[R-SIG-Mac] Executing older intalled versions of R

[Gregory Warnes]

Hi All,

For some automated software building, I need to be able to execute  
older versions of R via the command line.  Currently, even if I  
provide the full path to the R shell script, the current version of R  
gets executed.  For instance,

	/Library/Frameworks/R.framework/Versions/2.4/Resources/bin/R --version
	R version 2.6.2 (2008-02-08)
	Copyright (C) 2008 The R Foundation for Statistical Computing
	ISBN 3-900051-07-0
	[...]

and

	[Straight:~] warnes% /Library/Frameworks/R.framework/Versions/2.4/ 
Resources/bin/R RHOME
	/Library/Frameworks/R.framework/Resources

and

	[Straight:~] warnes% /Library/Frameworks/R.framework/Versions/2.4/ 
Resources/bin/R
	
	R version 2.6.2 (2008-02-08)
	Copyright (C) 2008 The R Foundation for Statistical Computing
	ISBN 3-900051-07-0
	[...]


Is there a particular reason why the R shell script defines

	R_HOME_DIR=/Library/Frameworks/R.framework/Resources

instead of

	VERSION=2.4 # or whatever
	R_HOME_DIR=/Library/Frameworks/R.framework/Versions/$VERSION$/Resources

with similar changes through the rest of the file?

-Greg