Path: utzoo!mnetor!uunet!oddjob!gargoyle!ihnp4!ihlpg!bamford
From: bamford@ihlpg.ATT.COM (Harold E. Bamford)
Newsgroups: comp.text
Subject: Re: nroff transparent mode
Message-ID: <4870@ihlpg.ATT.COM>
Date: 19 Feb 88 15:52:52 GMT
References: <2694@druhi.ATT.COM>
Reply-To: bamford@ihlpg.UUCP (Harold E. Bamford)
Distribution: comp
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 42
Keywords: 9700 Xerox

In article <2694@druhi.ATT.COM> holder@druhi.ATT.COM (HolderML) writes:
>I'm trying to send some escape sequences through nroff (the DWB 2.0 version
>running on System V.2 on Amdahl UTS) to generate some special characters
>and to do some highlighting (shading) on a Xerox 9700 printer.
>Nroff/Troff User's Manual indicates that to have text transparently copied
>to the output, I should use the \! at the beginning of the line.  However,
>it looks like nroff is not copying the text transparently.  For instance,
>when I give it the following input:
>
>	.DS
>	\!This is shaded text.
>
>	\!\033\033\017This is shaded text.\033\033\016
>	.DE

I think there may be two problems here:

1) The character sequence "\033" is recognized as the special character
   \0 followed by the two characters 33.  If you want an escape char,
   then you must use an escape char, not a 4-char sequence that we
   generally recognize as MEANING escape.  In this respect, nroff is not
   as smart as echo(1) or ed(1).

2) I recognize "<ESC><^O>" as being an escape sequence used by the
   xerox(1) or x9700(1) programs.  These programs format card images for
   the 9700 printer, but the card images don't actually contain the
   escape sequence.  Are you running the output of nroff through one
   of these filters?


Finally, you should be aware that the \! sequence appends a newline to
the literal string that you provide; the newline used to terminate the
literal string is also output.  If you are trying to output an escape
sequence to turn on some mode, and this mode is then reset by a newline,
you are doomed.  I would be happy to be proved wrong on this as it has 
proved to be a problem for me.

				Harold Bamford
-- 
				Harold Bamford, AT&T Bell Labs
				IHP 2F-524 (312) 416-7397
				ihnp4!ihlpg!bamford