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Path: utzoo!linus!philabs!cmcl2!seismo!mcvax!jaap
From: jaap@mcvax.UUCP (Jaap Akkerhuis)
Newsgroups: net.unix,net.unix-wizards
Subject: Re: NROFF Question
Message-ID: <783@mcvax.UUCP>
Date: Tue, 30-Jul-85 01:31:43 EDT
Article-I.D.: mcvax.783
Posted: Tue Jul 30 01:31:43 1985
Date-Received: Thu, 1-Aug-85 05:03:42 EDT
References: <707@rlgvax.UUCP>
Reply-To: jaap@mcvax.UUCP (Jaap Akkerhuis)
Organization: CWI, Amsterdam
Lines: 31
Xref: linus net.unix:4588 net.unix-wizards:11275
Summary: RTFM

In article <707@rlgvax.UUCP> jrc@rlgvax.UUCP (Jim Chapell) writes:
 > 
 > Re: nroff, how come
 > .sp 4/2+1
 > 
 > spaces 1 line whereas
 > .nr s 4/2+1
 > .sp \ns
 > 
 > spaces 3 lines?
 > 

The answer is of course in the Nroff/Troff reference manual (Page 9,
alinea 1.4 \fINumerical expressions\fP).
"In the present of default scaling, ..." etc.

The commands
	.nr s 4/2+1
	.sp \ns
should be read as:
	.sp (4u/2u+1u)*1v
giving a spacing of 3 lines (default scaling is `v'),
while
	.sp 4/2+1
specifies a spacing of 42 units, rounded to 40 units (==\n(.v)
as shown by
	.nr a 4v/2v+1v
	.nr b \na/\n(.v
	.ie \nb>1 .tm \na  units rounded to \nb lines of spacing
	.el .tm \na units rounded to a single line of spacing
	.ab "End of demonstration"