The World Wide Web is now the primary means for information interchange that is mainly represented in textual format. However programs that create and view these texts generally do not adequately support texts using non-Latin scripts, particularly right-to-left scripts.

Unicode as a universal character set solves encoding problems of multilingual texts. It provides abstract character codes but does not offer methods for rendering text on screen or paper. An abstract character such "ARABIC LETTER BEH" which has the U+0628 code value can have different visual representations (called shapes or glyphs) on screen or paper, depending on context. Different scripts which are part of Unicode can have different writing rules for rendering glyphs and also composite characters, ligatures, and other script-specific features.

In this paper we present a general approach to encoding script-specific writing rules based on the Unicode character set and using finite state automata. This approach will be demonstrated with writing rules for some languages that use the Arabic scripts.