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From: dmb@sei.cmu.edu (Daniel Berry)
Newsgroups: comp.text
Subject: Re: What features would you like in GNU troff?
Message-ID: <3817@fy.sei.cmu.edu>
Date: 14 Aug 89 13:16:06 GMT
References: <779@pcrat.UUCP> <355@wjh12.harvard.edu> <8388@killer.DALLAS.TX.US> <159@unmvax.unm.edu> <1989Aug3.193322.24941@algor2.uu.net> <9737@alice.UUCP>
Reply-To: dmb@sei.cmu.edu (Daniel Berry)
Distribution: comp
Organization: Software Engineering Institute, Pittsburgh, PA
Lines: 41

In article <9737@alice.UUCP> debra@alice.UUCP () writes:
>In article <1989Aug3.193322.24941@algor2.uu.net> jeffrey@algor2.UUCP (Jeffrey Kegler) writes:
>>In reflecting further on this, I feel that ability to produce dvi
>>files would be very valuable in GNU troff.  There are many drivers
>>available for these files, and such a facility would render GNU troff
>>usable under a much wider variety of circumstances.
>
>Also, most output drivers for Tex dvi format come for free whereas
>troff output drivers are mostly commercial. So the Tex dvi format would
>fit the GNU purpose much better.
>
>Paul.
>-- 
However, the original ditroff device independent format is FAR more
flexible. Besides the information stating which character goes where, there
are some additional semantic markers that are NOT present in dvi:
1. end of output line marker
2. end of input word marker
These two are extremely valuable for a number of ditroff postprocessors.
The first allows ditroff to be made tri-directional (L-R, R-L, and T-B)
for the purpose of multi-lingual formatting (Latin, Semitic, and Chinese)
with NO change to ditroff (In order to do same with TeX -- a la JTeX and
TeX/XeT, you have to change TeX).
The second allows an indexing program to find occurrences of original
words in an already formatted document. (See Abe-Berry article in SP&E
January 1989) 
There are many other uses that this information can be put to if you think
about it..
Therefore, I strongly suggest keeping the original functionality.

Yes, the ditroff drivers are mostly commercial, but they are not that
expensive (in the $400 range) and there are some public domain ones
available. This situation is NOT unlike that for DVI drivers..

Dan

-- 
Prof. Daniel M. Berry, Computer Science Department, Technion, Haifa 32000 ISRAEL
Tel:+972-4-294325, Bitnet:DBERRY@TECHSEL
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