I believe that R was originally an implementation of S in Scheme, because of the restrictive commercial licensing of S and the desire to have a free-as-in-beer

I believe that R was originally an implementation of S in Scheme, because of the restrictive commercial licensing of S and the desire to have a free-as-in-beer alternative that was S-compatible. This comes through in things like R's metaprogramming: https://adv-r.hadley.nz/meta-big-picture.html#meta-big-picture https://adv-r.hadley.nz/meta-big-picture.html#meta-big-pictu...