[R] user library help functionality (packages.html)

[Duncan Murdoch]

On 1/15/2009 12:50 PM, Jarrett Barber wrote:
> Here's another help file question.
> 
> Some context: University setting wherein R is installed for  
> availability to students and course instructors across campus in  
> various PC labs.  Windows Vista environment.
> 
> Goal: To maximize flexibility and functionality of installing add-on  
> packages and associated help files among different users, while  
> avoiding conflicts across different user libraries.  (I could have my  
> difficult-to-access sysadmin install _all_ libraries, but this seems  
> wasteful, and would seem to present problems when my colleague or I  
> want to update a package or install a newly available package but do  
> not have time to wait a week or two for our sysadmin.)
> 
> Problem (?): As a course instructor, I want flexibility to install add- 
> on libraries to a user (not site) library, and I don't want to step on  
> my colleagues' toes (or vice-versa) when it comes to add-on packages  
> and associated help files for use in classes.  I have no problem  
> installing add-on packages to a user library, with one exception: I do  
> not have permission to update the file $RHOME/doc/html/packages.html,  
> as evidenced by a permission error upon installing a package to a user  
> library using update.packages (not to the default site library, which  
> is also restricted).  The installed add-on packages work fine, with  
> the exception of some of the help functionality.  I find myself having  
> to use browseURL() to point to the html files in the package's file  
> structure.  I cannot expect the average student (or senior colleague)  
> to tolerate this situation.

A simpler way to get to the HTML man pages is to run

options(htmlhelp=TRUE)

and then the regular ?topic or help("topic") will find the HTML help 
pages in your local library.

> 
> I'm thinking that I simply need to have my sysadmin give me and my  
> colleagues (all users who want to install add-ons packages?)  
> permission to read/write packages.html, and the problem will go away.   
> But, before I ask my sysadmin to give permission, I want to know, does  
> this create another problem?  For example, my colleague creates a  
> library for STAT3000BC, which, I assume, will modify packages.html  
> (assuming my sysadmin gives permission), then I create a library for  
> STAT2010, which also modifies packages.html.  See my concern?  Does R  
> somehow allow harmonious help functionality in such cases (by, for  
> example, maintaining separate copies of packages.html for different  
> users)?

You will likely have strange problems if you do that.  The 
doc/html/packages.html file is intended to talk about what is available 
to everyone; I suspect in your scenario, it would be updated to show 
your packages (but not your colleague's) whenever you added one, and 
then updated to show your colleague's packages (but not yours) when he 
added one, and would almost never be right for both of you.

The good news is that it looks as though sometime this year we will make 
quite substantial changes to the way the help system is stored, so a lot 
of things like packages.html could be generated on the fly.

Duncan Murdoch