bquarp v0.5.1 Reactivity.DSL.EventStream View Source

The DSL for distributed reactive programming, specifically, operations applicable to Event Streams.

Link to this section Summary

Functions

Delays each produced item by the given interval.

Filters out values that have already been produced at some point.

Applies a procedure to the values of an Event Stream without changing them. Generally used for side effects.

Filters out the Event Streams values that do not satisfy the given predicate.

Creates an Event Stream from a plain Observable.

Creates an Event Stream from a Signal Observable and tags it with the given guarantees.

Transforms the Event Stream into a Behaviour.

Checks if the given argument is an Event Stream.

Merges multiple Event Streams together The resulting Event Stream carries the events of all composed Event Streams as they arrived.

Filters out values that are equal to the most recently produced value.

Merges multiple Event Streams together The resulting Event Stream carries the events of all composed Event Streams in a round-robin fashion.

Applies a given procedure to the values of an Event Stream and its previous result. Works in the same way as the Enum.scan function

Switches from an intial Event Stream to newly supplied Behaviours.

Switches from one Event Stream to another on an event occurrence.

Link to this section Functions

Delays each produced item by the given interval.

Filters out values that have already been produced at some point.

If no Guarantee is provided, it does not alter the Event Stream Messages. The consequences of using this operator in this way are left to the developer.

If however a Guarantee is provided, it is attached to the resulting Event Stream as its new Guarantee, replacing any previous ones. This is reflected in the Message Contexts. This can be considered to be the creation of a new source Signal with the given Guarantee in a stratified dependency graph.

Applies a procedure to the values of an Event Stream without changing them. Generally used for side effects.

Link to this function

filter(arg, pred, new_cg) View Source

Filters out the Event Streams values that do not satisfy the given predicate.

The expected function should take one argument, the value of an Observable and return a Boolean: true if the value should be produced, false if the value should be discarded.

If no Guarantee is provided, the merge does not alter the Event Stream Messages. The consequences of using this operator in this way are left to the developer.

If however a Guarantee is provided, it is attached to the resulting Event Stream as its new Guarantee, replacing any previous ones. This is reflected in the Message Contexts. Thus, filtering in this way can be considered to be the creation of a new source Signal with the given Guarantee in a stratified dependency graph.

Creates an Event Stream from a plain Observable.

Attaches the given Guarantee to it if provided. Otherwise attaches the globally defined Guarantee, which is FIFO (the absence of any Guarantee) by default.

Creates an Event Stream from a Signal Observable and tags it with the given guarantees.

The assumption here is that the contexts of the Signal Observable have already been attached. The primitive can be used for Guarantees with non-obvious Contexts (other than e.g. counters) the developer might come up with.

Attaches the given Guarantee to it if provided without changing the context. Otherwise attaches the globally defined Guarantee, which is FIFO (the absence of any Guarantee) by default.

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from_signal_obs(sobs, gs) View Source

Transforms the Event Stream into a Behaviour.

Checks if the given argument is an Event Stream.

Merges multiple Event Streams together The resulting Event Stream carries the events of all composed Event Streams as they arrived.

If no Guarantee is provided, the merge does not alter the Event Stream Messages. A necessary condition for this operation to be valid then is that the given Event Streams all carry the same Guarantees. The consequences of using this operator in this way are left to the developer.

If however a Guarantee is provided, it is attached to the resulting Event Stream as its new Guarantee, replacing any previous ones. This is reflected in the Message Contexts. Thus, merging in this way can be considered to be the creation of a new source Signal with the given Guarantee in a stratified dependency graph.

Filters out values that are equal to the most recently produced value.

If no Guarantee is provided, it does not alter the Event Stream Messages. The consequences of using this operator in this way are left to the developer.

If however a Guarantee is provided, it is attached to the resulting Event Stream as its new Guarantee, replacing any previous ones. This is reflected in the Message Contexts. This can be considered to be the creation of a new source Signal with the given Guarantee in a stratified dependency graph.

Merges multiple Event Streams together The resulting Event Stream carries the events of all composed Event Streams in a round-robin fashion.

Should not be used for Event Streams with known discrepancies in event occurrence frequency, since messages will accumulate and create a memory leak.

If no Guarantee is provided, the merge does not alter the Event Stream Messages. A necessary condition for this operation to be valid then is that the given Event Streams all carry the same Guarantees. The consequences of using this operator in this way are left to the developer.

If however a Guarantee is provided, it is attached to the resulting Event Stream as its new Guarantee, replacing any previous ones. This is reflected in the Message Contexts. Thus, merging in this way can be considered to be the creation of a new source Signal with the given Guarantee in a stratified dependency graph.

Link to this function

scan(arg, func, default \\ nil) View Source

Applies a given procedure to the values of an Event Stream and its previous result. Works in the same way as the Enum.scan function:

Enum.scan(1..10, fn(x,y) -> x + y end) => [1, 3, 6, 10, 15, 21, 28, 36, 45, 55]

Switches from an intial Event Stream to newly supplied Behaviours.

Takes an initial Event Stream and a higher-order Event Stream carrying Event Streams. Returns an Event Stream that is at first equal to the initial Event Stream. Each time the higher order Event Stream emits a new Event Stream, the returned Event Stream switches to this new Event Stream.

Requires that all Event Streams carry values of the same type and have the same set of consistency guarantees.

Switches from one Event Stream to another on an event occurrence.

Takes three Event Streams. Returns an Event Stream that emits the events of the first Event Stream until an event on the third Event Stream occurs, at which point the resulting Event Stream switches to the second Event Stream. The value of the switching event is not relevant.

Requires that both Event Streams have the same set of consistency guarantees and carry values of the same type.