Language/LOL/Symantic/Type/Bool.hs

   1 {-# LANGUAGE FlexibleContexts #-}
   2 {-# LANGUAGE GADTs #-}
   3 {-# LANGUAGE MultiParamTypeClasses #-}
   4 {-# LANGUAGE OverloadedStrings #-}
   5 {-# LANGUAGE ScopedTypeVariables #-}
   6 {-# LANGUAGE TypeFamilies #-}
   7 {-# LANGUAGE UndecidableInstances #-}
   8 module Language.LOL.Symantic.Type.Bool where
   9
  10 import Data.Maybe (isJust)
  11 import Data.Type.Equality ((:~:)(Refl))
  12
  13 import Language.LOL.Symantic.Type.Common
  14 import Language.LOL.Symantic.Type.Fun
  15 import Language.LOL.Symantic.Type.Var
  16
  17 -- * Type 'Type_Bool'
  18 -- | The 'Bool' type.
  19 data Type_Bool (root:: * -> *) h where
  20         Type_Bool :: Type_Bool root Bool
  21 type instance Root_of_Type      (Type_Bool root) = root
  22 type instance Error_of_Type ast (Type_Bool root) = ()
  23
  24 instance -- Type_Eq
  25  Type_Eq (Type_Bool root) where
  26         type_eq Type_Bool Type_Bool = Just Refl
  27 instance -- Eq
  28  Eq (Type_Bool root h) where
  29         x == y = isJust $ x `type_eq` y
  30 instance -- String_from_Type
  31  String_from_Type (Type_Bool root) where
  32         string_from_type Type_Bool = "Bool"
  33 instance -- Show
  34  Show (Type_Bool root h) where
  35         show = string_from_type
  36 instance Type_Constraint Eq (Type_Bool root) where
  37         type_constraint _c Type_Bool = Just Dict
  38 instance Type_Constraint Ord (Type_Bool root) where
  39         type_constraint _c Type_Bool = Just Dict
  40
  41 -- | Convenient alias to include a 'Type_Bool' within a type.
  42 type_bool :: Type_Root_Lift Type_Bool root => root Bool
  43 type_bool = type_root_lift Type_Bool
  44
  45 -- * Type 'Type_Fun_Bool'
  46 -- | Convenient alias.
  47 type Type_Fun_Bool lam
  48  = Type_Root (Type_Alt  Type_Var
  49              (Type_Alt (Type_Fun lam)
  50                         Type_Bool))