Language/Symantic/Expr/Tuple.hs

   1 {-# LANGUAGE DefaultSignatures #-}
   2 {-# LANGUAGE FlexibleContexts #-}
   3 {-# LANGUAGE FlexibleInstances #-}
   4 {-# LANGUAGE MultiParamTypeClasses #-}
   5 {-# LANGUAGE ScopedTypeVariables #-}
   6 {-# LANGUAGE TypeFamilies #-}
   7 {-# OPTIONS_GHC -fno-warn-orphans #-}
   8 -- | Expression for 'Tuple'.
   9 module Language.Symantic.Expr.Tuple where
  10
  11 -- import qualified Data.Tuple as Tuple
  12 import Data.Proxy (Proxy(..))
  13 -- import Data.Type.Equality ((:~:)(Refl))
  14 import Prelude hiding (maybe)
  15
  16 import Language.Symantic.Type
  17 import Language.Symantic.Repr.Dup
  18 import Language.Symantic.Trans.Common
  19 import Language.Symantic.Expr.Common
  20 import Language.Symantic.Expr.Functor
  21
  22 -- * Class 'Sym_Tuple_Lam'
  23 -- | Symantic.
  24 class Sym_Tuple2 repr where
  25         tuple2 :: repr a -> repr b -> repr (a, b)
  26         default tuple2 :: Trans t repr => t repr a -> t repr b -> t repr (a, b)
  27         tuple2 = trans_map2 tuple2
  28
  29 instance -- Sym_Tuple2 Dup
  30  ( Sym_Tuple2 r1
  31  , Sym_Tuple2 r2
  32  ) => Sym_Tuple2 (Dup r1 r2) where
  33         tuple2 (a1 `Dup` a2) (b1 `Dup` b2) = tuple2 a1 b1 `Dup` tuple2 a2 b2
  34
  35 instance Constraint1_Type Functor_with_Lambda (Type_Type1 ((,) fst) root) where
  36         constraint1_type _c (Type_Type1 _ _) = Just Dict
  37
  38 -- * Type 'Expr_Tuple2'
  39 -- | Expression.
  40 data Expr_Tuple2 (lam:: * -> *) (root:: *)
  41 type instance Root_of_Expr      (Expr_Tuple2 lam root)      = root
  42 type instance Type_of_Expr      (Expr_Tuple2 lam root)      = Type_Tuple2
  43 type instance Sym_of_Expr       (Expr_Tuple2 lam root) repr = (Sym_Tuple2 repr)
  44 type instance Error_of_Expr ast (Expr_Tuple2 lam root)      = No_Error_Expr
  45
  46 -- | Parsing utility to check that the given type is a 'Type_Tuple2'
  47 -- or raise 'Error_Expr_Type_mismatch'.
  48 check_type_tuple2
  49  :: forall ast ex root ty h ret.
  50  ( root ~ Root_of_Expr ex
  51  , ty ~ Type_Root_of_Expr ex
  52  , Type_Lift   Type_Tuple2 (Type_of_Expr root)
  53  , Type_Unlift Type_Tuple2 (Type_of_Expr root)
  54  , Error_Expr_Lift (Error_Expr (Error_of_Type ast ty) ty ast)
  55                    (Error_of_Expr ast root)
  56  )
  57  => Proxy ex -> ast -> ty h
  58  -> (Type_Tuple2 ty h -> Either (Error_of_Expr ast root) ret)
  59  -> Either (Error_of_Expr ast root) ret
  60 check_type_tuple2 ex ast ty k =
  61         case type_unlift $ unType_Root ty of
  62          Just ty_l -> k ty_l
  63          Nothing -> Left $
  64                 error_expr ex $
  65                 Error_Expr_Type_mismatch ast
  66                  (Exists_Type (type_tuple2 (type_var SZero) (type_var $ SSucc SZero)
  67                  :: Type_Root_of_Expr ex (Zero, Succ Zero)))
  68                  (Exists_Type ty)
  69
  70 -- | Parse 'list_cons'.
  71 tuple2_from
  72  :: forall root lam ty ast hs ret.
  73  ( ty ~ Type_Root_of_Expr (Expr_Tuple2 lam root)
  74  , Eq_Type (Type_Root_of_Expr root)
  75  , Expr_from ast root
  76  , Type_Lift   Type_Tuple2 (Type_of_Expr root)
  77  , Type_Unlift Type_Tuple2 (Type_of_Expr root)
  78  , Error_Expr_Lift (Error_Expr (Error_of_Type ast ty) ty ast)
  79                    (Error_of_Expr ast root)
  80  , Root_of_Expr root ~ root
  81  ) => ast -> ast
  82  -> Expr_From ast (Expr_Tuple2 lam root) hs ret
  83 tuple2_from ast_a ast_b _ex _ast ctx k =
  84         expr_from (Proxy::Proxy root) ast_a ctx $
  85          \(ty_a::Type_Root_of_Expr root h_a) (Forall_Repr_with_Context a) ->
  86         expr_from (Proxy::Proxy root) ast_b ctx $
  87          \(ty_b::Type_Root_of_Expr root h_b) (Forall_Repr_with_Context b) ->
  88         k (type_tuple2 ty_a ty_b) $ Forall_Repr_with_Context $
  89                 \c -> tuple2 (a c) (b c)