| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Database.InfluxDB.Decode
- class FromSeries a where
- fromSeries :: FromSeries a => Series -> Either String a
- class FromSeriesData a where
- fromSeriesData :: FromSeriesData a => SeriesData -> Either String [a]
- fromSeriesData_ :: FromSeriesData a => SeriesData -> [a]
- withValues :: (Vector Value -> ValueParser a) -> Vector Column -> Vector Value -> Parser a
- (.:) :: FromValue a => Vector Value -> Column -> ValueParser a
- (.:?) :: FromValue a => Vector Value -> Column -> ValueParser (Maybe a)
- (.!=) :: Parser (Maybe a) -> a -> Parser a
- class FromValue a where
- fromValue :: FromValue a => Value -> Either String a
- data Parser a
- data ValueParser a
- typeMismatch :: String -> Value -> Parser a
Documentation
class FromSeries a where Source #
A type that can be converted from a Series.
Minimal complete definition
Methods
parseSeries :: Series -> Parser a Source #
Instances
fromSeries :: FromSeries a => Series -> Either String a Source #
Converte a value from a Series, failing if the types do not match.
class FromSeriesData a where Source #
A type that can be converted from a SeriesData. A typical implementation
is as follows.
import Control.Applicative ((<$>), (<*>))
import qualified Data.Vector as V
data Event = Event Text EventType
data EventType = Login | Logout
instance FromSeriesData Event where
parseSeriesData = withValues $ \values -> Event
<$> values .: "user"
<*> values .: "type"
instance FromValue EventTypeMinimal complete definition
Instances
fromSeriesData :: FromSeriesData a => SeriesData -> Either String [a] Source #
Converte a value from a SeriesData, failing if the types do not match.
fromSeriesData_ :: FromSeriesData a => SeriesData -> [a] Source #
Same as fromSeriesData but ignores parse errors and returns only
successful data.
withValues :: (Vector Value -> ValueParser a) -> Vector Column -> Vector Value -> Parser a Source #
Helper function to define parseSeriesData from ValueParsers.
(.:) :: FromValue a => Vector Value -> Column -> ValueParser a Source #
Retrieve the value associated with the given column. The result is empty
if the column is not present or the value cannot be converted to the desired
type.
(.:?) :: FromValue a => Vector Value -> Column -> ValueParser (Maybe a) Source #
Retrieve the value associated with the given column. The result is
Nothing if the column is not present or the value cannot be converted to
the desired type.
(.!=) :: Parser (Maybe a) -> a -> Parser a Source #
Helper for use in combination with .:? to provide default values for
optional columns.
class FromValue a where Source #
A type that can be converted from a Value.
Minimal complete definition
Methods
parseValue :: Value -> Parser a Source #
Instances
fromValue :: FromValue a => Value -> Either String a Source #
Converte a value from a Value, failing if the types do not match.
data ValueParser a Source #
Instances