FlowStreamUnion

Represents a cold stream of values that requires an environment, can fail with a typed error, and supports backpressure.

Specification

Kind

Union

Members

Examples

unfoldFlowSignature

FlowStream.unfoldFlow step initialState

fromSeqSignature

FlowStream.fromSeq values

emptySignature

FlowStream.empty

singletonSignature

FlowStream.singleton value

fromFlowSignature

FlowStream.fromFlow flow

Summary

Name	Signature	Synopsis
Union cases
FlowStream	FlowStream 'env -> CancellationToken -> Execution, 'error>	No description available.
Operations
unfoldFlow	FlowStream.unfoldFlow step initialState	Creates a cold stream by repeatedly running an effectful state transition.
fromSeq	FlowStream.fromSeq values	Creates a stream from a synchronous sequence of values.
empty	FlowStream.empty	Creates an empty stream.
singleton	FlowStream.singleton value	Creates a stream containing one value.
fromFlow	FlowStream.fromFlow flow	Creates a one-element stream from an effectful value.
runForEach	FlowStream.runForEach action (FlowStream op)	Executes the stream and performs a synchronous action for each successful value.
map	FlowStream.map f (FlowStream op)	Transforms the successful values of a stream using the provided function.
mapError	FlowStream.mapError mapper (FlowStream op)	Transforms the typed error channel of a stream.
filter	FlowStream.filter predicate (FlowStream op)	Keeps values that satisfy a predicate.
choose	FlowStream.choose chooser (FlowStream op)	Maps and filters values in one operation.
tapFlow	FlowStream.tapFlow action (FlowStream op)	Runs an effect for each value before emitting the original value.
mapFlow	FlowStream.mapFlow mapper (FlowStream op)	Transforms every value with a Flow effect.
take	FlowStream.take count (FlowStream op)	Emits at most count values.
skip	FlowStream.skip count (FlowStream op)	Skips the first count values.
takeWhile	FlowStream.takeWhile predicate (FlowStream op)	Emits values while a predicate remains true.
skipWhile	FlowStream.skipWhile predicate (FlowStream op)	Skips values while a predicate remains true.
indexed	FlowStream.indexed (FlowStream op)	Emits each value paired with its zero-based index.
scan	FlowStream.scan folder initial (FlowStream op)	Emits successive accumulator states.
distinctUntilChangedBy	FlowStream.distinctUntilChangedBy projection (FlowStream op)	Suppresses consecutive duplicate values according to a projection.
append	FlowStream.append (FlowStream right) (FlowStream left)	Concatenates two streams, evaluating the second only after the first ends.
collect	FlowStream.collect mapper (FlowStream outer)	Maps each value to a stream and concatenates the resulting streams.
zip	FlowStream.zip (FlowStream right) (FlowStream left)	Pairs values from two streams until either stream ends.
runFold	FlowStream.runFold folder initial (FlowStream op)	Folds a stream into one value inside Flow.
runCollect	FlowStream.runCollect stream	Collects all emitted values into a list.
runDrain	FlowStream.runDrain stream	Consumes a stream and ignores its values.
runForEachFlow	FlowStream.runForEachFlow action (FlowStream op)	Runs an effectful action for every stream value.

Union cases

kind:member

FlowStream

FlowStream 'env -> CancellationToken -> Execution<StreamStep<'value, 'error>, 'error>

Member

Parameters

Name	Type	Description
Item	'env -> CancellationToken -> Execution<StreamStep<'value, 'error>, 'error>

Returns

unit

Operations

kind:member

unfoldFlow

FlowStream.unfoldFlow step initialState

Member

Creates a cold stream by repeatedly running an effectful state transition.

Parameters

Name	Type	Description
step	'state -> Flow<'env, 'error, ('value * 'state) option>	Returns `Some(value, nextState)` or `None` when the stream is complete.
initialState	'state	The state used for the first pull.

Returns

FlowStream<'env, 'error, 'value>

Verification Examples

FlowStream.unfoldFlow (fun n -> Flow.ok (if n < 3 then Some(n, n + 1) else None)) 0

kind:member

fromSeq

FlowStream.fromSeq values

Member

Creates a stream from a synchronous sequence of values.

Parameters

Name	Type	Description
values	'value seq	The sequence of values to be emitted by the stream.

Returns

FlowStream<'env, 'error, 'value>

Verification Examples

FlowStream.fromSeq [1..10]
|> FlowStream.runCollect
|> Flow.run ()

kind:member

empty

FlowStream.empty

Member

Creates an empty stream.

