Servant.EDE.Internal.ToObject

Documentation

class ToObject a where

Turn haskell values into JSON objects.

This is the mechanism used by EDE to marshall data from Haskell to the templates. The rendering is then just about feeding the resulting Object to a compiled Template. Example:

import Text.EDE

data User = User { name :: String, age :: Int }

instance ToObject User where
  toObject user =
    fromPairs [ "name" .= name user
              , "age"  .= age user
              ]

However, you're not forced to write the instance yourself for such a type. Indeed, for any record type (i.e a datatype with a single constructor and with field selectors) you can let GHC.Generics derive the ToObject instance for you.

data User = User { name :: String, age :: Int } deriving Generic
instance ToObject User

This will generate an equivalent instance to the previous one.

Minimal complete definition

Nothing

Methods

toObject :: a -> Object

Turn values of type a into JSON Objects.

-- Reminder:
type Object = HashMap Text Value

Instances

ToObject (HashMap Text Value)

class GToObject f where

Methods

gtoObject :: f a -> Object

Instances

GToObject V1

GToObject U1

(GToObject f, GToObject g) => GToObject ((:*:) f g)

GToObject a => GToObject (M1 D d a)

GToObject a => GToObject (M1 C c a)

(Selector s, ToJSON a) => GToObject (M1 S s (K1 r a))

genericToObject :: (Generic a, GToObject (Rep a)) => a -> Object