It is good to learn that OO capabilities are almost entirely a set of conventions and how these could be implemented as a DSL, like it have been done many times

It is good to learn that OO capabilities are almost entirely a set of conventions and how these could be implemented as a DSL, like it have been done many times with Common Lisps and Schemes. CLOS is just a DSL. Another case study is Scala language, which is functional in the first place, and uses OO as a convenient way to structure the code, which, together with message passing were Alan Kay's original concepts. OO should be a nice optional add on, not a forsed the only way to do it all as it is in case of Java or Ruby.