[R] R package building

[Jay Emerson]

I agree with others that the packaging system is generally easy to
use, and between the "Writing R Extensions" documentation and other
scattered sources (including these lists) there shouldn't be many
obstacles.  Using "package.skeleton()" is a great way to get started:
I'd recommend just having one data object and one new function in the
session for starters.  You can build up from there.

I've only ran into time-consuming walls on more advanced, obscure
issues.  For example: the "Suggests:" field in DESCRIPTION generated
quite some debate back in 2005, but until I found that thread in the
email lists I didn't understand the issue.  For completeness, I'll
round out this discussion, hoping I'm correct.  In essence, I think
the choice of the word "Suggests:" was intended for the package user,
not for the developer.  The user isn't required to have a suggested
package in order to load and use the desired package.  But the
developer is required (in the R CMD check) to have the suggested
package in order to avoid warnings or fails.  This does, actually,
make sense, because we assume a developer would want/need to check
features that involve the suggested package.  In a few isolated cases
(I think I had one of them), this caused a problem, where a desired
suggested package isn't distributed by CRAN on all platforms, so I
would risk getting into trouble with R CMD check on the platform
without the suggested package.  But this is pretty obscure, and the
issue was obviously well-debated in the past.  The addition of a line
or two about this in "Writing R Extensions" would be friendly (the
current content is correct and minimal sufficient I believe).  Maybe I
should draft this and submit it to the group.

Secondly, I would advice a newbie to the packaging system to avoid S4
at first.  Ultimately, I think it's pretty cool.  But, for example,
documentation on proper documentation (to handle the man pages
correctly) has puzzled me, and even though I can create a package with
S4 that passes R CMD check cleanly, I'm not convinced I've got it
quite right.  If someone has recently created more documentation or a
'white pages' on this, please do spread the word.

Thanks to all who have -- and continue -- to work on the system!

Jay

>Subject: [R] R package building
>
>In a few days I'll give a talk on R package development and my
>personal experience, at the 3rd Free / Libre / Open Source Software
>(FLOSS) Conference which will take place on May 27th & 28th 2008, in
>the National Technical University of Athens, in Greece.
>
>I would appreciate if you could share
>your thoughts with me; What are today's obstacles on R package
>building, according to your
>opinion and personal experience.
>
>Thanks,
>--
>Angelos I. Markos
>Scientific Associate, Dpt of Exact Sciences, TEI of Thessaloniki, GR
>"I'm not an outlier; I just haven't found my distribution yet"



-- 
John W. Emerson (Jay)
Assistant Professor of Statistics
Director of Graduate Studies
Department of Statistics
Yale University
http://www.stat.yale.edu/~jay