What exactly is the kind “*” in Haskell?
First off, * is not a wildcard! It’s also typically pronounced “star.” Bleeding edge note: There is as of Feb. 2015 a proposal to simplify GHC’s subkind system (in 7.12 or later). That page contains a good discussion of the GHC 7.8/7.10 story. Looking forward, GHC may drop the distinction between types and kinds, with … Read more