Language/Symantic/Type/Var.hs

   1 {-# LANGUAGE FlexibleContexts #-}
   2 {-# LANGUAGE FlexibleInstances #-}
   3 {-# LANGUAGE GADTs #-}
   4 {-# LANGUAGE MultiParamTypeClasses #-}
   5 {-# LANGUAGE PatternSynonyms #-}
   6 {-# LANGUAGE TypeFamilies #-}
   7 {-# LANGUAGE ScopedTypeVariables #-}
   8 {-# LANGUAGE UndecidableInstances #-}
   9 {-# OPTIONS_GHC -fno-warn-missing-methods #-}
  10 {-# OPTIONS_GHC -fno-warn-orphans #-}
  11 -- | Type variable.
  12 module Language.Symantic.Type.Var
  13  ( module Language.Symantic.Type.Var
  14  , module Language.Symantic.Lib.Data.Peano
  15  ) where
  16
  17 import Data.Type.Equality ((:~:)(Refl))
  18 import Language.Symantic.Type.Common
  19 import Language.Symantic.Lib.Data.Peano
  20
  21 -- * Type 'Var0'
  22 newtype Var0 = Var0 EPeano
  23 type instance Host_of EPeano = Var0
  24
  25 -- | Undefined instance required to build errors.
  26 instance Eq Var0
  27 -- | Undefined instance required to build errors.
  28 instance Ord Var0
  29
  30 -- * Type 'Var1'
  31 newtype Var1 a = Var1 EPeano
  32 type instance Host1_of EPeano = Var1
  33
  34 -- * Type 'Type_Var0'
  35 -- | The variable type of kind @*@.
  36 type Type_Var0 = Type_Type0 EPeano
  37
  38 pattern Type_Var0 :: SPeano p -> Type_Var0 root Var0
  39 pattern Type_Var0 p = Type_Type0 (EPeano p)
  40
  41 instance Eq_Type1 (Type_Var0 root) where
  42 instance -- String_from_Type
  43  String_from_Type (Type_Var0 root) where
  44         string_from_type (Type_Type0 (EPeano p)) =
  45                 "t" ++ show (integral_from_peano p::Integer)
  46 instance Constraint_Type Eq (Type_Var0 root) where
  47         constraint_type _c Type_Type0{} = Just Dict
  48
  49 -- | Inject 'Type_Var0' within a root type.
  50 type_var0 :: Lift_Type_Root Type_Var0 root => SPeano p -> root Var0
  51 type_var0 = lift_type_root . Type_Type0 . EPeano
  52
  53 -- * Type 'Type_Var1'
  54 -- | The variable type of kind @* -> *@.
  55 type Type_Var1 = Type_Type1 EPeano
  56 instance Constraint_Type Eq (Type_Var1 root)
  57
  58 pattern Type_Var1 :: SPeano p -> root a -> Type_Var1 root (Var1 a)
  59 pattern Type_Var1 p a = Type_Type1 (EPeano p) a
  60
  61 instance Eq_Type1 (Type_Var1 root) where
  62         eq_type1 (Type_Type1 p1 _) (Type_Type1 p2 _)
  63          | p1 == p2
  64          = Just Refl
  65         eq_type1 _ _ = Nothing
  66 instance -- String_from_Type
  67  String_from_Type root =>
  68  String_from_Type (Type_Var1 root) where
  69         string_from_type (Type_Type1 (EPeano p) a) =
  70                 "t_" ++ show (integral_from_peano p::Integer) ++
  71                 " " ++ string_from_type a
  72
  73 -- | Inject 'Type_Var1' within a root type.
  74 type_var1 :: Lift_Type_Root Type_Var1 root => SPeano p -> root a -> root (Var1 a)
  75 type_var1 p = lift_type_root . Type_Var1 p