GNU R package for Seamless R and C++ Integration

 The Rcpp package provides R functions as well as C++ classes which
 offer a seamless integration of R and C++. Many R data types and objects can be
 mapped back and forth to C++ equivalents which facilitates both writing of new
 code as well as easier integration of third-party libraries. Documentation
 about Rcpp is provided by several vignettes included in this package, via the
 Rcpp Gallery site at http://gallery.rcpp.org, the paper by Eddelbuettel and
 Francois (2011, JSS), and the book by Eddelbuettel (2013, Springer); see
 'citation("Rcpp")' for details on these last two.