Using another R implementation

R is both a language and an implementation of that language. So far, when we've been talking about the R environment/platform, we've been talking about the GNU Project started by R. Ihaka and R. Gentlemen at the University of Auckland in 1993 and hosted at http://www.r-project.org. Since R has no standard specification, this canonical implementation serves as R's de facto specification. If a project is able to implement this specification—and rewrite the GNU-R functionality-for-functionality and bug-for-bug—any valid R code can be run on that implementation.

Sometime around 2009, various other implementation of R started to crop up. Among these are Renjin (running on the Java Virtual Machine), pqR (which stands for Pretty Quick R, and written in a mix of C, R, and Fortran), FastR (which is written in Java), and Riposte (which is written mainly in C++). These alternative implementations promise compelling improvements to GNU-R, such as automatic multithreading...