This blog is updated daily..
A general description is here.
Package help is now converted from Rd by the R-based converters that were first introduced in 2.9.0. This means
- Packages that were installed by R-devel after 2009-08-09 should not be used with earlier versions of R, and some aspects of package help will be missing if there are so used. (Text, HTML and latex help and the runnable examples.)
- Text, HTML and latex help and examples for packages installed under the new system isare converted on-demand from stored parsed Rd files. (Conversions stored in R < 2.10.0 are used if no parsed Rd files are found.)
- Rd version 2 is required in help files.
HTML help is now generated dynamically using a HTTP server running in the R process and listening on the loopback interface.
- Those who need to worry about security implications of such a server can disable it by setting the environment variable R_DISABLE_HTTPD to a non-empty value. This disables help.start() and HTML help (so text help is shown instead).
- The Java/Javascript search engine has been replaced by an HTML interface to help.search(). help.start() no longer has an argument 'searchEngine' as it is no longer needed.
- The dynamicHTML help can now locate cross-references of the form \link[pkg]{foo} and \link[pkg:foo]{bar} where 'foo' is an alias in the package, rather than the documented (basename of a) filenamefilename (since the documnetation has been much ignored).
- Details may change before release.
help.start() no longer sets options(htmlhelp = TRUE) (it used to on Unix but not on Windows). Nor does it on Unix reset the "browser" option if given an argument of that name.
Arguments 'update' and 'remote' are now available on all platforms: the default is update = FALSE since the http server will update the package index at first use.