[Rd] Top-level code in packages

[Frank E Harrell Jr]

Brian Ripley stated that in the future it will not be a good idea to 
have top-level code in R packages other than assignments.  There is one 
important exception, though it leads instantly to an assignment.  To 
maintain compatibility across multiple platforms (R, S-Plus, and more 
than one version of each, Windows, Linux, etc.) I frequently use if( ) 
statements to conditionally define functions depending on the operating 
system and the version of R or S-Plus in effect.

Frank
-- 
Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University