The Combinators module defines combinators applicable to values of the `Transducer`

and `Splitter`

types defined
in the Control.Concurrent.SCC.Types module.

- splitterToMarker :: forall m x b. Monad m => Splitter m x b -> Transducer m x (Either (x, Bool) b)
- consumeBy :: forall m x y r. Monad m => Consumer m x r -> Transducer m x y
- prepend :: forall m x r. Monad m => Producer m x r -> Transducer m x x
- append :: forall m x r. Monad m => Producer m x r -> Transducer m x x
- substitute :: forall m x y r. Monad m => Producer m y r -> Transducer m x y
- class PipeableComponentPair m w c1 c2 c3 | c1 c2 -> c3, c1 c3 -> c2, c2 c3 -> c2, c1 -> m w, c2 -> m w, c3 -> m where
- class (Monad m, CompatibleSignature c1 t1 m x y, CompatibleSignature c2 t2 m x y, CompatibleSignature c3 t3 m x y) => JoinableComponentPair t1 t2 t3 m x y c1 c2 c3 | c1 c2 -> c3, c1 -> t1 m, c2 -> t2 m, c3 -> t3 m x y, t1 m x y -> c1, t2 m x y -> c2, t3 m x y -> c3 where
- sNot :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- sAnd :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (b1, b2)
- sOr :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (Either b1 b2)
- pAnd :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (b1, b2)
- pOr :: forall c m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (Either b1 b2)
- ifs :: forall c m x b. (MonadParallel m, Branching c m x ()) => Bool -> Splitter m x b -> c -> c -> c
- wherever :: forall m x b. MonadParallel m => Bool -> Transducer m x x -> Splitter m x b -> Transducer m x x
- unless :: forall m x b. MonadParallel m => Bool -> Transducer m x x -> Splitter m x b -> Transducer m x x
- select :: forall m x b. Monad m => Splitter m x b -> Transducer m x x
- while :: forall m x b. MonadParallel m => [(Bool, (Transducer m x x, Splitter m x b))] -> Transducer m x x
- nestedIn :: forall m x b. MonadParallel m => [(Bool, (Splitter m x b, Splitter m x b))] -> Splitter m x b
- foreach :: forall m x b c. (MonadParallel m, Branching c m x ()) => Bool -> Splitter m x b -> c -> c -> c
- having :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x b1
- havingOnly :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x b1
- followedBy :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (b1, b2)
- even :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- first :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- uptoFirst :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- prefix :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- last :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- lastAndAfter :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- suffix :: forall m x b. Monad m => Splitter m x b -> Splitter m x b
- startOf :: forall m x b. Monad m => Splitter m x b -> Splitter m x (Maybe b)
- endOf :: forall m x b. Monad m => Splitter m x b -> Splitter m x (Maybe b)
- between :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x b1
- parseRegions :: forall m x b. Monad m => Splitter m x b -> Parser m x b
- parseNestedRegions :: forall m x b. Monad m => Splitter m x (Boundary b) -> Parser m x b
- groupMarks :: (Monad m, AncestorFunctor a d, AncestorFunctor a (SinkFunctor d x)) => Source m a (Either (x, Bool) b) -> (Maybe (Maybe b) -> Source m (SourceFunctor d x) x -> Coroutine (SourceFunctor d x) m r) -> Coroutine d m ()
- findsTrueIn :: forall m a d x b. (Monad m, AncestorFunctor a d) => Splitter m x b -> Source m a x -> Coroutine d m (Maybe (Maybe b))
- findsFalseIn :: forall m a d x b. (Monad m, AncestorFunctor a d) => Splitter m x b -> Source m a x -> Coroutine d m Bool
- teeConsumers :: forall m a d x r1 r2. MonadParallel m => Bool -> (forall a. OpenConsumer m a (SinkFunctor d x) x r1) -> (forall a. OpenConsumer m a (SourceFunctor d x) x r2) -> OpenConsumer m a d x (r1, r2)

# Consumer, producer, and transducer combinators

splitterToMarker :: forall m x b. Monad m => Splitter m x b -> Transducer m x (Either (x, Bool) b)Source

consumeBy :: forall m x y r. Monad m => Consumer m x r -> Transducer m x ySource

Converts a `Consumer`

into a `Transducer`

with no output.

prepend :: forall m x r. Monad m => Producer m x r -> Transducer m x xSource

Combinator `prepend`

converts the given producer to a `Transducer`

that passes all its
input through unmodified, except for prepending the output of the argument producer to it. The following law holds: ```
```

`prepend`

*prefix* = `join`

(`substitute`

*prefix*) `id`

append :: forall m x r. Monad m => Producer m x r -> Transducer m x xSource

Combinator `append`

converts the given producer to a `Transducer`

that passes all its
input through unmodified, finally appending the output of the argument producer to it. The following law holds: ```
```

