[Rd] embed Sweave driver in .Rnw file

[Romain Francois]

Le 14/12/10 13:21, Friedrich Leisch a écrit :
>>>>>> On Tue, 14 Dec 2010 12:40:04 +0100,
>>>>>> Romain Francois (RF) wrote:
>
>    >  Hello,
>    >  Sweave lets you use alternative drivers through the driver argument, and
>    >  several packages take advantage of that and define custom Sweave driver
>    >  for various purposes. Most of them are listed on the Reproducible
>    >  Research CTV:
>    >  (http://cran.r-project.org/web/views/ReproducibleResearch.html)
>
>    >  The next natural step is for package developpers to take advantage of
>    >  this in their vignettes. In Rcpp we work around the way package building
>    >  works and we do:
>    >  - let R build a dummy vignette
>    >  - then use the inst/doc/Makefile to replace it with a vignette that is
>    >  processed by the driver from the highlight package (giving syntax
>    >  highlighting).
>
>    >  I played with Sweave so that it would be able to create the driver from
>    >  some text included in the text of the .Rnw file:
>
>    >  $ svn diff
>    >  Index: src/library/utils/R/Sweave.R
>    >  ===================================================================
>    >  --- src/library/utils/R/Sweave.R	(revision 53846)
>    >  +++ src/library/utils/R/Sweave.R	(working copy)
>    >  @@ -20,6 +20,16 @@
>    >    # We don't need srclines for code, but we do need it for text, and
>    >  it's easiest
>    >    # to just keep it for everything.
>
>    >  +SweaveGetDriver<- function(file){
>    >  +    txt<- readLines(file)
>    >  +    line<- grep( "\\SweaveDriver", txt, value = TRUE )
>    >  +    if( length(line) ){
>    >  +        txt<- sub( "^.*\\SweaveDriver[{](.*)[}]", "\\1", line[1L] )
>    >  +        driver<- try( eval( parse( text = txt ) ), silent = TRUE )
>    >  +        if( !inherits( driver, "try-error") ) driver
>    >  +    }
>    >  +}
>    >  +
>    >    Sweave<- function(file, driver=RweaveLatex(),
>    >                       syntax=getOption("SweaveSyntax"), ...)
>    >    {
>    >  @@ -28,7 +38,9 @@
>    >        else if(is.function(driver))
>    >            driver<- driver()
>
>    >  -
>    >  +    drv<- SweaveGetDriver(file)
>    >  +    if( !is.null(drv) ) driver<- drv
>    >  +
>    >        if(is.null(syntax))
>    >            syntax<- SweaveGetSyntax(file)
>    >        if(is.character(syntax))
>
>
>
>    >  This allows one to write something like this in their file:
>
>    >  %\SweaveDriver{ { require(highlight); HighlightWeaveLatex() } }
>
>    >  So that when calling :
>
>    >>  Sweave( "somefile.Rnw" )
>
>    >  the highlight driver is used instead of the default driver.
>
>    >  Could something like that be added to Sweave ?
>
> Yes, sure!
>
> Will have a look at the patch later this week and apply it if it
> passes the tests.

Great. Let me know if I can expand on it (documentation, etc ...)

> The patch is against a current r-devel?

yes. rev 53846.

> Best,
> Fritz



-- 
Romain Francois
Professional R Enthusiast
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
|- http://bit.ly/fT2rZM : highlight 0.2-5
|- http://bit.ly/gpCSpH : Evolution of Rcpp code size
`- http://bit.ly/hovakS : RcppGSL initial release