Language/Symantic/Type/Map.hs

   1 {-# LANGUAGE FlexibleContexts #-}
   2 {-# LANGUAGE GADTs #-}
   3 {-# LANGUAGE MultiParamTypeClasses #-}
   4 {-# LANGUAGE OverloadedStrings #-}
   5 {-# LANGUAGE ScopedTypeVariables #-}
   6 {-# LANGUAGE TypeFamilies #-}
   7 module Language.Symantic.Type.Map where
   8
   9 import Data.Map.Strict as Map
  10 import Data.Maybe (isJust)
  11 import Data.Type.Equality ((:~:)(Refl))
  12
  13 import Language.Symantic.Type.Common
  14
  15 -- * Type 'Type_Map'
  16 -- | The 'Map' type.
  17 data Type_Map root h where
  18         Type_Map :: Ord h_k
  19                  => root h_k
  20                  -> root h_a
  21                  -> Type_Map root (Map h_k h_a)
  22
  23 type instance Root_of_Type      (Type_Map root) = root
  24 type instance Error_of_Type ast (Type_Map root) = No_Error_Type
  25
  26 instance -- Type_Eq
  27  Type_Eq root =>
  28  Type_Eq (Type_Map root) where
  29         type_eq (Type_Map k1 a1) (Type_Map k2 a2)
  30          | Just Refl <- k1 `type_eq` k2
  31          , Just Refl <- a1 `type_eq` a2
  32          = Just Refl
  33         type_eq _ _ = Nothing
  34 instance -- Eq
  35  Type_Eq root =>
  36  Eq (Type_Map root h) where
  37         x == y = isJust $ type_eq x y
  38 instance -- String_from_Type
  39  String_from_Type root =>
  40  String_from_Type (Type_Map root) where
  41         string_from_type (Type_Map k a) =
  42                 "Map (" ++ string_from_type k ++ ")"
  43                  ++ " (" ++ string_from_type a ++ ")"
  44 instance -- Show
  45  String_from_Type root =>
  46  Show (Type_Map root h) where
  47         show = string_from_type
  48
  49 -- | Convenient alias to include a 'Type_Map' within a type.
  50 type_map
  51  :: (Type_Root_Lift Type_Map root, Ord h_k)
  52  => root h_k
  53  -> root h_a
  54  -> root (Map h_k h_a)
  55 type_map k a = type_root_lift (Type_Map k a)