Copyright	(c) George Ungureanu 2015-2016
License	BSD-style (see the file LICENSE)
Maintainer	ugeorge@kth.se
Stability	experimental
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

ForSyDe.Atom.MoC.Stream

Description

This module defines the shallow-embedded Stream data type and utility functions operating on it. In ForSyDe a signal is represented as a (partially or totally) ordered sequence of events that enables processes to communicate and synchronize. In ForSyDe-Atom signals are the main operating type for the MoC layer. The Stream type is only the base (potentially infinite) structure which can encapsulate events in order to describe signals.

Synopsis

data Stream e
- = NullS
- | e :- (Stream e)
stream :: [a] -> Stream a
fromStream :: Stream a -> [a]
headS :: Stream a -> a
tailS :: Stream e -> Stream e
lastS :: Stream p -> p
repeatS :: a -> Stream a
takeS :: (Num t, Ord t) => t -> Stream e -> Stream e
dropS :: (Num t, Ord t) => t -> Stream e -> Stream e
takeWhileS :: (a -> Bool) -> Stream a -> Stream a
(+-+) :: Stream e -> Stream e -> Stream e

Documentation

data Stream e Source #

Defines a stream of events, encapsulating them in a structure isomorphic to an infinite list [Bird87], thus all properties of lists may also be applied to Streams. While, in combination with lazy evaluation, it is possible to create and simulate infinite signals, we need to ensure that the first/previous event is always fully evaluated, which is equivalent to ensuring the the monotonicity property in dataflow systems. This translates in the following composition rule:

non-causal feedback is forbidden: also called "zero-delay" feedback loops, are caused by un-evaluated self-referential calls. In a feedback loop, there always has to be enough events to ensure the data flow.

This rule imposes that the stream of data is uninterrupted in order to have an evaluatable kernel every time a new event is produced (i.e. to avoid deadlocks), which is ther equivalent to ensuring continuity in dataflow systems. This translates in the following rule:

cleaning of signals in a feedback is forbidden: in other words, whenever a feedback composition occurs, for each new input at any instant in time, a process must react with at least one output event.

Constructors

NullS	terminates a signal
e :- (Stream e) infixr 3	the default constructor appends an event to the head of the stream

Instances

Instances details

Functor Stream Source #	allows for the mapping of an arbitrary function `(a -> b)` upon all the events of a `(Stream a)`.
Instance details Defined in ForSyDe.Atom.MoC.Stream Methods fmap :: (a -> b) -> Stream a -> Stream b # (<$) :: a -> Stream b -> Stream a #
Applicative Stream Source #	enables the `Stream` to behave like a `ZipList`
Instance details Defined in ForSyDe.Atom.MoC.Stream Methods pure :: a -> Stream a # (<>) :: Stream (a -> b) -> Stream a -> Stream b # liftA2 :: (a -> b -> c) -> Stream a -> Stream b -> Stream c # (>) :: Stream a -> Stream b -> Stream b # (<*) :: Stream a -> Stream b -> Stream a #
Foldable Stream Source #	provides folding functions useful for implementing utilities, such as `length`.
Instance details Defined in ForSyDe.Atom.MoC.Stream Methods fold :: Monoid m => Stream m -> m # foldMap :: Monoid m => (a -> m) -> Stream a -> m # foldMap' :: Monoid m => (a -> m) -> Stream a -> m # foldr :: (a -> b -> b) -> b -> Stream a -> b # foldr' :: (a -> b -> b) -> b -> Stream a -> b # foldl :: (b -> a -> b) -> b -> Stream a -> b # foldl' :: (b -> a -> b) -> b -> Stream a -> b # foldr1 :: (a -> a -> a) -> Stream a -> a # foldl1 :: (a -> a -> a) -> Stream a -> a # toList :: Stream a -> [a] # null :: Stream a -> Bool # length :: Stream a -> Int # elem :: Eq a => a -> Stream a -> Bool # maximum :: Ord a => Stream a -> a # minimum :: Ord a => Stream a -> a # sum :: Num a => Stream a -> a # product :: Num a => Stream a -> a #
Read a => Read (Stream a) Source #	signal `(1 :- 2 :- NullS)` is read using the string `"{1,2}"`.
Instance details Defined in ForSyDe.Atom.MoC.Stream Methods readsPrec :: Int -> ReadS (Stream a) # readList :: ReadS [Stream a] # readPrec :: ReadPrec (Stream a) # readListPrec :: ReadPrec [Stream a] #
Show a => Show (Stream a) Source #	signal `(1 :- 2 :- NullS)` is represented as `{1,2}`.
Instance details Defined in ForSyDe.Atom.MoC.Stream Methods showsPrec :: Int -> Stream a -> ShowS # show :: Stream a -> String # showList :: [Stream a] -> ShowS #
Plottable a => Plot (Signal a) Source #	`SY` signals.
Instance details Defined in ForSyDe.Atom.Utility.Plot Methods sample :: Float -> Signal a -> Samples Source # sample' :: Signal a -> Samples Source # takeUntil :: Float -> Signal a -> Signal a Source # getInfo :: Signal a -> PInfo Source #
Plottable a => Plot (Signal a) Source #	For plotting `SDF` signals.
Instance details Defined in ForSyDe.Atom.Utility.Plot Methods sample :: Float -> Signal a -> Samples Source # sample' :: Signal a -> Samples Source # takeUntil :: Float -> Signal a -> Signal a Source # getInfo :: Signal a -> PInfo Source #
Plottable a => Plot (Signal a) Source #	For plotting `CT` signals.
Instance details Defined in ForSyDe.Atom.Utility.Plot Methods sample :: Float -> Signal a -> Samples Source # sample' :: Signal a -> Samples Source # takeUntil :: Float -> Signal a -> Signal a Source # getInfo :: Signal a -> PInfo Source #
(Plottable a, Show t, Real t, Fractional t, Num t, Ord t, Eq t) => Plot (SignalBase t a) Source #	For plotting `RE` signals.
Instance details Defined in ForSyDe.Atom.Utility.Plot Methods sample :: Float -> SignalBase t a -> Samples Source # sample' :: SignalBase t a -> Samples Source # takeUntil :: Float -> SignalBase t a -> SignalBase t a Source # getInfo :: SignalBase t a -> PInfo Source #
(Plottable a, Show t, Real t, Fractional t, Num t, Ord t, Eq t) => Plot (SignalBase t a) Source #	For plotting `DE` signals.
Instance details Defined in ForSyDe.Atom.Utility.Plot Methods sample :: Float -> SignalBase t a -> Samples Source # sample' :: SignalBase t a -> Samples Source # takeUntil :: Float -> SignalBase t a -> SignalBase t a Source # getInfo :: SignalBase t a -> PInfo Source #