This commit is contained in:
Nikita Volkov 2015-11-09 07:10:40 +03:00
parent 5c9cc57ab2
commit 535b910fea
2 changed files with 54 additions and 5 deletions

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@ -37,6 +37,10 @@ import Data.Profunctor.Unsafe as Exports
import Data.Functor.Contravariant as Exports
import Data.Functor.Contravariant.Divisible as Exports
-- contravariant-extras
-------------------------
import Contravariant.Extras as Exports
-- either
-------------------------
import Control.Monad.Trans.Either as Exports

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@ -47,16 +47,33 @@ import qualified Hasql.Prelude as Prelude
-------------------------
-- |
-- Serializer of some representation of a parameters product.
-- Serializer of some representation of the parameters product.
--
-- Has instances of 'Contravariant', 'Divisible' and 'Monoid',
-- which you can use to compose multiple parameters together.
-- E.g.,
--
-- >someParamsSerializer :: Params (Int64, Maybe Text)
-- >someParamsSerializer =
-- > contramap fst (value int8) <>
-- > contramap snd (nullableValue text)
-- @
-- someParamsSerializer :: Params (Int64, Maybe Text)
-- someParamsSerializer =
-- 'contramap' fst (value int8) <>
-- 'contramap' snd (nullableValue text)
-- @
--
-- As a general solution for tuples of any arity, instead of 'fst' and 'snd',
-- consider such solutions as
-- the @<http://hackage.haskell.org/package/tuple-th-0.2.5/docs/TupleTH.html#v:proj proj>@ macro.
--
-- Alternatively you can achieve the same using the functions of the @contrazip@ family
-- from the \"contravariant-extras\" package,
-- which are especially helpful when dealing with tuples.
-- E.g.,
--
-- @
-- someParamsSerializer :: Params (Int64, Maybe Text)
-- someParamsSerializer =
-- 'contrazip2' (value int8) (nullableValue text)
-- @
--
newtype Params a =
Params (Params.Params a)
@ -195,6 +212,8 @@ json :: Value Aeson.Value
json =
Value (Value.unsafePTI PTI.json (const Encoder.json))
-- |
-- Unlifts the 'Array' serializer to the plain 'Value' serializer.
{-# INLINABLE array #-}
array :: Array a -> Value a
array (Array imp) =
@ -317,19 +336,45 @@ instance Default (Value Aeson.Value) where
-- * Array
-------------------------
-- |
-- A generic array serializer.
--
-- Here's an example of its usage:
--
-- >x :: Value [[Int64]]
-- >x =
-- > array (arrayDimension foldl' (arrayDimension foldl' (arrayValue int8)))
--
newtype Array a =
Array (Array.Array a)
-- |
-- Lifts the 'Value' serializer into the 'Array' serializer of a non-nullable value.
{-# INLINABLE arrayValue #-}
arrayValue :: Value a -> Array a
arrayValue (Value (Value.Value elementOID arrayOID encoder')) =
Array (Array.value elementOID arrayOID encoder')
-- |
-- Lifts the 'Value' serializer into the 'Array' serializer of a nullable value.
{-# INLINABLE arrayNullableValue #-}
arrayNullableValue :: Value a -> Array (Maybe a)
arrayNullableValue (Value (Value.Value elementOID arrayOID encoder')) =
Array (Array.nullableValue elementOID arrayOID encoder')
-- |
-- A serializer of an array dimension,
-- which thus provides support for multidimensional arrays.
--
-- Accepts:
--
-- * An implementation of the left-fold operation,
-- such as @Data.Foldable.'foldl''@,
-- which determines the input value.
--
-- * A component serializer, which can be either another 'arrayDimension',
-- 'arrayValue' or 'arrayNullableValue'.
--
{-# INLINABLE arrayDimension #-}
arrayDimension :: (forall a. (a -> b -> a) -> a -> c -> a) -> Array b -> Array c
arrayDimension foldl (Array imp) =