[Rd] How to ship R scripts with R packages ?

[Romain Francois]

On 09/02/2009 01:13 PM, Duncan Murdoch wrote:
>
> Romain Francois wrote:
>> Hello,
>>
>> (This is a remix of this previous thread:
>> https://stat.ethz.ch/pipermail/r-devel/2009-August/054264.html , but
>> with a concrete example)
>>
>> I am developing some packages that contain scripts (for Rscript) and
>> would like to know what is the best/recommended way to ship these
>> scripts.
>>
>> An example is the "ant" package (R capable version of apache ant, see
>> http://tr.im/xHLs). The package has a ant.R script in the exec
>> directory and here is how I use it :
>>
>> $ `Rscript -e "cat( system.file( 'exec', 'ant.R', package = 'ant' ) ) " `
>>
>> ... not so pretty. Meanwhile, "Writing R extensions" talks about the
>> exec directory, but it is not clear if I can use it this way or how.
>>
>
> I think exec is a reasonable place to put the script. If you don't want
> to type that long command above, why not put it in a small function in
> the package? E.g. define
>
> antR <- function() cat( system.file( 'exec', 'ant.R', package = 'ant' ) )
>
> then you can run it with
>
> Rscript -e "ant::antR()"
>
> Duncan Murdoch

Yes. I'd have to do a bit more work to call the script with parameters. 
Something like this perhaps:

antR <- function( run = FALSE){
	rscript    <- file.path( R.home(), "bin", "Rscript" )
	ant.script <- system.file( 'exec', 'ant.R', package = 'ant' )
	cmd <- sprintf( '"%s" "%s" %s',
		rscript, ant.script, paste( commandArgs( TRUE), collapse = " " )
	
	if( run ){
		system( cmd )
	} else {
		run
	}
}

...

I guess i am looking for a mechanism similar to the dispatch of CMD, but 
able to dispatch within exec directories of packages :

$ R CMD exec ant ant.R

or maybe a --package switch in Rscript:

$ Rscript --package ant ant.R

or a Rexec script similar to Rscript :

$ Rexec ant/ant.R

-- 
Romain Francois
Professional R Enthusiast
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http://romainfrancois.blog.free.fr
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