R help - Sep 2006 - Automatical download of needed packages from CRAN

I write a package foo which requires a package bar (from CRAN) to work. So in
the DESCRIPTION file I write Depends: bar. I would like it to be so that when
one installs foo, then it is automatically checked whether bar is installed, and
if not then bar is also installed at the same time. I remember having seen
packages which do so, but I can not figure out the mechanism
'Depends: bar' in the DESCRIPTION file does not solve the problem. Can
anyone help?
 
A related question: How to check programmatically that a specific package is
loaded?
 
Best regards
Søren

	[[alternative HTML version deleted]]

install.packages("foo", dep="Depends")

See online help. I think that the GUI version of install.packages
automatically does that.

Antonio.

2006/9/29, S?ren H?jsgaard <Soren.Hojsgaard a
agrsci.dk>:
> I write a package foo which requires a package bar (from CRAN) to work. So
in the DESCRIPTION file I write Depends: bar. I would like it to be so that when
one installs foo, then it is automatically checked whether bar is installed, and
if not then bar is also installed at the same time. I remember having seen
packages which do so, but I can not figure out the mechanism
> 'Depends: bar' in the DESCRIPTION file does not solve the problem.
Can anyone help?
>
> A related question: How to check programmatically that a specific package
is loaded?
>
> Best regards
> S?ren
>
>         [[alternative HTML version deleted]]
>
>
>
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>
>

On Fri, 29 Sep 2006, S?ren H?jsgaard wrote:
> I write a package foo which requires a package bar (from CRAN) to work. 
> So in the DESCRIPTION file I write Depends: bar. I would like it to be 
> so that when one installs foo, then it is automatically checked whether 
> bar is installed, and if not then bar is also installed at the same 
> time. I remember having seen packages which do so, but I can not figure 
> out the mechanism 'Depends: bar' in the DESCRIPTION file does not
solve
> the problem. Can anyone help?
It does if you use install.packages(dependencies=TRUE), the default from 
the Windows GUI menu.
> A related question: How to check programmatically that a specific 
> package is loaded?
Via search(): there are lots of examples in the R help files.  ?termplot 
is one.
>
> Best regards
> S?ren
>
> 	[[alternative HTML version deleted]]
>
>
-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
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