Multilingual Typesetting with Ω, a Case Study: Arabic

International audience In this paper we describe the internal structure of the Arabic script package for the Ω typesetting system, as well as the techniques and tools used for its development. This package allows typesetting using regular LaTeX styles, in all Arabic alphabet languages: Arabic, Berber, Farsi, Urdu, Pashto, Sindhi, Uighur, etc. We also give a description of the character codes added to Unicode, to obtain the Unicode++ encoding, used by the Ω system for typesetting purposes.