Language/Symantic/Type/Bool.hs

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