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Using the lazy data mechanism

2 messages · John Fox, Brian Ripley

Original
John Fox
# 
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?

My system info:

----- snip -----

Version:
 platform = i386-pc-mingw32
 arch = i386
 os = mingw32
 system = i386, mingw32
 status = 
 major = 2
 minor = 2.1
 year = 2005
 month = 12
 day = 20
 svn rev = 36812
 language = R

Windows XP Professional (build 2600) Service Pack 2.0

Locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United
States.1252;LC_MONETARY=English_United
States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

Search Path:
 .GlobalEnv, package:MASS, package:car, package:methods, package:stats,
package:graphics, package:grDevices, package:utils, package:datasets,
package:svIO, package:R2HTML, package:svMisc, package:svSocket,
package:svIDE, package:tcltk, Autoloads, package:base

----- snip -----

Thanks,
 John

--------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox
Brian Ripley
# 
John,

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?

Brian
On Sat, 4 Feb 2006, John Fox wrote:

            

      
      
      
    

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

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