[Rd] Package "datasets" not exporting anything on a recent R-2.15.1-patched

[Prof Brian Ripley]

On 26/08/2012 17:25, Laurent Gautier wrote:
> Hi,
>
> I just stumbled on the following apparent oddity: the package "datasets"
> does not appear to export anything out of its namespace:
>
>  > ns_datasets <- getNamespace('datasets')
>  > getNamespaceExports(ns_datasets)
> character(0)
>
> Not the case with other packages (example here with "utils"):
>  > ns_utils <- getNamespace('utils')
>  > head(getNamespaceExports(ns_utils))
> [1] "?"            ".DollarNames" "adist"        "alarm" "apropos"
> [6] "aregexec"
>
> Is this a temporary glitch, or is there something new and specific to
> "datasets" ?

Not new, been so since R 2.14.0.

The package contains no R code: the only reason it has a namespace is 
that since 2.14.0 all packages must have one.

There are other data-only packages, but not in base R.

Lazy-loaded data has not been part of the namespace for a long time: 
they are directly in the package's environment.  The reason is the 
namespace scoping rules: if the package's datasets were in its 
namespace, they would be found before any other dataset of that name by 
the package's R functions.

-- 
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