The Rcpp package provides R functions as well as a C++ library which facilitate the integration of R and C++
R data types (SEXP) are matched to C++ objects in a class hierarchy. All R
types are supported (vectors, functions, environment, etc ...) and each
type is mapped to a dedicated class. For example, numeric vectors are
represented as instances of the Rcpp::NumericVector class, environments are
represented as instances of Rcpp::Environment, functions are represented as
Rcpp::Function, etc ...
The
Rcpp-introduction
vignette (also published as a JSS paper) provides a good
entry point to Rcpp as do the Rcpp website, the
Rcpp page and the
Rcpp Gallery. Full documentation
is provided by the Rcpp book.
Conversion from C++ to R and back is driven by the templates Rcpp::wrap
and Rcpp::as which are highly flexible and extensible, as documented
in the Rcpp-extending vignette.
Rcpp also provides Rcpp modules, a framework that allows exposing C++ functions and classes to the R level. The [Rcpp-modules]((http://cran.r-project.org/web/packages/Rcpp/vignettes/Rcpp-modules.pdf) vignette details the current set of features of Rcpp-modules.
Rcpp includes a concept called Rcpp sugar that brings many R functions into C++. Sugar takes advantage of lazy evaluation and expression templates to achieve great performance while exposing a syntax that is much nicer to use than the equivalent low-level loop code. The [Rcpp-sugar]((http://cran.r-project.org/web/packages/Rcpp/vignettes/Rcpp-sugar.pdf) gives an overview of the feature.
Rcpp attributes provide a high-level syntax for declaring C++ functions as callable from R and automatically generating the code required to invoke them. Attributes are intended to facilitate both interactive use of C++ within R sessions as well as to support R package development. Attributes are built on top of Rcpp modules and their implementation is based on previous work in the inline package. See the [Rcpp-atttributes]((http://cran.r-project.org/web/packages/Rcpp/vignettes/Rcpp-attributes.pdf) vignettes for more details.
Many examples are included, and over 800 unit tests in over 400 unit test functions provide additional usage examples.
An earlier version of Rcpp, containing what we now call the 'classic Rcpp API' was written during 2005 and 2006 by Dominick Samperi. This code has been factored out of Rcpp into the package RcppClassic, and it is still available for code relying on the older interface. New development should always use this Rcpp package instead.
Additional documentation is available via the JSS paper by Eddelbuettel and Francois (2011, JSS) paper and the book by Eddelbuettel (2013, Springer); see 'citation("Rcpp")' for details.
Released and tested versions of Rcpp are available via the CRAN network, and can be installed from within R via
install.packages("Rcpp")To install Rcpp snapshots directly from the master branch at GitHub, do
install.packages("devtools")
devtools::install_github("RcppCore/Rcpp")To install from source, ensure you have a complete package development environment.
Also see questions 1.2 and 1.3 in the Rcpp-FAQ.