more checking that rho is an environment
white-space cleanup (as R-patched has been cleaned)


git-svn-id: https://svn.r-project.org/R/trunk@63420 00db46b3-68df-0310-9c12-caf00c1e9a41
+ some \link{}s

git-svn-id: https://svn.r-project.org/R/trunk@63422 00db46b3-68df-0310-9c12-caf00c1e9a41
Avoid calling install() for  replacement function symbols on each use.


git-svn-id: https://svn.r-project.org/R/trunk@63423 00db46b3-68df-0310-9c12-caf00c1e9a41
Avoid calling install("value") on each replacement function call.


git-svn-id: https://svn.r-project.org/R/trunk@63424 00db46b3-68df-0310-9c12-caf00c1e9a41
Reduce eval() overhead when evaluating constants.


git-svn-id: https://svn.r-project.org/R/trunk@63425 00db46b3-68df-0310-9c12-caf00c1e9a41