`append`

*suffix* = `join`

`id`

(`substitute`

*suffix*)

substitute :: forall m x y r. Monad m => Producer m y r -> Transducer m x ySource

The `substitute`

combinator converts its argument producer to a `Transducer`

that
produces the same output, while consuming its entire input and ignoring it.

class PipeableComponentPair m w c1 c2 c3 | c1 c2 -> c3, c1 c3 -> c2, c2 c3 -> c2, c1 -> m w, c2 -> m w, c3 -> m whereSource

Class `PipeableComponentPair`

applies to any two components that can be combined into a third component with the
following properties:

- The input of the result, if any, becomes the input of the first component.
- The output produced by the first child component is consumed by the second child component.
- The result output, if any, is the output of the second component.

MonadParallel m => PipeableComponentPair m x (Producer m x ()) (Consumer m x ()) (Performer m ()) | |

MonadParallel m => PipeableComponentPair m y (Transducer m x y) (Transducer m y z) (Transducer m x z) | |

MonadParallel m => PipeableComponentPair m x (Producer m x r) (Transducer m x y) (Producer m y r) | |

MonadParallel m => PipeableComponentPair m y (Transducer m x y) (Consumer m y r) (Consumer m x r) |

class (Monad m, CompatibleSignature c1 t1 m x y, CompatibleSignature c2 t2 m x y, CompatibleSignature c3 t3 m x y) => JoinableComponentPair t1 t2 t3 m x y c1 c2 c3 | c1 c2 -> c3, c1 -> t1 m, c2 -> t2 m, c3 -> t3 m x y, t1 m x y -> c1, t2 m x y -> c2, t3 m x y -> c3 whereSource

Class `JoinableComponentPair`

applies to any two components that can be combined into a third component with the
following properties:

- if both argument components consume input, the input of the combined component gets distributed to both components in parallel,
- if both argument components produce output, the output of the combined component is a concatenation of the complete output from the first component followed by the complete output of the second component, and
- the
`join`

method may apply the components in any order, the`sequence`

method makes sure its first argument has completed before using the second one.

MonadParallel m => JoinableComponentPair TransducerType TransducerType TransducerType m [x] [y] (Transducer m x y) (Transducer m x y) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair TransducerType (PerformerType r) TransducerType m [x] [y] (Transducer m x y) (Performer m r) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair TransducerType (ProducerType ()) TransducerType m [x] [y] (Transducer m x y) (Producer m y ()) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair TransducerType (ConsumerType ()) TransducerType m [x] [y] (Transducer m x y) (Consumer m x ()) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair (PerformerType r) TransducerType TransducerType m [x] [y] (Performer m r) (Transducer m x y) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair (ProducerType ()) TransducerType TransducerType m [x] [y] (Producer m y ()) (Transducer m x y) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair (ConsumerType ()) TransducerType TransducerType m [x] [y] (Consumer m x ()) (Transducer m x y) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair (ProducerType ()) (ConsumerType ()) TransducerType m [x] [y] (Producer m y ()) (Consumer m x ()) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair (ConsumerType ()) (ProducerType ()) TransducerType m [x] [y] (Consumer m x ()) (Producer m y ()) (Transducer m x y) | |

MonadParallel m => JoinableComponentPair (PerformerType r1) (PerformerType r2) (PerformerType r2) m () () (Performer m r1) (Performer m r2) (Performer m r2) | |

MonadParallel m => JoinableComponentPair (PerformerType r1) (ProducerType r2) (ProducerType r2) m () [x] (Performer m r1) (Producer m x r2) (Producer m x r2) | |

MonadParallel m => JoinableComponentPair (ProducerType r1) (PerformerType r2) (ProducerType r2) m () [x] (Producer m x r1) (Performer m r2) (Producer m x r2) | |

Monad m => JoinableComponentPair (ProducerType r1) (ProducerType r2) (ProducerType r2) m () [x] (Producer m x r1) (Producer m x r2) (Producer m x r2) | |

MonadParallel m => JoinableComponentPair (PerformerType r1) (ConsumerType r2) (ConsumerType r2) m [x] () (Performer m r1) (Consumer m x r2) (Consumer m x r2) | |

MonadParallel m => JoinableComponentPair (ConsumerType r1) (PerformerType r2) (ConsumerType r2) m [x] () (Consumer m x r1) (Performer m r2) (Consumer m x r2) | |

MonadParallel m => JoinableComponentPair (ConsumerType ()) (ConsumerType ()) (ConsumerType ()) m [x] () (Consumer m x ()) (Consumer m x ()) (Consumer m x ()) |

# Pseudo-logic splitter combinators

Combinators `sAnd`

and `sOr`

are only *pseudo*-logic. While the laws of double negation and De Morgan's laws
hold, `sAnd`

and `sOr`

are in general not commutative, associative, nor idempotent. In the special case when all
argument splitters are stateless, such as those produced by `statelessSplitter`

