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From: guy@sun.uucp (Guy Harris)
Newsgroups: net.text
Subject: Re: Change bars in TeX (using SCCS)
Message-ID: <4085@sun.uucp>
Date: Thu, 12-Jun-86 02:07:51 EDT
Article-I.D.: sun.4085
Posted: Thu Jun 12 02:07:51 1986
Date-Received: Fri, 13-Jun-86 03:17:13 EDT
References: <154@grpthry.UUCP> <3493@mnetor.UUCP>
Distribution: net
Organization: Sun Microsystems, Inc.
Lines: 42

> 	2) System V (R1 I think) has a utility called "diffmk":

R2, etc., as well.  It's a shell script, so it may be modifiable to produce
the appropriate TeX commands.

> 	3) Read the s. file and follow the "^AI", "^AD" and "^AE" directives, 
> 	   emitting mc's as you go.  The internal format of SCCS isn't all 
> 	   that hard to understand...

And is sort of documented in SCCSFILE(4 or 5, depending on what version of
UNIX you're running).

Note, of course, that SCCS doesn't understand that changing

	The long sobs of the violins of autumn
	wound my heart with a monotonous languor

to

	The long sobs
	of the violins of autumn
	would my heart
	with a monotonous languor

(assuming that TeX is filling this text) should not get change bars, while
changing it to

	The long sobs of the violins of autumn
	wound my heart with a monotonous ennui

should.  "diff" (which gives SCCS its marching orders, at least when it
comes to indicating what's been inserted and what's been deleted) has no
idea why lines changed, it merely knows that they've changed, and tells SCCS
so.  Be prepared either 1) to hand-tune the margin bar indications (".mc" in
"[nt]roff" has enough other problems that you have to do this anyway if you
want it to be correct) or 2) to have them act as guides, which will
sometimes falsely indicate that something has changed, rather than as
reliable indicators of change.
-- 
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com (or guy@sun.arpa)