                                 About Thot

Thot is a generic system for the development of document centered
applications based on the concept of structured active documents. It can be
used for building interactive system as well as automatic processors. It's
the result of many years of research at INRIA, CNRS and the University of
Grenoble (UJF), with a number of academic and industrial collaborations. The
Grif products, for instance, are a result of these collaborations.

The most significant contributions are acknowledged here.

Initial research

The earliest work at the origin of Thot is a joint research project launched
in 1983 by INRIA, CNRS and the University of Grenoble at the IMAG Institute.
At that time, producing documents with a computer was much more complex than
today. The most common tools were batch formatters which imposed a complex
process to their users. However, some of them, such as Scribe and later
LATEX, had a clean document model based on the logical structure of
documents that presented a number of interesting features. The project aimed
at exploring the problems to be solved to combine the advantages of these
formatters and those of interactive systems, hence the name of the project:
Grif (GRenoble Interactive Formatter).

During the first three years, the work was mainly carried on by a small team
leaded by Vincent Quint (INRIA) and Irne Vatton (CNRS, now at INRIA). Three
languages were defined for specifying respectively the logical structure of
documents, their presentation and their external syntax. An editor called
Grif was also built to implement these languages in a single interactive
editor-formatter.

Industrial collaborations

After publication of the first results [1], several collaborations started
with the industry and the academia.

In 1986, GSI Tecsi was the first software company that worked with the
research team. They used the Grif prototype for developing an ODA editor for
the PC. They also stimulated the research group to add missing features.
This cooperation was the opportunity to integrate a page model in the editor
and a PostScript output, to support WYSIWYG printing. Hassan Bedor, a PhD
student, was instrumental in this resarch.

Another project, called HYP, started in 1988, again with GSI-Tecsi, funded
by the French Ministry of Industry. The main objective was to combine a rich
hypertext functionality with structured editing. A large part of the
hypertext features [2] of the Grif editor come from this work.

Most of these extensions aimed at improving the original Grif
editor-formatter. Cooperation with SFGL opened a new perspective to the
structured approach to document editing. This company was interested in
using Grif as a user interface component for a software development
environment. This request helped the research team to consider a more
modular approach, where structured editing is a functionality added to a
broader software environment. This was also the opportunity for the research
team to extend Grif in the field of structured graphics.

In 1988, Gipsi, a start-up of INRIA, adapted the Grif editor to their X
terminals. They made improvements, specially to the user interface, to turn
it into an industrial product. They then decided to use it as the kernel of
a new SGML editor, as most of the concepts of SGML were already implemented.
The research team extended then the document model and the editor to make
them (almost) fully SGML compatible. The resulting software was called Grif
SGML Editor. This work was done (and funded) as part of ESF (Eureka Software
Factory) an Eureka project. In 1991, the group that developed the Grif
product at Gipsi founded a new company, called Grif SA, to develop and
market that technology.

In 1990, the joint research team from INRIA and IMAG counted 7 persons and
received the status of INRIA project with the name Opera. Structured
documents and related issues were the main topics of project Opera, but
other issues such as digital typography, hypertext and cooperative editing
were also part of the project charter. Among the new activities launched by
project Opera, one should mention the research of H. Richy on spelling
checking, as the checker she developed with E. Picheral [3] is now part of
Thot.

In 1991, the Euromath trust, which developed a working environment for
mathematicians using the Grif SGML Editor from Grif SA, asked project Opera
to study the issue of structure transformations in structured documents.
This work was funded by Euromath and accomplished by E. Akpotsui [4] as part
of his PhD. This is the origin of the work continued later by Ph. Claves and
more recently by S. Bonhomme and C. Roisin, who developed the structure
transformation mechanism for Amaya [5].

In 1993, project Opera contributed with Grif SA and O2 Technology in a
project funded by France Tlcom for studying the problems posed by
cooperative editing of structured documents stored in an object oriented
data base.

At the beginning of 1995, INRIA started a major joint project with
Dassault-Aviation in the area of concurrent engineering. Project Opera was
involved in addressing the issue of interactive structured documentation,
and took that opportunity to complete a task that started one year before:
the design of a new generation of structured editing tool, Thot. Thot is not
an editor, but a set of libraries that can be used for building applications
based on the concept of structured active documents [6].

The latest industrial collaboration of project Opera started in September
1996 with SGS-Thomson and is funded by the French Ministry of Industry. In
this project, Storia, Thot is used as a component of the Alliance
cooperative editor [7] that is experimented for improving cooperation
between remote sites.

Academic cooperations

All activities presented in the above section have been done in the context
of formal cooperations with industrial partners. Obviously, project Opera
had also a number of less formal contacts that had a strong influence on its
research activity. It is difficult to mention all people and organizations
that deserve some acknowledgement but we hope that the most influential are
listed below.

First of all, the following members of project Opera should be cited, as
they have strongly contributed to the development of Grif and Thot: J.
Andr, S. Bonhomme, D. Decouchant, N. Layada, V. Quint, H. Richy, C.
Roisin, I. Vatton.

