Language/Symantic/Type/Tuple.hs

   1 {-# LANGUAGE FlexibleContexts #-}
   2 {-# LANGUAGE FlexibleInstances #-}
   3 {-# LANGUAGE PatternSynonyms #-}
   4 {-# LANGUAGE ScopedTypeVariables #-}
   5 {-# LANGUAGE TypeFamilies #-}
   6 {-# OPTIONS_GHC -fno-warn-orphans #-}
   7 module Language.Symantic.Type.Tuple where
   8
   9 import Data.Proxy
  10 import Language.Symantic.Type.Common
  11
  12 -- * Type 'Type_Tuple2'
  13 -- | The (,) type.
  14 type Type_Tuple2 = Type_Type2 (Proxy (,))
  15
  16 type instance Constraint2_of (Proxy (,))
  17  = Constraint2_Empty
  18
  19 pattern Type_Tuple2
  20  :: root a -> root b
  21  -> Type_Tuple2 root ((,) a b)
  22 pattern Type_Tuple2 a b
  23  = Type_Type2 Proxy a b
  24
  25 instance -- String_from_Type
  26  String_from_Type root =>
  27  String_from_Type (Type_Tuple2 root) where
  28         string_from_type (Type_Type2 _ a b) =
  29                 "("  ++ string_from_type a ++
  30                 ", " ++ string_from_type b ++ ")"
  31
  32 -- | Inject 'Type_Tuple2' within a root type.
  33 type_tuple2
  34  :: forall root h_a h_b.
  35  Lift_Type_Root Type_Tuple2 root
  36  => root h_a
  37  -> root h_b
  38  -> root (h_a, h_b)
  39 type_tuple2 a b = lift_type_root
  40          (Type_Tuple2 a b
  41          ::Type_Tuple2 root (h_a, h_b))