{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE PatternSynonyms #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
module Language.Symantic.Type.Either where

import Data.Proxy
import Language.Symantic.Type.Root
import Language.Symantic.Type.Type0
import Language.Symantic.Type.Type2

-- * Type 'Type_Either'
-- | The 'Either' type.
type Type_Either = Type_Type2 (Proxy Either)

type instance Constraint2_of (Proxy Either)
 = Constraint2_Empty

pattern Type_Either
 :: root a -> root b
 -> Type_Either root (Either a b)
pattern Type_Either a b
 = Type_Type2 Proxy a b

instance -- String_from_Type
 String_from_Type root =>
 String_from_Type (Type_Either root) where
	string_from_type (Type_Type2 _ a b) =
		"Either"
		 ++ " (" ++ string_from_type a ++ ")"
		 ++ " (" ++ string_from_type b ++ ")"

-- | Inject 'Type_Either' within a root type.
type_either
 :: forall root h_a h_b.
 Lift_Type_Root Type_Either root
 => root h_a
 -> root h_b
 -> root (Either h_a h_b)
type_either a b = lift_type_root
	 (Type_Either a b
	 ::Type_Either root (Either h_a h_b))