Re: [Rd] inject html code into Rd file

[Romain Francois]

Le 03/04/10 02:04, Duncan Murdoch a écrit :

On 02/04/2010 8:06 AM, Duncan Murdoch wrote:
On 02/04/2010 7:13 AM, Romain Francois wrote:
Le 02/04/10 13:07, Duncan Murdoch a écrit :
On 02/04/2010 6:17 AM, Romain Francois wrote:
Hello,

I'm trying to inject html code into an Rd file. For example :

\name{test}
\alias{test}
\title{test}
\description{
\if{html}{
\Sexpr[stage=render,results=text,echo=FALSE]{
"<b>hello</b>"
}
}
}

when this file is rendered, instead of having "hello" in bold, I get
<b>hello</b>, i.e. characters < and > are replaced with html entities
: &lt; and &gt;

Is there a way to turn this off ?
Yes, if you wrap it in \out{}. The example in the manual is

\if{latex}{\out{\alpha}}\ifelse{html}{\out{&alpha;}}{alpha}

Duncan Murdoch
yes, I saw that in WRE, I should have been more specific.


what if instead of a trivial string like "<b>hello</b>" the text is
to be computed by some function. For example:

print( xtable( iris), type = "html" )

I think this should do it:

\Sexpr[stage=render,results=rd,echo=FALSE]{
paste("\\out{", "<b>hello</b>, "}", sep="")}

but this stuff hasn't been tested much, so there might be problems...

One problem is that the backslashes need to be escaped twice, so you'd want

\Sexpr[stage=render,results=rd,echo=FALSE]{
paste("\\\\out{", "<b>hello</b>, "}", sep="")}

and you'd probably want it wrapped in \if or \ifelse so that it doesn't
show up in text or latex output:

\Sexpr[stage=render,results=rd,
echo=FALSE]{"\\\\if{html}{\\\\out{<b>hello</b>}}"}

Duncan Murdoch

Thanks.
This gives one way to include images in a Rd file with data uri, here is 
a proof of concept (that depends on openssl to do the base 64 encoding):

img <- function(){
        tf <- tempfile()
        tf.out <- tempfile()
        png( tf, width = 500, height = 500)
        plot( 1:100, rnorm(100), pch = 21, bg = "red", cex =2 )
        dev.off()
        system( sprintf( 'openssl base64 -in "%s" -out "%s" ', tf, tf.out ) )
        sprintf( '\\out{<img src="data:image/png;base64,%s" />}',
                paste( readLines( tf.out), collapse = "\n" ) )
}

and the Rd file:

\name{test}
\alias{test}
\title{test}
\description{
\if{html}{
\Sexpr[stage=render,results=rd,echo=FALSE]{
        source( "test.R" )
        img()
}
}
}



It might be interesting to have something like results=asis or something.

Romain

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Romain Francois
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http://romainfrancois.blog.free.fr
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