check of ::: imports

git-svn-id: https://svn.r-project.org/R/trunk@63580 00db46b3-68df-0310-9c12-caf00c1e9a41
Direct handling of basic arithmetic operations on simple scalars
(similar to pqR's 07-scalar-arith).


git-svn-id: https://svn.r-project.org/R/trunk@63582 00db46b3-68df-0310-9c12-caf00c1e9a41
separate out and clarify the documentation on Depends etc

git-svn-id: https://svn.r-project.org/R/trunk@63583 00db46b3-68df-0310-9c12-caf00c1e9a41