The R Core Group has released the latest update to open-source R, R 2.13.0 is now available. You can download the new source distribution from the R Project website, and I see from the Download R tool at inside-R.org that binaries for Windows and Mac are already available at my local CRAN mirror (and, shortly, yours too).
The (long) list of updates is, as always, in the NEWS file. But by far the most significant addition to this release is the introduction of a byte compiler. The new compiler function will convert functions in the R language to byte-code, and byte-compiled functions promise to execute faster than ordinary R functions. At the moment, the standard R functions are not byte-compiled yet, but if you build R from source you can compile them yourself as the R Installation and Administration Manual explains. You can also compile your own functions with the new "compile" command (in the included compiler package). Dirk Eddelbuettel has done some byte-compilation benchmarks with some small R functions, and has seen up to threefold performance gains for very little cost (i.e. having to byte-compile the function). Nice! If you've seen performance benefits from byte-compilation, let us know in the comments.
As always, thanks to the R Core group for these continued advances to R.
r-announce mailing list: R 2.13.0 is released