,
these combinators do satisfy all laws of Boolean algebra.

sNot :: forall m x b. Monad m => Splitter m x b -> Splitter m x bSource

The `sNot`

(streaming not) combinator simply reverses the outputs of the argument splitter. In other words, data
that the argument splitter sends to its *true* sink goes to the *false* sink of the result, and vice versa.

sAnd :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (b1, b2)Source

The `sAnd`

combinator sends the *true* sink output of its left operand to the input of its right operand for
further splitting. Both operands' *false* sinks are connected to the *false* sink of the combined splitter, but any
input value to reach the *true* sink of the combined component data must be deemed true by both splitters.

sOr :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (Either b1 b2)Source

A `sOr`

combinator's input value can reach its *false* sink only by going through both argument splitters' *false*
sinks.

## Zipping logic combinators

The `pAnd`

and `pOr`

combinators run the argument splitters in parallel and combine their logical outputs using
the corresponding logical operation on each output pair, in a manner similar to `zipWith`

. They fully
satisfy the laws of Boolean algebra.

pAnd :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (b1, b2)Source

Combinator `pAnd`

is a pairwise logical conjunction of two splitters run in parallel on the same input.

pOr :: forall c m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (Either b1 b2)Source

Combinator `pOr`

is a pairwise logical disjunction of two splitters run in parallel on the same input.

# Flow-control combinators

The following combinators resemble the common flow-control programming language constructs. Combinators
`wherever`

, `unless`

, and `select`

are just the special cases of the combinator `ifs`

.

ifs :: forall c m x b. (MonadParallel m, Branching c m x ()) => Bool -> Splitter m x b -> c -> c -> cSource

wherever :: forall m x b. MonadParallel m => Bool -> Transducer m x x -> Splitter m x b -> Transducer m x xSource

unless :: forall m x b. MonadParallel m => Bool -> Transducer m x x -> Splitter m x b -> Transducer m x xSource

select :: forall m x b. Monad m => Splitter m x b -> Transducer m x xSource

## Recursive

while :: forall m x b. MonadParallel m => [(Bool, (Transducer m x x, Splitter m x b))] -> Transducer m x xSource

The recursive combinator `while`

feeds the true sink of the argument splitter back to itself, modified by the
argument transducer. Data fed to the splitter's false sink is passed on unmodified.

nestedIn :: forall m x b. MonadParallel m => [(Bool, (Splitter m x b, Splitter m x b))] -> Splitter m x bSource

The recursive combinator `nestedIn`

combines two splitters into a mutually recursive loop acting as a single
splitter. The true sink of one of the argument splitters and false sink of the other become the true and false sinks
of the loop. The other two sinks are bound to the other splitter's source. The use of `nestedIn`

makes sense only
on hierarchically structured streams. If we gave it some input containing a flat sequence of values, and assuming
both component splitters are deterministic and stateless, an input value would either not loop at all or it would
loop forever.

# Section-based combinators

All combinators in this section use their `Control.Concurrent.SCC.Splitter`

argument to determine the structure
of the input. Every contiguous portion of the input that gets passed to one or the other sink of the splitter is
treated as one section in the logical structure of the input stream. What is done with the section depends on the
combinator, but the sections, and therefore the logical structure of the input stream, are determined by the
argument splitter alone.

foreach :: forall m x b c. (MonadParallel m, Branching c m x ()) => Bool -> Splitter m x b -> c -> c -> cSource

The `foreach`

combinator is similar to the combinator `ifs`

in that it combines a splitter and two transducers into
another transducer. However, in this case the transducers are re-instantiated for each consecutive portion of the
input as the splitter chunks it up. Each contiguous portion of the input that the splitter sends to one of its two
sinks gets transducered through the appropriate argument transducer as that transducer's whole input. As soon as the
contiguous portion is finished, the transducer gets terminated.

having :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x b1Source

The `having`

combinator combines two pure splitters into a pure splitter. One splitter is used to chunk the input
into contiguous portions. Its *false* sink is routed directly to the *false* sink of the combined splitter. The
second splitter is instantiated and run on each portion of the input that goes to first splitter's *true* sink. If
the second splitter sends any output at all to its *true* sink, the whole input portion is passed on to the *true*
sink of the combined splitter, otherwise it goes to its *false* sink.

havingOnly :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x b1Source

The `havingOnly`

combinator is analogous to the `having`

combinator, but it succeeds and passes each chunk of the
input to its *true* sink only if the second splitter sends no part of it to its *false* sink.

followedBy :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x (b1, b2)Source

Combinator `followedBy`

treats its argument `Splitter`

s as patterns components and returns a `Splitter`

that
matches their concatenation. A section of input is considered *true* by the result iff its prefix is considered
*true* by argument *s1* and the rest of the section is considered *true* by *s2*. The splitter *s2* is started anew
after every section split to *true* sink by *s1*.

