2.1 Description

The free software GNU TEX

[vdH01,vdH02,Gro01] has been developed for several reasons:

The need for a general purpose and user friendly scientific text editor.
The need for high quality front-ends for computer algebra systems.
The need for free (in the sense of freedom) scientific software.

As its name indicates, the program was inspired by TeX/LaTeX for its typesetting quality and the possibility to write structured documents. The program was also inspired by GNU Emacs in the sense that it comes with an extension language, Guile Scheme, which allows the user to customize TEX

and even extend the editor. Nevertheless, TEX

is neither a TeX/LaTeX front-end, nor an extension of Emacs.

From the editing point of view, TEX has the advantage of being wysiwyg (what-you-see-is-what-you-get). This does not withstand the facts that TEX is also a structured editor [vdH01] and that its typesetting quality is comparable to TeX. In fact, the user may control the degree of desired wysiwygness and the user may "feel" the structure of a document in other ways than through the explicit display of "source code". From the typesetting point of view, many algorithms were taken from TeX (hyphenation, line-breaking, spacing, etc.), as well as the fonts. At certain points, improvements were made, especially with regard to typesetting automatically generated formulas.

GNU TEX can currently be used as an interface for many computer algebra systems and other scientific software: Axiom, Giac, GNUplot, Graphviz, Gtybalt, Macaulay2, Maxima, Mupad, GNU Octave, Pari, Qcl, GNU R, Reduce, Scilab and Yacas. Communication takes place using pipes or dynamic libraries and existing pretty printers for LaTeX can be reused in order to build an interface with a new system in a few hours. At a second stage, a working interface can be extended to allow for two-dimensional mathematical input, tab-completion, contextual menus, customized keyboard modes, and much more.

Being part of the GNU project, one of the main aims of TEX is to encourage the development of free computer algebra systems, by removing the burden of writing good user interfaces from the programmers. We believe that free programs in the sense of

http://www.gnu.org/philosophy/free-sw.html

are particularly important in science: which mathematician would accept a proof of a theorem contained in a black box, for which you do not have the legal right to open it? What is the scientific interest of a theorem which cannot be used in proofs of other theorems?

The TEX program is currently well suited for writing scientific articles and as an interface to the computer algebra systems mentioned above. Currently, we are working on better conversions with TeX/LaTeX and input/output filters for HTML/MathML. In the future, we plan to include a "universal spreadsheet", a technical drawing editor, and more structured editing facilities. This will provide end-users with an office suite for structured documents with a high degree of interaction with scientific applications. It also provides developers with a scientific editing platform.