Portability | Haskell 98 |
---|---|

Stability | stable |

Maintainer | haskell@henning-thielemann.de |

Event lists starting with a time difference and ending with a body.

The time is stored in differences between the events. Thus there is no increase of time information for long, or even infinite, streams of events. Further on, the time difference is stored in the latter of two neighbouring events. This is necessary for real-time computing where it is not known whether and when the next event happens.

- data T time body
- empty :: T time body
- singleton :: time -> body -> T time body
- null :: T time body -> Bool
- viewL :: T time body -> Maybe ((time, body), T time body)
- viewR :: T time body -> Maybe (T time body, (time, body))
- cons :: time -> body -> T time body -> T time body
- snoc :: T time body -> time -> body -> T time body
- fromPairList :: [(a, b)] -> T a b
- toPairList :: T a b -> [(a, b)]
- getTimes :: T time body -> [time]
- getBodies :: T time body -> [body]
- duration :: Num time => T time body -> time
- mapBody :: (body0 -> body1) -> T time body0 -> T time body1
- mapTime :: (time0 -> time1) -> T time0 body -> T time1 body
- mapM :: Monad m => (time0 -> m time1) -> (body0 -> m body1) -> T time0 body0 -> m (T time1 body1)
- mapM_ :: Monad m => (time -> m ()) -> (body -> m ()) -> T time body -> m ()
- mapBodyM :: Monad m => (body0 -> m body1) -> T time body0 -> m (T time body1)
- mapTimeM :: Monad m => (time0 -> m time1) -> T time0 body -> m (T time1 body)
- foldr :: (time -> a -> b) -> (body -> b -> a) -> b -> T time body -> b
- foldrPair :: (time -> body -> a -> a) -> a -> T time body -> a
- merge :: (C time, Ord body) => T time body -> T time body -> T time body
- mergeBy :: C time => (body -> body -> Bool) -> T time body -> T time body -> T time body
- insert :: (C time, Ord body) => time -> body -> T time body -> T time body
- insertBy :: (C time, Ord body) => (body -> body -> Bool) -> time -> body -> T time body -> T time body
- moveForward :: C time => T time (time, body) -> T time body
- decreaseStart :: C time => time -> T time body -> T time body
- delay :: C time => time -> T time body -> T time body
- filter :: Num time => (body -> Bool) -> T time body -> T time body
- partition :: Num time => (body -> Bool) -> T time body -> (T time body, T time body)
- slice :: (Eq a, Num time) => (body -> a) -> T time body -> [(a, T time body)]
- span :: (body -> Bool) -> T time body -> (T time body, T time body)
- mapMaybe :: Num time => (body0 -> Maybe body1) -> T time body0 -> T time body1
- catMaybes :: Num time => T time (Maybe body) -> T time body
- normalize :: (C time, Ord body) => T time body -> T time body
- isNormalized :: (C time, Ord body) => T time body -> Bool
- collectCoincident :: C time => T time body -> T time [body]
- flatten :: C time => T time [body] -> T time body
- mapCoincident :: C time => ([a] -> [b]) -> T time a -> T time b
- append :: T time body -> T time body -> T time body
- concat :: [T time body] -> T time body
- cycle :: T time body -> T time body
- discretize :: (C time, RealFrac time, C i, Integral i) => T time body -> T i body
- resample :: (C time, RealFrac time, C i, Integral i) => time -> T time body -> T i body
- toAbsoluteEventList :: Num time => time -> T time body -> T time body
- fromAbsoluteEventList :: Num time => T time body -> T time body

# Documentation

fromPairList :: [(a, b)] -> T a bSource

toPairList :: T a b -> [(a, b)]Source

mapM :: Monad m => (time0 -> m time1) -> (body0 -> m body1) -> T time0 body0 -> m (T time1 body1)Source

merge :: (C time, Ord body) => T time body -> T time body -> T time bodySource

This function merges the events of two lists into a new event list.
Note that `merge`

compares entire events rather than just start times.
This is to ensure that it is commutative,
one of the properties we test for.

insert :: (C time, Ord body) => time -> body -> T time body -> T time bodySource

`insert`

inserts an event into an event list at the given time.

insertBy :: (C time, Ord body) => (body -> body -> Bool) -> time -> body -> T time body -> T time bodySource

moveForward :: C time => T time (time, body) -> T time bodySource

Move events towards the front of the event list. You must make sure, that no event is moved before time zero. This works only for finite lists.

decreaseStart :: C time => time -> T time body -> T time bodySource

filter :: Num time => (body -> Bool) -> T time body -> T time bodySource

Keep only events that match a predicate while preserving absolute times.

slice :: (Eq a, Num time) => (body -> a) -> T time body -> [(a, T time body)]Source

Using a classification function we splice the event list into lists, each containing the same class. Absolute time stamps are preserved.

collectCoincident :: C time => T time body -> T time [body]Source

Group events that have equal start times (that is zero time differences).

flatten :: C time => T time [body] -> T time bodySource

Reverse to collectCoincident:
Turn each `body`

into a separate event.

xs == flatten (collectCoincident xs)

mapCoincident :: C time => ([a] -> [b]) -> T time a -> T time bSource

Apply a function to the lists of coincident events.

discretize :: (C time, RealFrac time, C i, Integral i) => T time body -> T i bodySource

We provide `discretize`

and `resample`

for discretizing the time information.
When converting the precise relative event times
to the integer relative event times
we have to prevent accumulation of rounding errors.
We avoid this problem with a stateful conversion
which remembers each rounding error we make.
This rounding error is used to correct the next rounding.
Given the relative time and duration of an event
the function `floorDiff`

creates a `Control.Monad.State.State`

which computes the rounded relative time.
It is corrected by previous rounding errors.

The resulting event list may have differing time differences which were equal before discretization, but the overall timing is uniformly close to the original.

We use `floorDiff`

rather than `roundDiff`

in order to compute exclusively with non-negative numbers.

toAbsoluteEventList :: Num time => time -> T time body -> T time bodySource

We tried hard to compute everything with respect to relative times. However sometimes we need absolute time values.

fromAbsoluteEventList :: Num time => T time body -> T time bodySource