GNU TeXmacs is a free scientific text editor, inspired by TeX and GNU
Emacs. The editor allows you to write structured documents via a
WYSIWYG (what-you-see-is-what-you-get) and user friendly interface. New
styles can be created by the user. The program implements high-quality
typesetting algorithms and TeX fonts, which help you to produce
professional looking documents.

The high typesetting quality still goes through for automatically
generated formulas, which makes TeXmacs suitable as an interface for
computer algebra systems. TeXmacs also supports the Guile/Scheme
extension language, so that you may customize the interface and write
your own extensions to the editor.