The LingML project is devoted to developing logical encodings of theoretical objects in linguistics in XML. These encodings can then be rendered with standard formatting tools (HTML, LaTeX, PDF, etc.) or be subject to further computational processing.
The idea is to liberate the linguist from the tedium of formatting, while at the same time, tying our linguistic diagrams and formalisms to clear testable claims.
A more in-depth explanation of the project and demos can be seen here.
Logical encodings are given in XML, a widely-used markup language, related to HTML and SGML. These encodings are defined using a DTD or "Document Type Definition" file. The encodings should express the logic necessary to understand the theoretical device at stake. It should not include irrelevant formatting information.
These encodings are rendered and processed using the XSL stylesheet language, a programming language used to convert XML documents into other document formats (or even into different XML documents).
If you would like to use these resources, you don't need to worry about how the XSL works. Simply download the relevant XSL stylesheets, and follow the instructions on the XSL instructions page for how to process your document. Each project also provides sample XML files so that you can see working examples of how the system operates.
If you are interested in participating in this project, by revising some of the demo resources below or by adding new resources for the bijillions of theories not yet represented, simply send me the resources or links and I will be elated to add them.