[Rd] DESCRIPTION and PACKAGES files.

[Prof Brian Ripley]

On Thu, 20 Jul 2006, Allen S. Rout wrote:

> 
> Greetings; I'm working on translating the heirarchy of R packages into
> the Gentoo Ebuild environment, currently working from a 2.3.1 install.
> 
> There are several data which it would be nice to see provided
> alongside the existing output of available.packages; at the moment I
> think I'm going to have to get License and SystemRequirements out of
> individual package DESCRIPTIONs.
> 
> More generally, it'd be nice to see all the documented fields from
> DESCRIPTION files in the output from available.packages(), or at least
> collated in PACKAGES.
> 
> I have a suggestion to accomplish this which I've hacked up locally
> and am happy to build a patch if the suggestion is well-recieved.
> 
> available.packages uses read.dcf on the PACKAGES file, accepting only 
> 
> flds <- c("Package", "Version", "Priority", "Bundle", "Depends",
>   "Imports", "Suggests", "Contains")
> 
> 
> If we could optionally accept all of the fields which are mentioned in
> 'Creating R Extensions', someone who was interested in the broader
> data could get at it.
> 
> PACKAGES would grow, substantially, but wouldn't be harder to
> maintain; in fact PACKAGES could be just a naive concatenation of
> everyone's DESCRIPTION files.

And that is the reason: everyone who downloads pays the price for unneeded 
fields in that file.  It was a deliberate decision to minimize download 
times, which are already substantial for people on a dialup connection.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
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