[ESS] library(help=foo)

[Stephen Eglen]

> Hi Stephen:
>
> Could you please elaborate?  I have been using library and package
> interchangeably.  What makes a library not a package or vice versa?

Taken from http://cran.r-project.org/doc/manuals/R-exts.html

  A package is not1 a library. The latter is used in two senses in R
  documentation. The first is a directory into which packages are
  installed, e.g. /usr/lib/R/library: in that sense it is sometimes
  referred to as a library directory or library tree (since the library
  is a directory which contains packages as directories, which
  themselves contain directories). ...

...
[1] although this is common mis-usage. It seems to stem from S, whose
analogues of R's packages were officially known as library sections and
later as chapters, but almost always referred to as libraries.

And don't worry, I think most people have made the same mistake!  


Stephen