Module frappe::stream

The Stream type.

Streams provide a composable way to handle events that's focused on data instead of callbacks. You can think of it as a data processing pipeline. Streams do all their work on the sender side, so they're "eager".

A stream chain begins with a Sink that receives the input values and can send those values to multiple streams. Operations applied to a Stream are applied to all the values that pass through it. The result of a stream chain be viewed with the Stream::observe method or stored on a Signal. All the objects that result from stream operations contain an internal reference to it's parent, so dropping intermediate temporary streams (like the ones created from chaining methods) won't break the chain.

This implementation of Stream distributes the data as MaybeOwned<T> values to avoid unnecessary cloning, so the first observers will receive a MaybeOwned::Borrowed value, and the last one will receive aMaybeOwned::Owned. This also allows sending values as a reference with an arbitrary lifetime, not just &'static refs.

Example

use frappe::Sink;

let sink1 = Sink::new();
let sink2 = Sink::new();
let stream = sink1.stream().map(|x| *x + 1)
            .merge(&sink2.stream().map(|x| *x * 2));
let signal = stream.hold(0);

sink1.send(10);
assert_eq!(signal.sample(), 11);

sink2.send(10);
assert_eq!(signal.sample(), 20);

Structs

Sender	Sends values into a stream.
Sink	A source of events that feeds the streams connected to it.
Stream	A stream of discrete events sent over time.