[R-SIG-Mac] RSwitch - making it easier to test pre-release versions of R

[Simon Urbanek]

In case you didn't know it is possible to have multiple R versions  
installed on your Mac. The R framework uses a versioning system that  
can keep multiple R versions in parallel at /Library/Frameworks/ 
R.framework/Versions
You can change the current version by setting the "Current" symlink  
there. For those as lazy as me there is now a small GUI tool now  
available at
http://r.research.att.com/
(on the bottom) which I call RSwitch and it allows you to change the  
current R version in one click. Since we are getting close to the  
beta stage of the next release, the best use of it is once you  
install the current alpha/beta version of R to switch between the pre- 
release and your old R version as necessary.

Note: even if you switch the current R version, you will still need  
to use the corresponding version of the GUI as well, otherwise  
strange things will happen. Switching versions while R is running can  
also have undesirable effects if you try to load packages after the  
change as they will be loaded from the wrong version of R, so use  
with care.

Cheers,
Simon