This project aims to compile the statistical language R (https://www.r-project.org/) into WASM for use with a browser, via Emscripten (https://emscripten.org/).

Included in the repo is a Dockerfile which can be optionally used to setup an environment and toolchain for compiling R's source code and supporting libraries, written in both C and Fortran. If you are compiling webR without Docker, ensure that you first have the Emscripten SDK installed, along with some required prerequisites:

• cmake
• wget
• quilt
• liblzma
• libpcre2

R's Fortran source files can be compiled with either a custom development version of flang (the default) or with gfortran and Dragonegg (using the --with-dragonegg configure option).

The repo includes patches for R's source code so that it can work in the browser environment provided by Emscripten. The patches also tweak R's interactive mode so as to provide a web-based REPL through the use of jQuery Terminal.

Clone the repo into a new directory, cd into the directory, then run ./configure && make. You can configure make variables in a ~/.webr-config.mk file.

A dist directory is created which when finished contains the R WASM files and an index.html file ready to serve an R REPL.

A demo of the resulting R REPL can be found at https://webr.gwstagg.co.uk/

Loading the page will initally result in a black screen. Please be patient as the WASM runtime downloads and executes. R will display a banner message when it is ready to use.