Pinch.Internal.Pinchable

Provides the core Pinchable typeclass and the GPinchable typeclass used to derive instances automatically.

Documentation

class IsTType (Tag a) => Pinchable a where

The Pinchable type class is implemented by types that can be sent or received over the wire as Thrift payloads.

Minimal complete definition

Nothing

Associated Types

type Tag a

TType tag for this type.

For most custom types, this will be TStruct, TUnion, or TException. For enums, it will be TEnum. If the instance automatically derived with use of Generic, this is not required because it is automatically determined by use of Field or Enumeration.

Methods

pinch :: a -> Value (Tag a)

Convert an a into a Value.

For structs, struct, .=, and ?= may be used to construct Value objects tagged with TStruct.

unpinch :: Value (Tag a) -> Either String a

Read a Value back into an a.

For structs, .: and .:? may be used to retrieve field values.

Instances

Pinchable Bool

Pinchable Double

Pinchable Int8

Pinchable Int16

Pinchable Int32

Pinchable Int64

Pinchable ByteString

Pinchable Text

Pinchable a => Pinchable [a]

(Ord a, Pinchable a) => Pinchable (Set a)

(Eq a, Hashable a, Pinchable a) => Pinchable (HashSet a)

Pinchable a => Pinchable (Vector a)

IsTType a => Pinchable (Value a)

(Ord k, Pinchable k, Pinchable v) => Pinchable (Map k v)

(Eq k, Hashable k, Pinchable k, Pinchable v) => Pinchable (HashMap k v)

(.=) :: Pinchable a => Int16 -> a -> FieldPair

Construct a FieldPair from a field identifier and a Pinchable value.

(?=) :: Pinchable a => Int16 -> Maybe a -> FieldPair

Construct a FieldPair from a field identifier and an optional Pinchable value.

struct :: [FieldPair] -> Value TStruct

Construct a Value tagged with a TStruct from the given key-value pairs. Optional fields whose values were omitted will be ignored.

struct [1 .= ("Hello" :: Text), 2 .= (42 :: Int16)]

union :: Pinchable a => Int16 -> a -> Value TUnion

Constructs a Value tagged with TUnion.

union 1 ("foo" :: ByteString)

type FieldPair = (Int16, Maybe SomeValue)

A pair of field identifier and maybe a value stored in the field. If the value is absent, the field will be ignored.

(.:) :: forall a. Pinchable a => Value TStruct -> Int16 -> Either String a

Given a field ID and a Value TStruct, get the value stored in the struct under that field ID. The lookup fails if the field is absent or if it's not the same type as expected by this call's context.

(.:?) :: forall a. Pinchable a => Value TStruct -> Int16 -> Either String (Maybe a)

Given a field ID and a Value TStruct, get the optional value stored in the struct under the given field ID. The value returned is Nothing if it was absent or the wrong type. The lookup fails only if the value retrieved fails to unpinch.

class IsTType (GTag f) => GPinchable f where

GPinchable is used to impelment support for automatically deriving instances of Pinchable via generics.

Associated Types

type GTag f

TType tag to use for objects of this type.

Methods

gPinch :: f a -> Value (GTag f)

Converts a generic representation of a value into a Value.

gUnpinch :: Value (GTag f) -> Either String (f a)

Converts a Value back into the generic representation of the object.

Instances

GPinchable (K1 i Void)

KnownNat n => GPinchable (K1 i (Enumeration n))

(Pinchable a, KnownNat n) => GPinchable (K1 i (Field n (Maybe a)))

(Pinchable a, KnownNat n) => GPinchable (K1 i (Field n a))

genericPinch :: (Generic a, GPinchable (Rep a)) => a -> Value (GTag (Rep a))

Implementation of pinch based on GPinchable.

genericUnpinch :: (Generic a, GPinchable (Rep a)) => Value (GTag (Rep a)) -> Either String a

Implementation of unpinch based on GPinchable.