GNU TeXmacs: a scientific editing platform http://www.texmacs.org

1Context, motivation, and objectives

GNU TeXmacs is a free wysiwyw (what you see is what you want) platform for editing scientific documents. Its development was initiated in the nineties by van der Hoeven and the latest version is available from http://www.texmacs.org. TeXmacs provides a unified and user friendly framework for editing structured documents with different types of content such as text, mathematics, computer algebra sessions, graphics, animations, hyperlinks, spreadsheets, etc. The rendering engine uses high-quality typesetting algorithms for the production of professionally looking documents, which can either be printed out or presented from a laptop. TeXmacs runs on all major Unix platforms, Mac OS X, and Windows.

Some parts of TeXmacs were originally inspired by TeX [4] and LaTeX [5]. However, contrary to other programs such as LyX [6] or Scientific WorkPlace [1], TeXmacs is not a graphical front-end for LaTeX, and an alternative rendering engine has been rewritten from scratch in C++. Besides an improved typesetting quality with respect to TeX, the rendering engine has the major advantage that documents are typeset in real time. This makes it possible to edit documents in a wysywig and user friendly way, without being distracted by compilation issues or encrypting formulas by LaTeX code.

Another objective of TeXmacs is to promote the development of free software for and by scientists, by significantly reducing the cost of producing documents, presentations, but also high quality user interfaces with other software. TeXmacs currently supports interfaces for many free computer algebra systems, such as FriCAS, Macaulay 2, Mathemagix, Maxima, Pari, Reduce, Sage, etc., for several other mathematical systems, such as Octave, Scilab, GNU R, Graphviz, TeXgraph, etc., and for certain versions of a few proprietary systems, such as Maple, Mathematica and MuPAD.

During the last years, TeXmacs has greatly evolved. Our current focus is on better portability to Mac OS X and Windows platforms and on making the user interface even more intuitive. In particular, the former X11 based graphical interface has recently been replaced by a modern looking interface relying on the Qt library, with platform dependent widgets and keyboard bindings. We are also working on better converters to other formats and more specific editing features for graphics, spreadsheets, presentations, etc.

Figure 1. Preparing a laptop presentation with TeXmacs.

= = = = = Figure 2. Computation of successive derivatives in a spreadsheet using Mathemagix.

2Some features of the editor

Efficiency for typing scientific documents.

TeXmacs has been designed for typing structured texts with mathematical formulas in an efficient and easy to learn way. For instance, mathematical symbols such as (\rightsquigarrow) can be typed using a natural keyboard shortcut ~>. There are also simple shortcuts for operating on the structure of the document, such as changing a theorem into a lemma.

Stylesheet language.

Extension language.

Laptop presentations.

Vector graphics editor.

Converters.

Semantic editing.

Mmx] use "graphix"; Mmx] $group ($width ("2ln", $graph (x :-> x * sin x)), $width ("2ln", $with ("dash-style", "10", $graph (x :-> x * cos x))))

Figure 3. Example of a Mathemagix session which draws the graphs of two functions. The resulting picture was further resized and annotated by the author from within the editor.

3Interfaces with computer algebra systems

We have already mentioned that TeXmacs can be interfaced to many external computer algebra systems and other software for scientific computations. Such external systems can be invoked in various ways:

1. The most classical communication is based on shell-like sessions, in which it is possible to evaluate commands and display the results in a nice, graphical way.

2. The external system can also be used as an aid for editing documents. For instance, one may use it to differentiate or simplify the current formula or the current selection.

3. A recent new feature (under development) is a spreadsheet facility, where any computer algebra system can in principle be used as a spreadsheet language (see Figure 2).

Particular efforts are currently being put into the development of a good interface for the Mathemagix computer algebra system [3], which is free software available from http://www.mathemagix.org. TeXmacs documents can be created and manipulated directly from Mathemagix, which makes possible to automate the creation of sophisticated pictures and animations. For example, in Figure 3, we produced the graphs of two functions with different attributes via the graphix package of Mathemagix. These graphs are in fact native graphical TeXmacs objects, so that they can be easily modified and annotated. In addition they are automatically redrawn whenever the size or the origin of the graph is modified by the user.

Bibliography