Preql.Wire.Internal

The types in this module have invariants which cannot be checked if their constructors are in scope. Preql.Wire exports the type names only.

Documentation

newtype Query

The IsString instance does no validation; the limited instances discourage directly manipulating strings, with the high risk of SQL injection.

Constructors

Query ByteString

Instances

Show Query

Defined in Preql.Wire.Internal

Methods

showsPrec :: Int -> Query -> ShowS

show :: Query -> String

showList :: [Query] -> ShowS

IsString Query

Defined in Preql.Wire.Internal

Methods

fromString :: String -> Query

data RowDecoder a

RowDecoder is Applicative but not Monad so that we can assemble all of the OIDs before we read any of the field data sent by Postgres.

Constructors

RowDecoder [PgType] (InternalDecoder a)

Instances

Functor RowDecoder

Defined in Preql.Wire.Internal

Methods

fmap :: (a -> b) -> RowDecoder a -> RowDecoder b

(<$) :: a -> RowDecoder b -> RowDecoder a

Applicative RowDecoder

Defined in Preql.Wire.Internal

Methods

pure :: a -> RowDecoder a

(<*>) :: RowDecoder (a -> b) -> RowDecoder a -> RowDecoder b

liftA2 :: (a -> b -> c) -> RowDecoder a -> RowDecoder b -> RowDecoder c

(*>) :: RowDecoder a -> RowDecoder b -> RowDecoder b

(<*) :: RowDecoder a -> RowDecoder b -> RowDecoder a

type InternalDecoder = StateT DecoderState (ExceptT FieldError IO)

Internal because we need IO for the libpq FFI, but we promise not to do any IO besides decoding. We don't even make network calls to Postgres in InternalDecoder

data DecoderState

Constructors

DecoderState

Fields

• result :: Result
• row :: Row
• column :: Column

Instances

Eq DecoderState

Defined in Preql.Wire.Internal

Methods

(==) :: DecoderState -> DecoderState -> Bool

(/=) :: DecoderState -> DecoderState -> Bool

Show DecoderState

Defined in Preql.Wire.Internal

Methods

showsPrec :: Int -> DecoderState -> ShowS

show :: DecoderState -> String

showList :: [DecoderState] -> ShowS

decodeRow :: RowDecoder a -> Result -> Row -> ExceptT FieldError IO a

getNextValue :: InternalDecoder (Maybe ByteString)