Safe Haskell	Safe-Inferred
Language	Haskell2010

Marconi.Core.Query

Description

A set of queries that can be implemented by any indexer

See Marconi.Core for documentation.

Synopsis

data EventAtQuery event = EventAtQuery
newtype EventsMatchingQuery event = EventsMatchingQuery (event -> Maybe event)
allEvents :: EventsMatchingQuery event
newtype LatestEventsQuery event = LatestEventsQuery Word
latestEvent :: LatestEventsQuery event
newtype EventsFromQuery event = EventsFromQuery (Point event)
data Stability a
- = Stable a
- | Volatile a
isStable :: Stability a -> Bool
calcStability :: Ord point => (event -> point) -> point -> event -> Stability event
newtype WithStability query = WithStability {
- unWithStability :: query
}
withStabilityM :: (Result query ~ f event, Result (WithStability query) ~ f (Stability event), MonadError (QueryError (WithStability query)) m, Traversable f) => (event -> Stability event) -> ExceptT (QueryError query) m (f event) -> m (f (Stability event))
withStability :: forall event m indexer f. (Monad m, Ord (Point event), IsSync m event indexer, Traversable f) => indexer event -> f (Timed (Point event) event) -> m (f (Stability (Timed (Point event) event)))
withStabilityAt :: forall result m event indexer f. (Monad m, Ord (Point event), IsSync m event indexer, Applicative f) => indexer event -> Point event -> f result -> m (f (Stability result))
queryErrorWithStability :: (Result (WithStability query) ~ f (Stability event), Result query ~ f event) => (f event -> f (Stability event)) -> QueryError query -> QueryError (WithStability query)

Documentation

data EventAtQuery event #

Get the event stored by the indexer at a given point in time

Constructors

EventAtQuery

Instances

Instances details

MonadError (QueryError (EventAtQuery event)) m => AppendResult m event (EventAtQuery event) ListIndexer #
Instance details Defined in Marconi.Core.Query Methods appendResult :: Point event -> EventAtQuery event -> ListIndexer event -> m (Result (EventAtQuery event)) -> m (Result (EventAtQuery event)) #
MonadError (QueryError (EventAtQuery event)) m => Queryable m event (EventAtQuery event) ListIndexer #
Instance details Defined in Marconi.Core.Query Methods query :: Point event -> EventAtQuery event -> ListIndexer event -> m (Result (EventAtQuery event)) # queryLatest :: EventAtQuery event -> ListIndexer event -> m (Result (EventAtQuery event)) #
(MonadIO m, MonadError (QueryError (EventAtQuery event)) m) => Queryable m event (EventAtQuery event) (FileIndexer meta) #
Instance details Defined in Marconi.Core.Query Methods query :: Point event -> EventAtQuery event -> FileIndexer meta event -> m (Result (EventAtQuery event)) # queryLatest :: EventAtQuery event -> FileIndexer meta event -> m (Result (EventAtQuery event)) #
Show (EventAtQuery event) #
Instance details Defined in Marconi.Core.Query Methods showsPrec :: Int -> EventAtQuery event -> ShowS Source # show :: EventAtQuery event -> String Source # showList :: [EventAtQuery event] -> ShowS Source #
Eq (EventAtQuery event) #
Instance details Defined in Marconi.Core.Query Methods (==) :: EventAtQuery event -> EventAtQuery event -> Bool Source # (/=) :: EventAtQuery event -> EventAtQuery event -> Bool Source #
Ord (EventAtQuery event) #
Instance details Defined in Marconi.Core.Query Methods compare :: EventAtQuery event -> EventAtQuery event -> Ordering Source # (<) :: EventAtQuery event -> EventAtQuery event -> Bool Source # (<=) :: EventAtQuery event -> EventAtQuery event -> Bool Source # (>) :: EventAtQuery event -> EventAtQuery event -> Bool Source # (>=) :: EventAtQuery event -> EventAtQuery event -> Bool Source # max :: EventAtQuery event -> EventAtQuery event -> EventAtQuery event Source # min :: EventAtQuery event -> EventAtQuery event -> EventAtQuery event Source #
type Result (EventAtQuery event) #	The result of EventAtQuery is always an event. The error cases are handled by the query interface.
Instance details Defined in Marconi.Core.Query type Result (EventAtQuery event) = Maybe event

newtype EventsMatchingQuery event #

Query an indexer to find all events that match a given predicate

The result should return the most recent first

Constructors

EventsMatchingQuery (event -> Maybe event)

