T E X Forever!

This paper explores new ways of doing input to and output from TEX. These new ways bypass our current habits, and provide fresh opportunities. Usually, TEX is run as a batch program. But when run as a daemon, TEX can be part of an interactive program. Daemons often that run forever, or at least for a long time. Hence the title of this paper. Usually, parsing and transformation of the input data is done by TEX macros, with little outside help. Often, this results in input documents that only TEX can understand. Also, TEX macros can be hard to write. We demonstrate the replacement of TEX macros by an external program. This is done in real time. Usually, TEX’s principal output is a dvi representation of typeset pages, for processing by a printer driver. However, TEX’s log file or console can be used to allow TEX to output the boxes it holds internally. (Alternatively, an extension of TEX could write this data out in a binary form.) Shipping out boxes rather than dvi allows an external program to do the page makeup. Don Knuth’s original conception was that TEX would be “just a typesetting language”. In some sense he “put in many of TEX’s programming features only after kicking and screaming”. The developments described above reduce our dependence on TEX macros, and so bring our use of TEX closer to Knuth’s original conception. Doing this will greatly improve its usefulness. Long live TEX!