[Rd] Using the lazy data mechanism

Prof Brian Ripley ripley at stats.ox.ac.uk
Sun Feb 5 09:23:39 CET 2006


There are lots of examples without a namespace on CRAN.  The first in the 
alphabet (in the C locale) is DAAG.  Another example (but handled 
specially) is package 'datasets'.

Taking the version on CRAN (car_1.0-18) and adding

LazyData: yes
LazyLoad: yes

worked for me (and you don't actually need the second, as it works whether 
or not the R code is lazy-loaded).

Perhaps you can let me know offline what the problems are?


On Sat, 4 Feb 2006, John Fox wrote:

> Dear list members,
> I'm trying to use the lazy data mechanism with the car package, so far
> without success. The data sets are in the source package's data subdirectory
> in the form of compressed .rda files, and I added the directive LazyData:
> yes to the package's DESCRIPTION file.
> I suspect that the problem is that the package has no namespace, but I've
> been unable to find a reference in the Writing R Extensions manual (nor
> elsewhere) that suggests that this is necessary. Is there a place that I've
> missed that describes the lazy data mechanism?

There's are article in R-news, but that describes the mechanism per se. 
How to use it is in `Writing R Extensions'.


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

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