the language which extend functionalities and are not desired to be in the basic Core. Conformance rules can determine compliance to Extended Core as a different level. This could be equivalent to a "level II", but avoiding the trap of numbering levels.

Object Orientation, Graphical User Interfaces, and SQL, are the other subprojects identified by committee's vote in San Rafael.

Evolution of the standard

At the time determined as appropriate by the committee, parts of this scheme can be considered as obsolete, while others may be added.

Evolution and cleanup

Open Systems Extensions: This is an exemple of a yet to be defined category, which purpose would be to render Xbase effectively non-platform dependant, as well as compliant with Open Systems schemes. This is just an exemple of possible future extensions of the diagram.

The Future Goal

The diagram could evolve in the following way in future releases of the standard :

Adapting a standard to evolving market and environment is the appropriate way to keep it alive. This illustrates the potential dynamics of the Xbase project.

Future vision

Multimedia and Communications are shown here as exemples of possible extensions in future releases of the standard.

Nota Bene: You will notice that Cultural elements are not described as a separate component or subproject. This is because we consider they will be part of Core and Extended Core.


I believe the members of the committee should be encouraged to use such a framework and diagrams - or other means they consider more appropriate - for educational and public relation purposes. Magazines, users groups and marketing vectors may then take over the message with lesser chances that it be distorted in the process.


If the members of the committee think it is appropriate, I propose including Chapter 2 of this document as a rationale including such diagrams in an informative (non-normative) annex of the Working draft.


The diagrams are copyrighted material. Permission is given to use them by members of the committee outside the work of X3J19, as long as the author name (François Ghoche ATON & TEXI) is acknowledged.

Of course, this condition is void if the diagrams are included in the dpANS, as copyright is then transfered to X3/ANSI and usage falls in the public domain.

Members are free to modify the diagrams to express their personal vision of the subject. However, they are required in that case to mention the changes made.

Francois Ghoche -- 09 March 1994

Possible choices / Choix possibles :

* (© copyright 1992-1996, François Ghoche)

fg - dernière MàJ/last update: 19 Feb 96