Database.PostgreSQL.Store.Result

Result processor

data ResultError

Error that occured during result processing

Constructors

TooFewColumnsError Column

Occurs when you're trying to access a column that does not exist.

UnpackError Row Column Oid Format

The value at a given row and column could not be unpacked.

Instances

Eq ResultError

Methods

(==) :: ResultError -> ResultError -> Bool

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

Show ResultError

Methods

showsPrec :: Int -> ResultError -> ShowS

show :: ResultError -> String

showList :: [ResultError] -> ShowS

MonadError ResultError ResultProcessor

Methods

throwError :: ResultError -> ResultProcessor a

catchError :: ResultProcessor a -> (ResultError -> ResultProcessor a) -> ResultProcessor a

data ResultProcessor a

Result processor

Instances

Monad ResultProcessor

Methods

(>>=) :: ResultProcessor a -> (a -> ResultProcessor b) -> ResultProcessor b

(>>) :: ResultProcessor a -> ResultProcessor b -> ResultProcessor b

return :: a -> ResultProcessor a

fail :: String -> ResultProcessor a

Functor ResultProcessor

Methods

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

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

Applicative ResultProcessor

Methods

pure :: a -> ResultProcessor a

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

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

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

MonadIO ResultProcessor

Methods

liftIO :: IO a -> ResultProcessor a

MonadError ResultError ResultProcessor

Methods

throwError :: ResultError -> ResultProcessor a

catchError :: ResultProcessor a -> (ResultError -> ResultProcessor a) -> ResultProcessor a

processResult :: Result -> ResultProcessor a -> ExceptT ResultError IO [a]

Process the entire result set.

processOneResult :: Result -> ResultProcessor a -> ExceptT ResultError IO (Maybe a)

Process one row of the result set.

skipColumn :: ResultProcessor ()

Move cursor to the next column.

unpackColumn :: Column a => ResultProcessor a

Unpack the current column and move the cursor to the next column.