#10039: Make Const (Control.Applicative) kind polymorphic in its second argument -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: ekmett Type: feature request | Status: new Priority: normal | Milestone: Component: Core Libraries | Version: 7.8.4 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by Iceland_jack): Another example of a kind polymorphic `Const` is in the paper [[http://www .andres-loeh.de/TrueSumsOfProducts/TrueSumsOfProducts.pdf|True Sums of Products]] by Edsko de Vries and Andres Löh, defined in section '''2. Preliminaries''': {{{#!hs newtype I (a :: *) = I { unI :: a } newtype K (a :: *) (b :: k) = K { unK :: a } }}} noting: These are similar to their definitions in the standard libraries (called `Identity` and `Constant`, respectively), but the definition of `K` makes use of GHC's `PolyKinds` extension and is ''kind polymorphic''; we will need this generality. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10039#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler