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 somemost aspects of package help (including the runnable examples) will be missing if they 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 are converted on-demand from stored parsed Rd files. (Conversions stored in packages installed under R < 2.10.0 are used if no parsed Rd files are found.)
- Rd version 2 is required in help files. It is recommended that such packages be re-installed.)
HTML help is now generated dynamically using an HTTP server running in the R process and listening on the loopback interface.
- Those who need to worryorried 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 HTML 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) filename (since the documentation has been much ignored).
- Details may change before release.
codocClasses(), which checks consistency of S4 class slots' documentationthe documentation of S4 class slots, now does thisso in considerably more cases. The documentation of inherited slots (from superclasses) is now optional. This affects 'R CMD check <pkg>' when the package defines S4 classes.
[Experimental] File NEWS is now in UTF-8, and has a BOM (often invisible) on the first line, and Emacs local variables set for UTF-8 at the end. RShowDoc("NEWS") should display this correctly, given suitable fonts.
The argument f='f' to showMethods() can be an expression evaluating to a generic function, allowing methods to be shown for non-exported generics and other nonstandard cases.
It is possible to ask for static HTML pages to be prebuilt via the configure option --enable-prebuilt-html. This may be useful for those who wish to make HTML help available outside R, e.g. on a local web site.
help() has a new argument 'help_type' (with default set by the option of that name) to supersede 'offline', 'htmlhelp' and 'chmhelp' (although for now they still work if 'help_type' is unset). There is a new type, "PDF" to allow offline PDF (rather than PostScript).
A function offline_help_helper() will be used if this exists in the workspace or further down the search path, otherwise the function of that name in the 'utils' name space is used.
Plain text help is now used as the fallback for HTML help (as it always has beenwas for Compiled HTML help on Windows).
R CMD INSTALL has a new option --data-compress to control the compression used when lazy-loading data. One new option is --data-compress=bzip2 which will give ca 15% better compression at the expense of slower installation times. Also --data-compress=xz, often giving even better compression on large datasets at the expense of much slownger installation times.
help() arguments 'offline', 'htmlhelp' and 'chmhelp' are deprecated in favour of 'help_type'.
methods::trySilent() is deprecated for try(*, silent=TRUE) or -- more efficiently and flexibly-- - something like tryCatch(*, error= = function(e) e).
Assigning into a raw vector with an index vector containing NAs could cause a segfault. Reported by Hervé Pagès.
Names of datasets could clash with temporary filenames used
when running examples, causing errors.
On systems using zipped data and help (Windows) the names of datasets could clash with temporary filenames used when running examples, causing errors.
cat() on an unopened connection could close it twice, and with file() connections segfaulted on some systems.