{-# LANGUAGE AllowAmbiguousTypes #-}

{- | 'traverse' for generic data types.

TODO This is harder to conceptualize than generic 'foldMap'. No nice clean
explanation yet.

This function can provide generic support for simple parser-esque types.
-}

module Generic.Data.Function.Traverse
  ( GenericTraverse(..)
  , genericTraverseNonSum , GTraverseNonSum
  , GenericTraverseSum(..), PfxTagCfg(..)
  , genericTraverseSum,     GTraverseSum
  , eqShowPfxTagCfg
  ) where

import GHC.Generics

import Generic.Data.Rep.Assert
import Generic.Data.Function.Traverse.NonSum
import Generic.Data.Function.Traverse.Sum
import Generic.Data.Function.Traverse.Constructor

import Data.Text qualified as Text

-- | Generic 'traverse' over a term of non-sum data type @f a@.
genericTraverseNonSum
    :: forall {cd} {gf} asserts f a
    .  ( Generic a, Rep a ~ D1 cd gf
       , GTraverseNonSum cd f gf
       , ApplyGCAsserts asserts f
       , Functor f)
    => f a
genericTraverseNonSum :: forall {cd :: Meta} {gf :: Type -> Type} (asserts :: [GCAssert])
       (f :: Type -> Type) a.
(Generic a, Rep a ~ D1 cd gf, GTraverseNonSum cd f gf,
 ApplyGCAsserts asserts f, Functor f) =>
f a
genericTraverseNonSum = (forall a x. Generic a => Rep a x -> a
to forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall k i (c :: Meta) (f :: k -> Type) (p :: k). f p -> M1 i c f p
M1) forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> forall {k} {k} (cd :: Meta) (f :: k -> Type) (f' :: k -> k)
       (p :: k).
GTraverseNonSum cd f f' =>
f (f' p)
gTraverseNonSum @cd

-- | Generic 'traverse' over a term of sum data type @f a@.
--
-- You must provide a configuration for how to handle constructors.
genericTraverseSum
    :: forall {cd} {gf} opts asserts f a pt
    .  ( Generic a, Rep a ~ D1 cd gf
       , GTraverseSum opts cd f gf
       , ApplyGCAsserts asserts f
       , GenericTraverseC f pt, Functor f)
    => PfxTagCfg pt
    -> f a
genericTraverseSum :: forall {cd :: Meta} {gf :: Type -> Type} (opts :: SumOpts)
       (asserts :: [GCAssert]) (f :: Type -> Type) a pt.
(Generic a, Rep a ~ D1 cd gf, GTraverseSum opts cd f gf,
 ApplyGCAsserts asserts f, GenericTraverseC f pt, Functor f) =>
PfxTagCfg pt -> f a
genericTraverseSum PfxTagCfg pt
ptc = (forall a x. Generic a => Rep a x -> a
to forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall k i (c :: Meta) (f :: k -> Type) (p :: k). f p -> M1 i c f p
M1) forall (f :: Type -> Type) a b. Functor f => (a -> b) -> f a -> f b
<$> forall {k} {k} (opts :: SumOpts) (cd :: k) (f :: Type -> Type)
       (f' :: k -> Type) pt (p :: k).
(GTraverseSum opts cd f f', GenericTraverseC f pt) =>
PfxTagCfg pt -> f (f' p)
gTraverseSum @opts @cd PfxTagCfg pt
ptc

-- | Construct a prefix tag config using existing 'Eq' and 'Show' instances.
--
-- The user only needs to provide the constructor name parser.
eqShowPfxTagCfg :: (Eq a, Show a) => (String -> a) -> PfxTagCfg a
eqShowPfxTagCfg :: forall a. (Eq a, Show a) => (String -> a) -> PfxTagCfg a
eqShowPfxTagCfg String -> a
f = PfxTagCfg
    { pfxTagCfgFromCstr :: String -> a
pfxTagCfgFromCstr = String -> a
f
    , pfxTagCfgEq :: a -> a -> Bool
pfxTagCfgEq = forall a. Eq a => a -> a -> Bool
(==)
    , pfxTagCfgShow :: a -> Text
pfxTagCfgShow = String -> Text
Text.pack forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall a. Show a => a -> String
show
    }