Recursive objects

Hi all,

Does anyone have a comprehensive list of recursive-type objects in R?
is.recursive defines them as by exclusion: "most types of objects are
regarded as recursive, except for  vector types, ?NULL? and symbols
(as given by ?as.name?)."  I think this that means recursive objects
are:

 * lists
 * pairlists
 * calls
 * expressions

Did I miss anything?

Hadley

Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/