R is a widely used, growing language often used in Data Science and Statistics.

While it does not have a published formal specification, there is a draft specification that describes lexing and parsing the language.

In the most widely used implementation the parsing is done with a bison parser defined in gram.y.

The lexing rules for R are somewhat complex, but the parsing is relatively straightforward, as generally everything is an expression.

It would very beneficial to the R community to have support for R in semantic!