[Rd] Rscript and default packages

[Simon Urbanek]

On Sep 3, 2009, at 13:52 , Romain Francois wrote:

> On 09/03/2009 05:23 PM, Duncan Murdoch wrote:
>>
>> On 03/09/2009 9:53 AM, Romain Francois wrote:
>>> Hi,
>>>
>>> Is is possible to embed inside an R script, the name of the default
>>> packages to be loaded when the script is invoked with Rscript.
>>>
>>> I know about the --default-packages argument, but I was wondering if
>>> there was a mechanism to embed this information within the script  
>>> itself
>>
>> I don't understand what you'd want here that you don't get with  
>> attach()
>> or require(). Why does it matter if they are default?
>>
>> Duncan Murdoch
>
> Sorry for being vague. I am more interested in not loading some  
> packages:
>
> $ time Rscript  -e "#"
>
> real	0m0.224s
> user	0m0.188s
> sys	0m0.032s
>
>
> $ time Rscript --default-packages="base" -e "#"
>
> real	0m0.067s
> user	0m0.033s
> sys	0m0.016s
>
>
> $ time r -e "#"
>
> real	0m0.039s
> user	0m0.032s
> sys	0m0.006s
>
> This is related to the "How to ship R scripts with R packages"  
> thread. I'd like for example to ship a script that I know only  
> requires the "base" package. How would I specify this from within  
> the script.
>

Well, what's wrong with:

#!/usr/bin/Rscript --default-packages=base

ginaz:sandbox$ time ./scr

real	0m0.045s
user	0m0.027s
sys	0m0.017s

.. as opposed to

#!/usr/bin/Rscript --default-packages=base

ginaz:sandbox$ time ./scr

real	0m0.201s
user	0m0.166s
sys	0m0.034s

Cheers,
Simon