Instances

Instances details

MonadError (QueryError (EventsMatchingQuery event)) m => AppendResult m event (EventsMatchingQuery event) ListIndexer #
Instance details Defined in Marconi.Core.Query Methods appendResult :: Point event -> EventsMatchingQuery event -> ListIndexer event -> m (Result (EventsMatchingQuery event)) -> m (Result (EventsMatchingQuery event)) #
MonadError (QueryError (EventsMatchingQuery event)) m => Queryable m event (EventsMatchingQuery event) ListIndexer #
Instance details Defined in Marconi.Core.Query Methods query :: Point event -> EventsMatchingQuery event -> ListIndexer event -> m (Result (EventsMatchingQuery event)) # queryLatest :: EventsMatchingQuery event -> ListIndexer event -> m (Result (EventsMatchingQuery event)) #
type Result (EventsMatchingQuery event) #	The result of an `EventMatchingQuery`
Instance details Defined in Marconi.Core.Query type Result (EventsMatchingQuery event) = [Timed (Point event) event]
type Result (WithStability (EventsMatchingQuery event)) #
Instance details Defined in Marconi.Core.Query type Result (WithStability (EventsMatchingQuery event)) = [Stability (Timed (Point event) event)]

allEvents :: EventsMatchingQuery event #

Get all the events that are stored in the indexer

newtype LatestEventsQuery event #

Get the nbOfEvents last non empty events from the indexer before the point given in the query

Constructors

LatestEventsQuery Word

Instances

Instances details

MonadError (QueryError (LatestEventsQuery event)) m => Queryable m event (LatestEventsQuery event) ListIndexer #
Instance details Defined in Marconi.Core.Query Methods query :: Point event -> LatestEventsQuery event -> ListIndexer event -> m (Result (LatestEventsQuery event)) # queryLatest :: LatestEventsQuery event -> ListIndexer event -> m (Result (LatestEventsQuery event)) #
(MonadIO m, MonadError (QueryError (LatestEventsQuery event)) m) => Queryable m event (LatestEventsQuery event) (FileIndexer meta) #
Instance details Defined in Marconi.Core.Query Methods query :: Point event -> LatestEventsQuery event -> FileIndexer meta event -> m (Result (LatestEventsQuery event)) # queryLatest :: LatestEventsQuery event -> FileIndexer meta event -> m (Result (LatestEventsQuery event)) #
type Result (LatestEventsQuery event) #
Instance details Defined in Marconi.Core.Query type Result (LatestEventsQuery event) = [Timed (Point event) event]

latestEvent :: LatestEventsQuery event #

Get the latest non empty event before the point given in the query

newtype EventsFromQuery event #

Get the non empty events from the given point (excluded) to the one of the query (included)

Constructors

EventsFromQuery (Point event)

Instances

Instances details

MonadError (QueryError (EventsFromQuery event)) m => AppendResult m event (EventsFromQuery event) ListIndexer #
Instance details Defined in Marconi.Core.Query Methods appendResult :: Point event -> EventsFromQuery event -> ListIndexer event -> m (Result (EventsFromQuery event)) -> m (Result (EventsFromQuery event)) #
MonadError (QueryError (EventsFromQuery event)) m => Queryable m event (EventsFromQuery event) ListIndexer #
Instance details Defined in Marconi.Core.Query Methods query :: Point event -> EventsFromQuery event -> ListIndexer event -> m (Result (EventsFromQuery event)) # queryLatest :: EventsFromQuery event -> ListIndexer event -> m (Result (EventsFromQuery event)) #
(MonadIO m, MonadError (QueryError (EventsFromQuery event)) m) => Queryable m event (EventsFromQuery event) (FileIndexer meta) #
Instance details Defined in Marconi.Core.Query Methods query :: Point event -> EventsFromQuery event -> FileIndexer meta event -> m (Result (EventsFromQuery event)) # queryLatest :: EventsFromQuery event -> FileIndexer meta event -> m (Result (EventsFromQuery event)) #
type Result (EventsFromQuery event) #
Instance details Defined in Marconi.Core.Query type Result (EventsFromQuery event) = [Timed (Point event) event]
type Result (WithStability (EventsFromQuery event)) #
Instance details Defined in Marconi.Core.Query type Result (WithStability (EventsFromQuery event)) = [Stability (Timed (Point event) event)]

data Stability a #

Represents whether an event is considered to stable or not.

