TeX has originally been designed with European languages in mind, and thus, whenever a paragraph contains text portions running in opposite directions, e.g. when combining English and Arabic or Hebrew in the same document, the task of line-breaking becomes rather complicated.

For a clean solution, Knuth and MacKay have proposed an modification to TeX, TeX-XeT, which will produce an extended DVI file containing additional directional information to be exploited by a modified DVI driver; and by now there exist several implementations of this idea, including TeX-XeT that produces a standard DVI file. The main drawback is just that we have to go outside the TeX standard.

We present a portable technique to handle bidirectional line-breaking by using TeX macros alone, albeit at some sacrifice in quality. This technique has been implemented in the version 3.02 of the author's multi-lingual ArabTeX package.