R-alpha: Re: S-help -- Ultimate doc.== source : $SPLUS/cmd/help.tr & help.nr

Martin Maechler Martin Maechler <maechler@stat.math.ethz.ch>
Fri, 23 May 97 09:51:34 +0200

if you really want to find out  what things an  S help file can contain,
you must learn some  nroff/troff  [ maybe use 'groff', the GNU one ].

As always, ultimate documentation is == source.
The definition of the S help is in
the two files
where nr ^= nroff, i.e.  ASCII   output
      tr ^= troff  i.e.  printed output (e.g via Postscript conversion)

help.tr starts with

.\" @(#)help.tr.pre version 2.33 created 9/22/95
.\" @(#)Copyright (c), 1987, 1995 StatSci, Inc.  All rights reserved.
.\" This file defines the macros that S-PLUS help files use.  This file
.\" 	was modified by the S-PLUS SETUP script to tailor it to your system.

The most important  [nt]roff command  here is
.de AB
	which stands for 'define the  AB  macro'
	which will be referenced by


Further note:	

	S-plus uses a slightly different help file format than
	'vanilla S' from AT&T.

	E.g, they (StatSci) introduced the extra 
	.RA  for 'Required ARGUMENTS'
	.OA  for 'Optional Arguments'
	where Chambers et al. just use 'ARGUMENTS' which comes
	automatically before the first argument (with  .AG .... ) is set.
PPS:  S version 4 uses a COMPLETELY different system.
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