symantic-lib/Language/Symantic/Lib/Functor.hs

   1 {-# LANGUAGE UndecidableInstances #-}
   2 {-# OPTIONS_GHC -fno-warn-orphans #-}
   3 -- | Symantic for 'Functor'.
   4 module Language.Symantic.Lib.Functor where
   5
   6 import Control.Monad (liftM2)
   7 import qualified Data.Function as Fun
   8 import Data.Functor (Functor)
   9 import qualified Data.Functor as Functor
  10 import Data.Proxy (Proxy(..))
  11 import Data.Type.Equality
  12 import Prelude hiding (Functor(..))
  13
  14 import Language.Symantic.Parsing
  15 import Language.Symantic.Typing
  16 import Language.Symantic.Compiling
  17 import Language.Symantic.Interpreting
  18 import Language.Symantic.Transforming
  19 import Language.Symantic.Lib.Lambda
  20
  21 -- * Class 'Sym_Functor'
  22 class Sym_Lambda term => Sym_Functor term where
  23         fmap :: Functor f => term (a -> b) -> term (f a) -> term (f b)
  24         default fmap
  25          :: (Trans t term, Functor f)
  26          => t term (a -> b)
  27          -> t term (f a)
  28          -> t term (f b)
  29         fmap = trans_map2 fmap
  30
  31         (<$) :: Functor f => term a -> term (f b) -> term (f a); infixl 4 <$
  32         (<$) a = fmap (lam (Fun.const a))
  33
  34
  35 type instance Sym_of_Iface (Proxy Functor) = Sym_Functor
  36 type instance TyConsts_of_Iface (Proxy Functor) = Proxy Functor ': TyConsts_imported_by Functor
  37 type instance TyConsts_imported_by Functor = '[]
  38
  39 instance Sym_Functor HostI where
  40         fmap = liftM2 Functor.fmap
  41         (<$) = liftM2 (Functor.<$)
  42 instance Sym_Functor TextI where
  43         fmap = textI2 "fmap"
  44         (<$) = textI_infix "<$" (infixL 4)
  45 instance (Sym_Functor r1, Sym_Functor r2) => Sym_Functor (DupI r1 r2) where
  46         fmap = dupI2 @Sym_Functor fmap
  47         (<$) = dupI2 @Sym_Functor (<$)
  48
  49 -- | 'fmap' alias.
  50 (<$>) :: (Sym_Functor term, Functor f)
  51  => term (a -> b) -> term (f a) -> term (f b)
  52 (<$>) = fmap
  53 infixl 4 <$>
  54
  55 instance
  56  ( Read_TyNameR TyName cs rs
  57  , Inj_TyConst cs Functor
  58  ) => Read_TyNameR TyName cs (Proxy Functor ': rs) where
  59         read_TyNameR _cs (TyName "Functor") k = k (ty @Functor)
  60         read_TyNameR _rs raw k = read_TyNameR (Proxy @rs) raw k
  61 instance Show_TyConst cs => Show_TyConst (Proxy Functor ': cs) where
  62         show_TyConst TyConstZ{} = "Functor"
  63         show_TyConst (TyConstS c) = show_TyConst c
  64
  65 instance Proj_TyConC cs (Proxy Functor)
  66 data instance TokenT meta (ts::[*]) (Proxy Functor)
  67  = Token_Term_Functor_fmap   (EToken meta ts) (EToken meta ts)
  68  | Token_Term_Functor_const (EToken meta ts) (EToken meta ts)
  69 deriving instance Eq_Token meta ts => Eq (TokenT meta ts (Proxy Functor))
  70 deriving instance Show_Token meta ts => Show (TokenT meta ts (Proxy Functor))
  71 instance -- CompileI
  72  ( Inj_TyConst cs Functor
  73  , Inj_TyConst cs (->)
  74  , Proj_TyCon  cs
  75  , Compile cs is
  76  ) => CompileI cs is (Proxy Functor) where
  77         compileI tok ctx k =
  78                 case tok of
  79                  Token_Term_Functor_fmap tok_a2b tok_fa ->
  80                         -- fmap :: Functor f => (a -> b) -> f a -> f b
  81                         compileO tok_a2b ctx $ \ty_a2b (TermO a2b) ->
  82                         compileO tok_fa  ctx $ \ty_fa  (TermO fa) ->
  83                         check_TyEq2 (ty @(->))
  84                          (At (Just tok_a2b) ty_a2b) $ \Refl ty_a2b_a ty_a2b_b ->
  85                         check_TyCon1 (ty @Functor)
  86                          (At (Just tok_fa) ty_fa) $ \Refl TyCon ty_fa_f ty_fa_a ->
  87                         check_TyEq
  88                          (At (Just tok_a2b) ty_a2b_a)
  89                          (At (Just tok_fa) ty_fa_a) $ \Refl ->
  90                         k (ty_fa_f :$ ty_a2b_b) $ TermO $
  91                          \c -> fmap (a2b c) (fa c)
  92                  Token_Term_Functor_const tok_a tok_fb ->
  93                         -- (<$) :: Functor f => a -> f b -> f a
  94                         compileO tok_a  ctx $ \ty_a  (TermO a) ->
  95                         compileO tok_fb ctx $ \ty_fb (TermO fb) ->
  96                         check_TyCon1 (ty @Functor)
  97                          (At (Just tok_fb) ty_fb) $ \Refl TyCon ty_fb_f _ty_fb_b ->
  98                         k (ty_fb_f :$ ty_a) $ TermO $
  99                          \c -> (<$) (a c) (fb c)
 100 instance -- TokenizeT
 101  Inj_Token meta ts Functor =>
 102  TokenizeT meta ts (Proxy Functor) where
 103         tokenizeT _t = mempty
 104          { tokenizers_infix = tokenizeTMod []
 105                  [ tokenize2 "fmap" infixN5   Token_Term_Functor_fmap
 106                  , tokenize2 "<$"  (infixL 4) Token_Term_Functor_const
 107                  , tokenize2 "<$>" (infixL 4) Token_Term_Functor_fmap
 108                  ]
 109          }
 110 instance Gram_Term_AtomsT meta ts (Proxy Functor) g