[Rd] When to use LazyLoad, LazyData and ZipData?

Duncan Murdoch murdoch at stats.uwo.ca
Wed Nov 14 13:58:03 CET 2007


On 11/14/2007 7:01 AM, Bjørn-Helge Mevik wrote:
> Dear developeRs,
> 
> I've searched the documentation, FAQ, and mailing lists, but haven't
> found the answer(*) to the following:
> 
> When should one specify LazyLoad, LazyData, and ZipData?
> 
> And what is the default if they are left unspecified?
> 
> 
> (*)Except that
> 1) If the package you are writing uses the methods package, specify
> LazyLoad: yes, and
> 2) The optional ZipData field controls whether the automatic Windows
> build will zip up the data directory or no: set this to no if your
> package will not work with a zipped data directory.

I think that you shouldn't care about these things, and should accept 
the default for them unless one of those two pieces of advice applies to 
you.  Let the package install code decide on what values to use.

If you want to know the current defaults, look at the INSTALL script in 
R_HOME/bin, but don't expect them to stay the same as versions change. 
For example, lazy loading saves memory but may take extra time; the code 
chooses a tradeoff based on the amount of data involved, and the details 
of that choice could easily change.

Duncan Murdoch



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