R turned into a language which used older Lisp features. It no longer resembles Scheme, but both older and then newer Lisp systems. It even provides OOP derived

R turned into a language which used older Lisp features. It no longer resembles Scheme, but both older and then newer Lisp systems. It even provides OOP derived from CLOS. It's really a vey strange language which provides/uses a lot of features, which can make it difficult to maintain (my guess having read about the language, but have not used it). For example a mix of lazy evaluation and fexprs can make understanding and predicting the behavior of code very difficult.