Language/Symantic/Type/Maybe.hs

   1 {-# LANGUAGE FlexibleContexts #-}
   2 {-# LANGUAGE FlexibleInstances #-}
   3 {-# LANGUAGE TypeFamilies #-}
   4 {-# OPTIONS_GHC -fno-warn-orphans #-}
   5 module Language.Symantic.Type.Maybe where
   6
   7 import Data.Proxy
   8
   9 import Language.Symantic.Type.Common
  10
  11 -- * Type 'Type_Maybe'
  12 type Type_Maybe = Type_Type1 Maybe
  13 instance -- String_from_Type
  14  String_from_Type root =>
  15  String_from_Type (Type_Maybe root) where
  16         string_from_type (Type_Type1 _f a) =
  17                 "Maybe" ++ " (" ++ string_from_type a ++ ")"
  18
  19 -- | Inject a 'Type_Maybe' within a root type.
  20 type_maybe
  21  :: Type_Root_Lift Type_Maybe root
  22  => root h_a
  23  -> root (Maybe h_a)
  24 type_maybe = type_root_lift . Type_Type1 (Proxy::Proxy Maybe)