New functional languages emphasize current research, such as dependent types or algebraic effects, as if the best of the past has naturally been saved. Sometime

New functional languages emphasize current research, such as dependent types or algebraic effects, as if the best of the past has naturally been saved. Sometimes the best of the past gets forgotten. I loved SML; a language designer would do well to internalize its module signature design. One wants to do at least this well, while incorporating current ideas.