The allure of Shen is that it offers a type system that is, roughly speaking, very similar to what you get with clojure.spec. You construct "predicates", what S

The allure of Shen is that it offers a type system that is, roughly speaking, very similar to what you get with clojure.spec. You construct "predicates", what Shen calls sequents, which hold about your data. Shen goes a step further than clojure.spec in that it offers a way to prove that those predicates hold locally to each function and globally through your program. I wonder if it might be possible to feed predicates from clojure.spec to the inference engine/type checker from the Shen java port to gain static type checking. I wish I had more time to work on this kind of fundamental research, but alas I'm merely a working programmer schlepping data to and fro.