[Rd] Rd parsing

[Duncan Murdoch]

On 05/05/2009 5:04 AM, robin hankin wrote:
> Hi Duncan
> 
> I asked this question to R-devel, and there was no reply, so I thought
> I'd ask you
> directly.  Any ideas?
> 
> best wishes
> 
> Robin
> 
> 
> 
> 
> I am having difficulty including a LaTeX formula in an Rd
> file.
> 
> The example given in section 2.7 in 'Parsing Rd files' is:
> 
> 
>     \deqn{ f(x) = \left\{
>       \begin{array}{ll}
>       0 & x<0 \\
>       1 & x\ge 0
>       \end{array}
>       \right. }{non latex}
> 
> 
> For me, this gives:
> 
> \deqn{ f(x) = \left\{
> \begin{array}{ll}
> 0 \& x<0 \bsl{}
> 1 \& x\ge 0
> \end{array}
> \right. }{}
> 
> in the tex file, which is not  desired because the ampersand
> is escaped; the '&' symbol appears in the dvi file, and I
> want an ampersand  to indicate  alignment.
> 
> Also, the '\\' appears as \bsl{}, which is undesired; the
>  resulting dvi file (made by R CMD Rd2dvi) looks wrong.
> 
> How do I write the Rd file so as to produce non-escaped
> ampersands?

I think the way the docs show it should work but there's a bug in the 
conversion.  If you use the new converter tools::Rd2latex, it comes out 
as expected.  So there's a bug in the Perl version of Rdconv, presumably 
in share/perl/R/Rdconv.pm, and you might want to try to track it down 
and fix it if you know Perl well enough.  An alternative might be some 
kludge involving \input{}:  put the equation in its own file where 
Rdconv will ignore it.

I've cc'd R-devel on this again; maybe someone else can jump in with a 
better idea.

Duncan Murdoch