Returns

FlowStream<'env, 'error, 'value>

Verification Examples

FlowStream.empty<unit, string, int>

kind:member

singleton

FlowStream.singleton value

Member

Creates a stream containing one value.

Parameters

Name	Type	Description
value	'value

Returns

FlowStream<'env, 'error, 'value>

Verification Examples

FlowStream.singleton 42

kind:member

fromFlow

FlowStream.fromFlow flow

Member

Creates a one-element stream from an effectful value.

Parameters

Name	Type	Description
flow	Flow<'env, 'error, 'value>

Returns

FlowStream<'env, 'error, 'value>

Verification Examples

FlowStream.fromFlow (Flow.ok 42)

kind:member

runForEach

FlowStream.runForEach action (FlowStream op)

Member

Executes the stream and performs a synchronous action for each successful value.

Parameters

Name	Type	Description
action	'value -> unit	The function to execute for each value emitted by the stream.
FlowStream op	FlowStream<'env, 'error, 'value>

Returns

Flow<'env, 'error, unit>

Verification Examples

FlowStream.fromSeq ["a"; "b"; "c"]
|> FlowStream.runForEach (printfn "%s")
|> Flow.run ()

kind:member

map

FlowStream.map f (FlowStream op)

Member

Transforms the successful values of a stream using the provided function.

Parameters

Name	Type	Description
f	'v -> 'w	The function to transform each value.
FlowStream op	FlowStream<'env, 'error, 'v>

Returns

FlowStream<'env, 'error, 'w>

Verification Examples

let stream = FlowStream.fromSeq [1; 2; 3] |> FlowStream.map (fun n -> n * 2)

kind:member

mapError

FlowStream.mapError mapper (FlowStream op)

Member

Transforms the typed error channel of a stream.

Parameters

Name	Type	Description
mapper	'error -> 'nextError
FlowStream op	FlowStream<'env, 'error, 'value>

Returns

FlowStream<'env, 'nextError, 'value>

Verification Examples

stream |> FlowStream.mapError DomainError

kind:member

filter

FlowStream.filter predicate (FlowStream op)

Member

Keeps values that satisfy a predicate.

Parameters

Name	Type	Description
predicate	'a -> bool
FlowStream op	FlowStream<'b, 'c, 'a>

Returns

FlowStream<'b, 'c, 'a>

Verification Examples

stream |> FlowStream.filter (fun value -> value > 0)

kind:member

choose

FlowStream.choose chooser (FlowStream op)

Member

Maps and filters values in one operation.

Parameters

Name	Type	Description
chooser	'a -> 'b option
FlowStream op	FlowStream<'c, 'd, 'a>

Returns

FlowStream<'c, 'd, 'b>

Verification Examples

stream |> FlowStream.choose id

kind:member

tapFlow

FlowStream.tapFlow action (FlowStream op)

Member

Runs an effect for each value before emitting the original value.

Parameters

Name	Type	Description
action	'a -> Flow<'b, 'c, unit>
FlowStream op	FlowStream<'b, 'c, 'a>

Returns

FlowStream<'b, 'c, 'a>

Verification Examples

stream |> FlowStream.tapFlow logValue

kind:member

mapFlow

FlowStream.mapFlow mapper (FlowStream op)

Member

Transforms every value with a Flow effect.

Parameters

Name	Type	Description
mapper	'a -> Flow<'b, 'c, 'd>
FlowStream op	FlowStream<'b, 'c, 'a>

Returns

FlowStream<'b, 'c, 'd>

Verification Examples

ids |> FlowStream.mapFlow load

kind:member

take

FlowStream.take count (FlowStream op)

Member

Emits at most count values.

Parameters

Name	Type	Description
count	int
FlowStream op	FlowStream<'a, 'b, 'c>

Returns

FlowStream<'a, 'b, 'c>

Verification Examples

stream |> FlowStream.take 10

kind:member

skip

FlowStream.skip count (FlowStream op)

Member

Skips the first count values.

Parameters

Name	Type	Description
count	int
FlowStream op	FlowStream<'a, 'b, 'c>

Returns

FlowStream<'a, 'b, 'c>

Verification Examples

stream |> FlowStream.skip 10

kind:member

takeWhile

FlowStream.takeWhile predicate (FlowStream op)

Member

Emits values while a predicate remains true.

