[Rd] Linking to documentation from a vignette using markdown?

[Spencer Graves]

Hi, Duncan:


On 10/18/2015 8:18 PM, Duncan Murdoch wrote:
> On 18/10/2015 5:51 PM, Spencer Graves wrote:
>> Hello:
>>
>>
>>         What's the preferred way to link to package documentation from a
>> vignette using markdown?
>>
>>
>>         My current draft includes
>> "[cumsum](https://stat.ethz.ch/R-manual/R-devel/library/base/html/cumsum.html)"
>> to link to the help page for cusum{base} and
>> "[KFAS](https://rweb.crmda.ku.edu/cran/web/packages/KFAS/KFAS.pdf)" to
>> link to the pdf documentation for the KFAS package.  This works, but it
>> feels like an ugly hack, and I wonder if there might be some more
>> elegant way of doing this (documented in a fine manual I have yet to find)?
> You can include links that work only when R is displaying the help using
> relative URLs like
>
> ../../base/help/cumsum
>
> or
>
> ../../base/html/cumsum.html
>
> (The former is like doing ?cumsum, i.e. it uses the alias; the latter
> goes directly to a page by its name.)
>
> The advantage of this kind of link is it doesn't need an Internet
> connection, it works with the R help system; the disadvantage is that it
> only works when the help system is running, so those links won't work in
> the copy of your vignette on CRAN, for example.


       Thanks.  I think I saw links like these reading html trying to 
find what I needed for [KFAS];  this helps me understand what I read.  I 
think I'd prefer having links that work in a pdf that I could pass to 
someone who may not have R installed.


       What's the easiest way to find links like the absolute web 
address I gave for [KFAS]?  It took me a couple of hours, because I 
couldn't find how to get more than "https://rweb.crmda.ku.edu/cran/" 
from any of my current web browsers (Safari, Chrome, and SeaMonkey on OS 
X 10.11, Internet Explorer, Chrome, FireFox and SeaMonkey under Windows 7).


       Thanks again,
       Spencer
>
> Duncan Murdoch