Comment by bachmeier

I took a couple stabs at this long ago (even before there was a Typescript for inspiration). The first attempt was to add types to the syntax of R, but that would have required a lot more time than I had. Properly catching errors is a massive undertaking requiring a lot of background I don't have. The second attempt was to add syntax for types to R and then compile the code to another language. That's easy to do, but really boring, so I wasn't able to stick with it. It comes with the advantages of static typing and R code that runs very fast. I gave up and went with embedding R inside a statically typed language. Very happy with my choice.

Good luck to the authors of this. I believe it solves an important problem for R package authors and others wanting to write bigger programs. It's hard to argue with the benefits of static typing for this type of work.