It seems that many package authors do not proofread the help installed
with their packages. The Rd converter is not a parser, and it will
silently produce incorrect results on incorrect input (and some correct
input).
Here are a few hints about some common errors:
1) When you run R CMD check you get a PDF manual at
<pkg>.Rcheck/<pkg>-manual.pdf. Read through it looking for missing/empty
and mis-formatted entries.
2) Try installing the package under a current R-devel (as of today).
This will report on errors of the form
\item{foo} {item text}
with, NB, invalid space between the two arguments. Earlier versions of
R assume that the item had no text and so '{item text}' is never
processed (not even checked for validity). This results in at best
missing information and at worse nonsense.
3) Grep the installed help for internal constructs, e.g.
grep nornal-bracket <installed-package>/help/*
Three ways I have found such constructs to appear in the processed files:
a) If you see 'eqnnormal-bracket' then you have a one-argument \eqn (or
possibly \deqn) command immediately followed by }. This is correct Rd but
mis-processed in earlier versions of R. In all the cases I have seen it
comes from grammatically incorrect help files of the form
\item{foo}{... \eqn{x}}
where the item should end in ',' or '.'. But if you don't want to do
that, at least use a space before the brace. I found this in packages
distrMod, flexclust, geepack, geoR, psychometric, robustbase and uroot.
b) Many packages have help files with 'normal-bracket' at the end of a
processed \value section. In all the cases I looked at, this results from
using \itemize{} inside \value -- that does not work as \value is
implicitly an itemize environment.
c) Using markup in verbatim-like environments will lead to nonsensical
output: it seems the most common error is to use \code inside \examples.
What markup is allowed where is not very well defined: Duncan Murdoch has
started to document this at http://developer.r-project.org/parseRd.pdf but
that currently is more a description of what should happen, not what has
been implemented.
These issues are not rare (except 3a): about 10% of CRAN packages have
them.
--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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