Sorry- "predicates" == boolean functions. Types operationalize as assertions- boolean functions, predicates, whatever- applied at different stages (to code at c

Sorry- "predicates" == boolean functions. Types operationalize as assertions- boolean functions, predicates, whatever- applied at different stages (to code at compile time, to data at runtime). That's mechanically what types are. Rich Hickey, creator of Clojure, talks more comprehensively about this view in his talk on Clojure Spec (called "Speculation").