Constructors

Stable a
Volatile a

Instances

Instances details

Foldable Stability #
Instance details Defined in Marconi.Core.Query Methods fold :: Monoid m => Stability m -> m Source # foldMap :: Monoid m => (a -> m) -> Stability a -> m Source # foldMap' :: Monoid m => (a -> m) -> Stability a -> m Source # foldr :: (a -> b -> b) -> b -> Stability a -> b Source # foldr' :: (a -> b -> b) -> b -> Stability a -> b Source # foldl :: (b -> a -> b) -> b -> Stability a -> b Source # foldl' :: (b -> a -> b) -> b -> Stability a -> b Source # foldr1 :: (a -> a -> a) -> Stability a -> a Source # foldl1 :: (a -> a -> a) -> Stability a -> a Source # toList :: Stability a -> [a] Source # null :: Stability a -> Bool Source # length :: Stability a -> Int Source # elem :: Eq a => a -> Stability a -> Bool Source # maximum :: Ord a => Stability a -> a Source # minimum :: Ord a => Stability a -> a Source # sum :: Num a => Stability a -> a Source # product :: Num a => Stability a -> a Source #
Traversable Stability #
Instance details Defined in Marconi.Core.Query Methods traverse :: Applicative f => (a -> f b) -> Stability a -> f (Stability b) Source # sequenceA :: Applicative f => Stability (f a) -> f (Stability a) Source # mapM :: Monad m => (a -> m b) -> Stability a -> m (Stability b) Source # sequence :: Monad m => Stability (m a) -> m (Stability a) Source #
Functor Stability #
Instance details Defined in Marconi.Core.Query Methods fmap :: (a -> b) -> Stability a -> Stability b Source # (<$) :: a -> Stability b -> Stability a Source #
Comonad Stability #
Instance details Defined in Marconi.Core.Query Methods extract :: Stability a -> a duplicate :: Stability a -> Stability (Stability a) extend :: (Stability a -> b) -> Stability a -> Stability b
Show a => Show (Stability a) #
Instance details Defined in Marconi.Core.Query Methods showsPrec :: Int -> Stability a -> ShowS Source # show :: Stability a -> String Source # showList :: [Stability a] -> ShowS Source #
Eq a => Eq (Stability a) #
Instance details Defined in Marconi.Core.Query Methods (==) :: Stability a -> Stability a -> Bool Source # (/=) :: Stability a -> Stability a -> Bool Source #
Ord a => Ord (Stability a) #
Instance details Defined in Marconi.Core.Query Methods compare :: Stability a -> Stability a -> Ordering Source # (<) :: Stability a -> Stability a -> Bool Source # (<=) :: Stability a -> Stability a -> Bool Source # (>) :: Stability a -> Stability a -> Bool Source # (>=) :: Stability a -> Stability a -> Bool Source # max :: Stability a -> Stability a -> Stability a Source # min :: Stability a -> Stability a -> Stability a Source #

isStable :: Stability a -> Bool #

Tests for stability

calcStability :: Ord point => (event -> point) -> point -> event -> Stability event #

Helper function to wrap an event in Stability based on the last stable point and a given way to get a point.

Asks: Is the provided point less than (from a time before) or equal to (from the time of) the last stable point?

newtype WithStability query #

A wrapper representing the demand that the result of a query should come with Stability data

Constructors

WithStability
Fields unWithStability :: query

Instances

Instances details

type Result (WithStability (EventsFromQuery event)) #
Instance details Defined in Marconi.Core.Query type Result (WithStability (EventsFromQuery event)) = [Stability (Timed (Point event) event)]
type Result (WithStability (EventsMatchingQuery event)) #
Instance details Defined in Marconi.Core.Query type Result (WithStability (EventsMatchingQuery event)) = [Stability (Timed (Point event) event)]

withStabilityM #

Arguments

:: (Result query ~ f event, Result (WithStability query) ~ f (Stability event), MonadError (QueryError (WithStability query)) m, Traversable f)
=> (event -> Stability event)	A function to calculate `Stability` of an `event`
-> ExceptT (QueryError query) m (f event)	In `ExceptT` action whose result is an `event`
-> m (f (Stability event))

Convert a non-Stability supporting instance to a Stability supporting instance.

withStability #

Arguments

:: forall event m indexer f. (Monad m, Ord (Point event), IsSync m event indexer, Traversable f)
=> indexer event	An indexer
-> f (Timed (Point event) event)	A traversable of query results
-> m (f (Stability (Timed (Point event) event)))

Given an indexer and some traversable of timed query results, calculate the stability of all the query results.

withStabilityAt #

Arguments

:: forall result m event indexer f. (Monad m, Ord (Point event), IsSync m event indexer, Applicative f)
=> indexer event	An indexer
-> Point event	A specific point to compare against the last stable point
-> f result	A traversable of query results
-> m (f (Stability result))

Given an indexer, a Point and some traversable of query results, calculate the stability of all the query results.

queryErrorWithStability :: (Result (WithStability query) ~ f (Stability event), Result query ~ f event) => (f event -> f (Stability event)) -> QueryError query -> QueryError (WithStability query) #