As most of the research that led to Thot has been done in a joint team from
IMAG and INRIA, many people of these institutes should also be mentioned,
but the joint research team Bull-IMAG deserves a special mention, as many
collaborations have been done with them, through a number of student
projects and PhD theses where Grif and Thot were involved. These projects
helped a lot the Opera team to develop Thot and to specify and implement its
API and its application definition language (language A). Other IMAG or
INRIA projects were also very helpful in this respect, especially Spectre
(Ph. Schaar), Chloe (A.-M. Vercoustre) and Acacia (Ph. Martin).

Project Opera had a number of contacts abroad during its research on
structured documents and hypertext. In the early work on structured editing,
preparing a winter school and several publications [8] [9] with R. Furuta
(Texas A&M University) and J. Andr (INRIA-IRISA) was very helpful. Several
discussions and seminars prepared with G. Coray (EPFL), Ch. Vanoirbeek
(EPFL) and R. Ingold (Freiburg university) were also a way of refining our
approach, as well as contacts with M. Harrison and E. Munson (UC Berkeley).

Xerox (PARC and RXRC) should also be mentioned, as the Opera project had
many contacts with researchers in that company. In particular, experiments
for interchanging documents with Tioga helped a lot to improve the T
language.

From Thot to Amaya

Project Opera started its work with the Web by two simple experiments.
Language T was used to make a filter that generates an HTML form for Thot
documents. The HTML document model was also entered in Thot. After these
first steps, a prototype HTML editor/browser, called Tamaya was developed on
the basis of the Thot library.

This work was then continued in the context of project Wedi (Web EDItor),
funded by the European Commission (DG XIII), whose goal was to develop a
browser/editor for the Web. Tamaya was used as a workbench for experimenting
new ideas. Grif S.A. participated in the project with the mission of
building a commercial product, which is now known as Symposia.

While Symposia is based on the Grif SGML Editor, Tamaya was specifically
developed for HTML. It contains a parser that is flexible enough to cope
with most existing Web documents [10] and it implements a subset of the
Cascading Style Sheets (CSS). It was demonstrated at the 3rd and 4th WWW
conferences, and, at the beginning of 1996, W3C proposed to project Opera to
carry on the development of Tamaya within the Consortium.

Some people from INRIA then joined the W3C and, with other W3C staff
members, defined the specifications for the new Web client derived from
Tamaya. A new name was chosen, Amaya, and a new user interface was designed
that should make the editor as user friendly as a word processor, while
keeping its structured representation of documents.

The first beta version of Amaya was released to W3C members in July 1996 and
to the public one month later. The source code is available since January
1997.

The first version of Amaya does not take advantage of all features available
in the Thot library, on which it is based, but as Amaya is essentially
considered as an open-ended platform for experimenting new web features,
this rich set of editing and formatting functions is an advantage for
further developments.

References

[1] V. Quint, I. Vatton, ``Grif: an Interactive System for Structured
Document Manipulation'', Text Processing and Document Manipulation,
Proceedings of the International Conference, J. C. van Vliet, ed., pp.
200-213, Cambridge University Press, 1986.

[2] V. Quint, I. Vatton, ``Combining Hypertext and Structured Documents in
Grif'', Proceedings of ECHT'92, D. Lucarella, ed., pp. 23-32, ACM Press,
Milan, December 1992.

[3] H. Richy, P. Frison, E. Picheral, ``Multilingual String-to-String
Correction in Grif, a Structured Editor'', Proceedings of Electronic
Publishing 1992, EP92, C. Vanoirbeek et G. Coray, ed., pp. 183-198,
Cambridge University Press, April 1992.

[4] E. Akpotsui, V. Quint, ``Type Transformation in Structured Editing
Systems'', Proceedings of Electronic Publishing 1992, EP92, C. Vanoirbeek et
G. Coray, ed., pp. 27-41, Cambridge University Press, April 1992.

[5] S. Bonhomme, C. Roisin, ``Interactively Restructuring HTML Documents'',
Proceedings of the Fifth International World Wide Web Conference, Computer
Network and ISDN Systems, vol. 28, num. 7-11, pp. 1075-1084, May 1996.

[6] V. Quint, I. Vatton, ``Making Structured Documents Active'', Electronic
Publishing - Origination, Dissemination and Design, vol. 7, num. 2, pp.
55-74, June 1994.

[7] D. Decouchant, V. Quint, M. Romero Salcedo, ``Structured and Distributed
Cooperative Editing in a Large Scale Network'', Groupware and Authoring, R.
Rada, ed., pp. 265-295 (chap. 13), Academic Press, May 1996.

[8] J. Andr, R. Furuta, and V. Quint, Structured Documents, Cambridge
University Press, 1989.

[9] R. Furuta, V. Quint, J. Andr, ``Interactively Editing Structured
Documents'', Electronic Publishing -- Origination, Dissemination and Design,
vol. 1, num. 1, pp. 19-44, April 1988.

[10] V. Quint, C. Roisin, I. Vatton, ``A Structured Authoring Environment
for the World-Wide Web'', Proceedings of the Third International World-Wide
Web Conference, Computer Networks and ISDN Systems, vol. 27, num. 6, pp.
831-840, April 1995.
