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.AST
  14 import Language.LOL.Symantic.Type.Common
  15 import Language.LOL.Symantic.Type.Fun
  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) = Error_Type_Fun ast
  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 $ type_eq x y
  30 instance -- Type_from AST
  31  ( Type_Root_Lift Type_Bool root
  32  , Error_Type_Lift (Error_Type AST) (Error_of_Type AST root)
  33  , Error_Type_Lift (Error_Type_Fun AST) (Error_of_Type AST root)
  34  , Implicit_HBool (Is_Last_Type (Type_Bool root) root)
  35  ) => Type_from AST (Type_Bool root) where
  36         type_from _px_ty ast k =
  37                 case ast of
  38                  AST "Bool" asts ->
  39                         case asts of
  40                          [] -> k $ type_root_lift Type_Bool
  41                          _ -> Left $ error_type_lift $
  42                                 Error_Type_Fun_Wrong_number_of_arguments 0 ast
  43                  _ -> Left $
  44                         case hbool :: HBool (Is_Last_Type (Type_Bool root) root) of
  45                          HTrue  -> error_type_lift $ Error_Type_Unsupported ast
  46                          HFalse -> error_type_lift $ Error_Type_Unsupported_here ast
  47 instance -- String_from_Type
  48  String_from_Type (Type_Bool root) where
  49         string_from_type Type_Bool = "Bool"
  50 instance -- Show
  51  Show (Type_Bool root h) where
  52         show = string_from_type
  53
  54 -- | Convenient alias to include a 'Type_Bool' within a type.
  55 type_bool :: Type_Root_Lift Type_Bool root => root Bool
  56 type_bool = type_root_lift Type_Bool
  57
  58 -- * Type 'Type_Fun_Bool'
  59 -- | Convenient alias.
  60 type Type_Fun_Bool lam = Type_Root (Type_Alt (Type_Fun lam) Type_Bool)