## first and its variants

first :: forall m x b. Monad m => Splitter m x b -> Splitter m x bSource

The result of combinator `first`

behaves the same as the argument splitter up to and including the first portion of
the input which goes into the argument's *true* sink. All input following the first true portion goes into the
*false* sink.

uptoFirst :: forall m x b. Monad m => Splitter m x b -> Splitter m x bSource

The result of combinator `uptoFirst`

takes all input up to and including the first portion of the input which goes
into the argument's *true* sink and feeds it to the result splitter's *true* sink. All the rest of the input goes
into the *false* sink. The only difference between `first`

and `uptoFirst`

combinators is in where they direct the
*false* portion of the input preceding the first *true* part.

prefix :: forall m x b. Monad m => Splitter m x b -> Splitter m x bSource

The `prefix`

combinator feeds its *true* sink only the prefix of the input that its argument feeds to its *true*
sink. All the rest of the input is dumped into the *false* sink of the result.

## last and its variants

last :: forall m x b. Monad m => Splitter m x b -> Splitter m x bSource

The result of the combinator `last`

is a splitter which directs all input to its *false* sink, up to the last
portion of the input which goes to its argument's *true* sink. That portion of the input is the only one that goes to
the resulting component's *true* sink. The splitter returned by the combinator `last`

has to buffer the previous two
portions of its input, because it cannot know if a true portion of the input is the last one until it sees the end of
the input or another portion succeeding the previous one.

lastAndAfter :: forall m x b. Monad m => Splitter m x b -> Splitter m x bSource

The result of the combinator `lastAndAfter`

is a splitter which directs all input to its *false* sink, up to the
last portion of the input which goes to its argument's *true* sink. That portion and the remainder of the input is
fed to the resulting component's *true* sink. The difference between `last`

and `lastAndAfter`

combinators is where
they feed the *false* portion of the input, if any, remaining after the last *true* part.

suffix :: forall m x b. Monad m => Splitter m x b -> Splitter m x bSource

The `suffix`

combinator feeds its *true* sink only the suffix of the input that its argument feeds to its *true*
sink. All the rest of the input is dumped into the *false* sink of the result.

## positional splitters

startOf :: forall m x b. Monad m => Splitter m x b -> Splitter m x (Maybe b)Source

Splitter `startOf`

issues an empty *true* section at the beginning of every section considered *true* by its
argument splitter, otherwise the entire input goes into its *false* sink.

endOf :: forall m x b. Monad m => Splitter m x b -> Splitter m x (Maybe b)Source

Splitter `endOf`

issues an empty *true* section at the end of every section considered *true* by its argument
splitter, otherwise the entire input goes into its *false* sink.

## input ranges

between :: forall m x b1 b2. MonadParallel m => Bool -> Splitter m x b1 -> Splitter m x b2 -> Splitter m x b1Source

Combinator `...`

tracks the running balance of difference between the number of preceding starts of sections
considered *true* according to its first argument and the ones according to its second argument. The combinator
passes to *true* all input values for which the difference balance is positive. This combinator is typically used
with `startOf`

and `endOf`

in order to count entire input sections and ignore their lengths.

# parser support

parseRegions :: forall m x b. Monad m => Splitter m x b -> Parser m x bSource

Converts a splitter into a parser.

parseNestedRegions :: forall m x b. Monad m => Splitter m x (Boundary b) -> Parser m x bSource

Converts a boundary-marking splitter into a parser.

# helper functions

groupMarks :: (Monad m, AncestorFunctor a d, AncestorFunctor a (SinkFunctor d x)) => Source m a (Either (x, Bool) b) -> (Maybe (Maybe b) -> Source m (SourceFunctor d x) x -> Coroutine (SourceFunctor d x) m r) -> Coroutine d m ()Source

Runs the second argument on every contiguous region of input source (typically produced by `splitterToMarker`

)
whose all values either match `Left (_, True)`

or `Left (_, False)`

.

findsTrueIn :: forall m a d x b. (Monad m, AncestorFunctor a d) => Splitter m x b -> Source m a x -> Coroutine d m (Maybe (Maybe b))Source

findsFalseIn :: forall m a d x b. (Monad m, AncestorFunctor a d) => Splitter m x b -> Source m a x -> Coroutine d m BoolSource

teeConsumers :: forall m a d x r1 r2. MonadParallel m => Bool -> (forall a. OpenConsumer m a (SinkFunctor d x) x r1) -> (forall a. OpenConsumer m a (SourceFunctor d x) x r2) -> OpenConsumer m a d x (r1, r2)Source