GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
SILGraphite (formerly OpenGraphite) is a project within SIL's Non-Roman Script Initiative and Language Software Development groups to provide extensible cross-platform rendering capabilities for complex non-Roman writing systems. It consists of a rule-based programming language, Graphite Description Language (GDL), that can be used to describe the behavior of a writing system, a compiler for that language, and a rendering engine that can serve as the backend of a text processing application. SILGraphite renders TrueType fonts that have been extended by means of compiling a GDL program. It is currently being integrated into Gecko/Mozilla through the SILA project, a GNU/Linux port is also underway, and there are plans for OpenOffice.org and Abiword integration.