[Rd] require vs library

[ripley@stats.ox.ac.uk]

On Sat, 22 Feb 2003, kjetil brinchmann halvorsen wrote:

> On this theme, I have another question. I have a package
> which needs another package (SuppDists) for only one 
> function. I do require() within that function only. Is that OK, 
> or should it be done within .First.lib ?

Yes, that's fine.  I should have stressed *at the top level* below.
In one scenario we have been experimenting with the objects in a package
are dumped to a database, and then loading the package makes the objects
available as promises and no longer executes the original package code.
Another scenario is to install with --save.

> > Another point: please do not call code with side effects like require, 
> > library or options at the top level in foo/R/foo, but do so within 
> > .First.lib.  This becomes important if the code is dumped or put in a 
> > database.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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