17  Foreign Function Interfaces (FFI)

Objective

Understand the concept of FFI and broadly how it works with respect to R.

Foreign function interfaces (FFI) are mechanisms by which other (foreign) languages can be used in our programming langauge of choice. They are typically used to call compiled languages (like C / Rust) from an interpretted langauge (R).

Much of R’s success and power comes from a robust FFI tooling ecosystem. Some of the more prominent FFI libraries are:

Package	Language
Rcpp	C++
cpp11	C++
rJava	Java
V8	JavaScript & WASM

R’s C API

Most langauges have the ability to interact with C and C-types. R is written in C and exposes a C API. Rust is able to work with C and represent C types. This is where extendr comes in.