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From: em@dce.ie (Eamonn McManus)
Newsgroups: comp.text.tex
Subject: Re: TeX preprocessor?
Message-ID: <cccp@dce.ie>
Date: 3 Apr 91 17:01:42 GMT
References: <1991Mar30.215707.649@basho.uucp>
Organization: Datacode Communications Ltd, Dublin, Ireland
Lines: 20

john@basho.uucp (John Lacey) writes:
>Is there any way to write a TeX file that will process another TeX file 
>and reduce it to primitives and then write it out?  I'm thinking of 
>something extremely analogous to the C preprocessor.
>
>If that isn't possible, how hard would altering the structure of TeX to 
>conform more closely to that of cc, with separate passed being separate 
>executables. Or perhaps switches controlling those passes could be added.

Since the expansion of macros can depend intimately on the results of
TeX's typesetting (for instance, they may be invoked from \output when a
page is finished, or they may test to see whether the width of a box is
greater than some value), it is not possible to do this without
effectively doing everything that TeX would do anyway.  Given the
interesting possibilities introduced by conditional expansion and
recursion, I think it would be very hard to do even if
typesetting-dependent macros were ignored.

,
Eamonn