[R] table of contents link style in R's PDF docs

[Duncan Murdoch]

On 26/09/2013 10:33 AM, Duncan Murdoch wrote:
> On 25/09/2013 11:38 PM, Ben Harrison wrote:
> > Hello,
> > I am mildly annoyed each time I use a PDF doc of an R package that the
> > table of contents hyperlinks are *only* on the page numbers. To activate
> > a hyperlink, one must carefully scan sideways from the text item wanted
> > to the far right of the page and click on a tiny box. Multiply that mild
> > annoyance by the large number of times I need to look up package help
> > docs, and I find myself here writing this message.
> >
> >   From my understanding (albeit poor), all of the R docs for packages are
> > to be written in Rd format. From that they are converted by the
> > functions in the tools package as required (to latex and PDF, or HTML,
> > etc). So the only thing that controls in the PDF docs the hyperlinks one
> > way or another is the latex style file used - in this case I believe it
> > is Rd.sty (/usr/share/R/share/texmf/tex/latex/Rd.sty on my system).
> >
> > Line 303 of that file contains the single setting of the \hypersetup{}
> > command for whether or not the text in the table of contents is
> > hyperlinked, or the page number:
> >
> >       linktocpage,%
> >
> > which causes it to implicitly be set to True. Setting it to false (or
> > just commenting out that line I suppose as false is the default) would
> > mean the *text* in the TOC is hyperlinked.
> >
> > So, is the desired behaviour intended to be that only the page numbers
> > are hyperlinked (and therefore to annoy me), or has no-one really
> > bothered themselves with it that much, or something else?
>
> It's been the way it is for about 14 years, and I don't recall anyone
> else complaining, so I'd conclude it must have been set that way with
> you in mind.
>
> More seriously, I prefer having the page number clickable to having just
> the text clickable.  Having both would be fine for both of us. There's a
> partially documented option "linktoc=all" that does that; it was added
> to the hyperref package in 2008, so you can hardly blame R for not using
> it back in 1999.  The only problem I can see with using it now is that
> some users might not have a sufficiently up-to-date LaTeX installation
> to use it; if their hyperref package doesn't know about linktoc, they
> won't be able to build anything at all.
>
> >
> > Can I recreate all the documentation on my system after I make a change
> > to Rd.sty?
>
> Easiest would be to just do a rebuild of R, but you could also do the
> PDF manuals one at a time using
>
> R CMD Rd2pdf  <pkg>
>
> from the directory where the package is installed, or where its source
> lives.

I took a look at changing this, and decided against it:  we've had 
trouble with varying versions
of hyperref in the past.  However, anyone who wants to control the 
hyperlinking can follow
the instructions in the Installation and Administration file and create 
an Rd.cfg file (and put it on the Latex path, e.g. in 
R_HOME/share/texmf/tex/latex) to configure their own installation. 
Putting the line

\ifthenelse{\boolean{Rd at use@hyper}}{\hypersetup{linktoc=all}}{}

into that file works to give hyperlinks on both the text and page 
number, provided you have a compatible version of
hyperref.  (This will be described in newer versions of the manual.)

Duncan Murdoch