Parameters

Name	Type	Description
predicate	'a -> bool
FlowStream op	FlowStream<'b, 'c, 'a>

Returns

FlowStream<'b, 'c, 'a>

Verification Examples

stream |> FlowStream.takeWhile (fun value -> value < 100)

kind:member

skipWhile

FlowStream.skipWhile predicate (FlowStream op)

Member

Skips values while a predicate remains true.

Parameters

Name	Type	Description
predicate	'a -> bool
FlowStream op	FlowStream<'b, 'c, 'a>

Returns

FlowStream<'b, 'c, 'a>

Verification Examples

stream |> FlowStream.skipWhile String.IsNullOrEmpty

kind:member

indexed

FlowStream.indexed (FlowStream op)

Member

Emits each value paired with its zero-based index.

Parameters

Name	Type	Description
FlowStream op	FlowStream<'a, 'b, 'c>

Returns

FlowStream<'a, 'b, (int * 'c)>

Verification Examples

stream |> FlowStream.indexed

kind:member

scan

FlowStream.scan folder initial (FlowStream op)

Member

Emits successive accumulator states.

Parameters

Name	Type	Description
folder	'a -> 'b -> 'a
initial	'a
FlowStream op	FlowStream<'c, 'd, 'b>

Returns

FlowStream<'c, 'd, 'a>

Verification Examples

stream |> FlowStream.scan (+) 0

kind:member

distinctUntilChangedBy

FlowStream.distinctUntilChangedBy projection (FlowStream op)

Member

Suppresses consecutive duplicate values according to a projection.

Parameters

Name	Type	Description
projection	'a -> 'b
FlowStream op	FlowStream<'c, 'd, 'a>

Returns

FlowStream<'c, 'd, 'a>

Verification Examples

stream |> FlowStream.distinctUntilChangedBy id

kind:member

append

FlowStream.append (FlowStream right) (FlowStream left)

Member

Concatenates two streams, evaluating the second only after the first ends.

Parameters

Name	Type	Description
FlowStream right	FlowStream<'a, 'b, 'c>
FlowStream left	FlowStream<'a, 'b, 'c>

Returns

FlowStream<'a, 'b, 'c>

Verification Examples

first |> FlowStream.append second

kind:member

collect

FlowStream.collect mapper (FlowStream outer)

Member

Maps each value to a stream and concatenates the resulting streams.

Parameters

Name	Type	Description
mapper	'a -> FlowStream<'b, 'c, 'd>
FlowStream outer	FlowStream<'b, 'c, 'a>

Returns

FlowStream<'b, 'c, 'd>

Verification Examples

stream |> FlowStream.collect FlowStream.fromSeq

kind:member

zip

FlowStream.zip (FlowStream right) (FlowStream left)

Member

Pairs values from two streams until either stream ends.

Parameters

Name	Type	Description
FlowStream right	FlowStream<'a, 'b, 'c>
FlowStream left	FlowStream<'a, 'b, 'd>

Returns

FlowStream<'a, 'b, ('d * 'c)>

Verification Examples

left |> FlowStream.zip right

kind:member

runFold

FlowStream.runFold folder initial (FlowStream op)

Member

Folds a stream into one value inside Flow.

Parameters

Name	Type	Description
folder	'state -> 'a -> 'state
initial	'state
FlowStream op	FlowStream<'env, 'error, 'a>

Returns

Flow<'env, 'error, 'state>

Verification Examples

stream |> FlowStream.runFold (+) 0

kind:member

runCollect

FlowStream.runCollect stream

Member

Collects all emitted values into a list.

Parameters

Name	Type	Description
stream	FlowStream<'a, 'b, 'c>

Returns

Flow<'a, 'b, 'c list>

Verification Examples

stream |> FlowStream.runCollect

kind:member

runDrain

FlowStream.runDrain stream

Member

Consumes a stream and ignores its values.

Parameters

Name	Type	Description
stream	FlowStream<'a, 'b, 'c>

Returns

Flow<'a, 'b, unit>

Verification Examples

stream |> FlowStream.runDrain

kind:member

runForEachFlow

FlowStream.runForEachFlow action (FlowStream op)

Member

Runs an effectful action for every stream value.

Parameters

Name	Type	Description
action	'a -> Flow<'env, 'error, unit>
FlowStream op	FlowStream<'env, 'error, 'a>

Returns

Flow<'env, 'error, unit>

Verification Examples

stream |> FlowStream.runForEachFlow save