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

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

-- * Type 'Type_Tuple2'
-- | The @(,)@ type.
type Type_Tuple2 = Type_Type2 (Proxy (,))

type instance Constraint2_of (Proxy (,))
 = Constraint2_Empty

pattern Type_Tuple2
 :: root a -> root b
 -> Type_Tuple2 root ((,) a b)
pattern Type_Tuple2 a b
 = Type_Type2 Proxy a b

instance -- String_from_Type
 String_from_Type root =>
 String_from_Type (Type_Tuple2 root) where
	string_from_type (Type_Type2 _ a b) =
		"("  ++ string_from_type a ++
		", " ++ string_from_type b ++ ")"

-- | Inject 'Type_Tuple2' within a root type.
type_tuple2
 :: forall root h_a h_b.
 Lift_Type_Root Type_Tuple2 root
 => root h_a
 -> root h_b
 -> root (h_a, h_b)
type_tuple2 a b = lift_type_root
	 (Type_Tuple2 a b
	 ::Type_Tuple2 root (h_a, h_b))