Rep.purs

moduleData.Generic.Rep
 ( classGeneric
 , to
 , from
 , repOf
 , NoConstructors
 , NoArguments(..)
 , Sum(..)
 , Product(..)
 , Constructor(..)
 , Argument(..)
 ) where

importData.Semigroup ((<>))
importData.Show (classShow, show)
importData.Symbol (classIsSymbol, reflectSymbol)
importData.Void (Void)
importType.Proxy (Proxy(..))

-- | A representation for types with no constructors.
newtypeNoConstructors = NoConstructorsVoid

-- | A representation for constructors with no arguments.
dataNoArguments = NoArguments

instanceshowNoArguments :: ShowNoArgumentswhere
 show _ = "NoArguments"

-- | A representation for types with multiple constructors.
dataSumab = Inla|Inrb

instanceshowSum :: (Showa, Showb) =>Show (Sumab) where
 show (Inl a) = "(Inl " <> show a <> ")"
 show (Inr b) = "(Inr " <> show b <> ")"

-- | A representation for constructors with multiple fields.
dataProductab = Productab

instanceshowProduct :: (Showa, Showb) =>Show (Productab) where
 show (Product a b) = "(Product " <> show a <> "" <> show b <> ")"

-- | A representation for constructors which includes the data constructor name
-- | as a type-level string.
newtypeConstructor (name :: Symbol) a = Constructora

instanceshowConstructor :: (IsSymbolname, Showa) =>Show (Constructornamea) where
 show (Constructor a) = "(Constructor @" <> show (reflectSymbol (Proxy::Proxyname)) <> "" <> show a <> ")"

-- | A representation for an argument in a data constructor.
newtypeArgumenta = Argumenta

instanceshowArgument :: Showa=>Show (Argumenta) where
 show (Argument a) = "(Argument " <> show a <> ")"

-- | The `Generic` class asserts the existence of a type function from types
-- | to their representations using the type constructors defined in this module.
classGenericarep | a->repwhere
to::rep->a
from::a->rep

repOf::forallarep. Genericarep=>Proxya->Proxyrep
repOf _ = Proxy