Hasql.Interpolate.Internal.Decoder

Decoding type classes

class DecodeValue a where

This type class determines which decoder we will apply to a query field by the type of the result.

Example

data ThreatLevel = None | Midnight

instance DecodeValue ThreatLevel where
  decodeValue = enum \case
    "none"     -> Just None
    "midnight" -> Just Midnight
    _          -> Nothing

Methods

decodeValue :: Value a

Instances

DecodeValue Bool

Parse a postgres bool using bool

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Bool

DecodeValue Char

Parse a postgres char using char

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Char

DecodeValue Double

Parse a postgres float8 using float8

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Double

DecodeValue Float

Parse a postgres float4 using float4

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Float

DecodeValue Int16

Parse a postgres int2 using int2

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Int16

DecodeValue Int32

Parse a postgres int4 using int4

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Int32

DecodeValue Int64

Parse a postgres int8 using int8

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Int64

DecodeValue Scientific

Parse a postgres numeric using numeric

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Scientific

DecodeValue Text

Parse a postgres text using text

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Text

DecodeValue UTCTime

Parse a postgres timestamptz using timestamptz

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value UTCTime

DecodeValue UUID

Parse a postgres uuid using uuid

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value UUID

DecodeValue Day

Parse a postgres date using date

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value Day

DecodeValue DiffTime

Parse a postgres interval using interval

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value DiffTime

DecodeValue LocalTime

Parse a postgres timestamp using timestamp

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value LocalTime

DecodeValue Json

Parse a postgres json using json

Defined in Hasql.Interpolate.Internal.Json

Methods

decodeValue :: Value Json

DecodeValue Jsonb

Parse a postgres jsonb using jsonb

Defined in Hasql.Interpolate.Internal.Json

Methods

decodeValue :: Value Jsonb

DecodeField a => DecodeValue [a]

Parse a postgres array using listArray

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value [a]

DecodeField a => DecodeValue (Vector a)

Parse a postgres array using vectorArray

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeValue :: Value (Vector a)

(Generic a, GToComposite (Rep a)) => DecodeValue (CompositeValue a)

Defined in Hasql.Interpolate.Internal.CompositeValue

Methods

decodeValue :: Value (CompositeValue a)

FromJSON a => DecodeValue (AsJsonb a)

Parse a postgres jsonb to anything that is an instance of FromJSON

Defined in Hasql.Interpolate.Internal.Json

Methods

decodeValue :: Value (AsJsonb a)

FromJSON a => DecodeValue (AsJson a)

Parse a postgres json to anything that is an instance of FromJSON

Defined in Hasql.Interpolate.Internal.Json

Methods

decodeValue :: Value (AsJson a)

class DecodeField a where

You do not need to define instances for this class; The two instances exported here cover all uses. The class only exists to lift Value to hasql's NullableOrNot GADT.

Methods

decodeField :: NullableOrNot Value a

Instances

DecodeValue a => DecodeField a

Overlappable instance for parsing non-nullable values

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeField :: NullableOrNot Value a

DecodeValue a => DecodeField (Maybe a)

Instance for parsing nullable values

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeField :: NullableOrNot Value (Maybe a)

class DecodeRow a where

Determine a row decoder from a Haskell type. Derivable with generics for any product type.

Examples

A manual instance:

data T = T Int64 Bool Text

instance DecodeRow T where
  decodeRow = T
    $ column decodeField
    * column decodeField
    * column decodeField

A generic instance:

data T
 = T Int64 Bool Text
 deriving stock (Generic)
 deriving anyclass (DecodeRow)

Minimal complete definition

Nothing

Methods

decodeRow :: Row a

default decodeRow :: (Generic a, GDecodeRow (Rep a)) => Row a

Instances

DecodeField a => DecodeRow (OneColumn a)

Parse a single column row

Defined in Hasql.Interpolate.Internal.OneColumn

Methods

decodeRow :: Row (OneColumn a)

(DecodeField x1, DecodeField x2) => DecodeRow (x1, x2)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeRow :: Row (x1, x2)

(DecodeField x1, DecodeField x2, DecodeField x3) => DecodeRow (x1, x2, x3)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeRow :: Row (x1, x2, x3)

(DecodeField x1, DecodeField x2, DecodeField x3, DecodeField x4) => DecodeRow (x1, x2, x3, x4)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeRow :: Row (x1, x2, x3, x4)

(DecodeField x1, DecodeField x2, DecodeField x3, DecodeField x4, DecodeField x5) => DecodeRow (x1, x2, x3, x4, x5)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeRow :: Row (x1, x2, x3, x4, x5)

(DecodeField x1, DecodeField x2, DecodeField x3, DecodeField x4, DecodeField x5, DecodeField x6) => DecodeRow (x1, x2, x3, x4, x5, x6)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeRow :: Row (x1, x2, x3, x4, x5, x6)

(DecodeField x1, DecodeField x2, DecodeField x3, DecodeField x4, DecodeField x5, DecodeField x6, DecodeField x7) => DecodeRow (x1, x2, x3, x4, x5, x6, x7)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeRow :: Row (x1, x2, x3, x4, x5, x6, x7)

(DecodeField x1, DecodeField x2, DecodeField x3, DecodeField x4, DecodeField x5, DecodeField x6, DecodeField x7, DecodeField x8) => DecodeRow (x1, x2, x3, x4, x5, x6, x7, x8)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeRow :: Row (x1, x2, x3, x4, x5, x6, x7, x8)

class DecodeResult a where

Determine a result decoder from a Haskell type.

Methods

decodeResult :: Result a

Instances

DecodeResult Int64

Parse the rows affected from the query result, as in an insert, update, or delete statement without a returning clause. (rowsAffected)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeResult :: Result Int64

DecodeResult ()

Ignore the query response (noResult)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeResult :: Result ()

DecodeRow a => DecodeResult [a]

Parse any number of rows into a list (rowList)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeResult :: Result [a]

DecodeRow a => DecodeResult (Maybe a)

Parse zero or one rows, throw UnexpectedAmountOfRows otherwise. (rowMaybe)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeResult :: Result (Maybe a)

DecodeRow a => DecodeResult (Vector a)

Parse any number of rows into a Vector (rowVector)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

decodeResult :: Result (Vector a)

DecodeRow a => DecodeResult (OneRow a)

Parse a single row result, throw UnexpectedAmountOfRows otherwise. (singleRow)

Defined in Hasql.Interpolate.Internal.OneRow

Methods

decodeResult :: Result (OneRow a)

Generics

class GDecodeRow a where

Methods

gdecodeRow :: Row (a p)

Instances

DecodeField a => GDecodeRow (K1 i a :: Type -> Type)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

gdecodeRow :: Row (K1 i a p)

(GDecodeRow a, GDecodeRow b) => GDecodeRow (a :*: b)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

gdecodeRow :: Row ((a :*: b) p)

GDecodeRow a => GDecodeRow (M1 t i a)

Defined in Hasql.Interpolate.Internal.Decoder

Methods

gdecodeRow :: Row (M1 t i a p)