[Rd] linking to package directories is NOT broken in R >= 2.10 beta

Thomas Petzoldt Thomas.Petzoldt at TU-Dresden.de
Mon Oct 19 09:57:47 CEST 2009

Prof Brian Ripley wrote:
> When you linked to ../examples/ R was not involved, and what you are 
> seeing is what your browser did with a file:// url.  Most browsers will 
> support a wide range of file types, and list directories: but that is 
> not something that was ever (AFAICS) documented to work.
> The 'issue' is your expectations when creating your own 
> inst/doc/index.html.  The only relative links that are supported by the 
> help system are to R package help topics and files, to documentation 
> under R.home("doc") and a limited set of files in a package's 'doc' 
> directory to support its use for vignettes, including the ability to 
> list 'doc' itself (if requested in a particular way).
> If links to files under <pkg>/example worked, it was a bug. Because of 
> security concerns over traffic snooping, what you can see through the 
> dynamic help system is intentionally very limited.  In fact I suspect 
> they worked for you only because
> (i) you installed into .Library
> (ii) you had a file for which text/plain worked (and that is because 
> files that might be in a vignette directory have been checked)..
> (iii) you fell into a code branch marked '# should not get here' in 
> pre-2.10.0 (but absent in R-devel).
> The good news is that if you refer to files under the installed 'doc' 
> directory this should work -- subdirectory listings work now in R-devel 
> and will probably be ported to 2.10.0 before release.

Many thanks for clarification and the good news, i.e. for allowing html 
links to /doc (and also to DESCRIPTION).

Let me add one additional suggestion: Yes, I know that there are certain 
related functions available (with different semantics), but what about 
allowing html links to "/demo" and to some other special files like NEWS 
and LICENSE (as found in MASS) or THANKS (like in Hmisc)?

Thanks for consideration.

Thomas Petzoldt

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