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Generic.purs
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Generic.purs
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module Data.Show.Generic
( class GenericShow
, genericShow'
, genericShow
, class GenericShowArgs
, genericShowArgs
) where
import Prelude (class Show, show, (<>))
import Data.Generic.Rep
import Data.Symbol (class IsSymbol, reflectSymbol)
import Type.Proxy (Proxy(..))
class GenericShow a where
genericShow' :: a -> String
class GenericShowArgs a where
genericShowArgs :: a -> Array String
instance genericShowNoConstructors :: GenericShow NoConstructors where
genericShow' a = genericShow' a
instance genericShowArgsNoArguments :: GenericShowArgs NoArguments where
genericShowArgs _ = []
instance genericShowSum :: (GenericShow a, GenericShow b) => GenericShow (Sum a b) where
genericShow' (Inl a) = genericShow' a
genericShow' (Inr b) = genericShow' b
instance genericShowArgsProduct
:: (GenericShowArgs a, GenericShowArgs b)
=> GenericShowArgs (Product a b) where
genericShowArgs (Product a b) = genericShowArgs a <> genericShowArgs b
instance genericShowConstructor
:: (GenericShowArgs a, IsSymbol name)
=> GenericShow (Constructor name a) where
genericShow' (Constructor a) =
case genericShowArgs a of
[] -> ctor
args -> "(" <> intercalate " " ([ctor] <> args) <> ")"
where
ctor :: String
ctor = reflectSymbol (Proxy :: Proxy name)
instance genericShowArgsArgument :: Show a => GenericShowArgs (Argument a) where
genericShowArgs (Argument a) = [show a]
-- | A `Generic` implementation of the `show` member from the `Show` type class.
genericShow :: forall a rep. Generic a rep => GenericShow rep => a -> String
genericShow x = genericShow' (from x)
foreign import intercalate :: String -> Array String -> String