See this talk [0] about this addition to Clojure called core.spec [1]. I read the paper first, and it isn't until the end of the presentation that I understood

See this talk [0] about this addition to Clojure called core.spec [1]. I read the paper first, and it isn't until the end of the presentation that I understood how it was related to the feature at all. Basically, core.spec is a kind of formal verification tool designed to deal with the growth of software. It is not a type system, though it resembles one in some ways. The objective is to support comparisons between the signatures of a function at two different points and say, are these compatible? Is this a breaking change? You have to design for growth: make no assumptions about unspecified keys and always assume that later versions may return more than they used to. And so on. If you're a fan of semver, be warned. [0] https://www.youtube.com/watch?v=oyLBGkS5ICk https://www.youtube.com/watch?v=oyLBGkS5ICk https://news.ycombinator.com/item?id=13085952 [1] https://clojure.org/about/spec https://clojure.org/about/spec