Language/Symantic/Type/Unit.hs

   1 {-# LANGUAGE FlexibleContexts #-}
   2 {-# LANGUAGE FlexibleInstances #-}
   3 {-# LANGUAGE MultiParamTypeClasses #-}
   4 {-# LANGUAGE PatternSynonyms #-}
   5 {-# LANGUAGE ScopedTypeVariables #-}
   6 {-# LANGUAGE TypeFamilies #-}
   7 {-# OPTIONS_GHC -fno-warn-orphans #-}
   8 module Language.Symantic.Type.Unit where
   9
  10 import qualified Data.MonoTraversable as MT
  11 import Data.Proxy
  12
  13 import Language.Symantic.Type.Root
  14 import Language.Symantic.Type.Type0
  15 import Language.Symantic.Type.Constraint
  16 import Language.Symantic.Type.Family
  17
  18 -- * Type 'Type_Unit'
  19 -- | The @()@ type.
  20 type Type_Unit = Type0 (Proxy ())
  21
  22 pattern Type_Unit :: Type_Unit root ()
  23 pattern Type_Unit  = Type0 Proxy
  24
  25 instance Type0_Constraint Eq (Type_Unit root) where
  26         type0_constraint _c Type0{} = Just Dict
  27 instance Type0_Constraint Ord (Type_Unit root) where
  28         type0_constraint _c Type0{} = Just Dict
  29 instance Type0_Constraint Monoid (Type_Unit root)
  30 instance Type0_Constraint Num (Type_Unit root)
  31 instance Type0_Constraint Integral (Type_Unit root)
  32 instance Type0_Constraint MT.MonoFunctor (Type_Unit root)
  33 instance Type0_Family Type_Family_MonoElement (Type_Unit root)
  34 instance String_from_Type (Type_Unit root) where
  35         string_from_type _ = "()"
  36
  37 -- | Inject 'Type_Unit' within a root type.
  38 type_unit :: Type_Root_Lift Type_Unit root => root ()
  39 type_unit = type0