carboxyl 0.2.0 - Docs.rs

Carboxyl is a library for functional reactive programming in Rust, a functional and composable approach to handle events in interactive applications. Read more in the docs…

Note that currently Rust nightly is required to use this crate!

Usage example

Here is a simple example of how you can use the primitives provided by Carboxyl. First of all, events can be sent into a sink. From a sink one can create a stream of events. Streams can also be filtered, mapped and merged. A signal is an abstraction of a value that may change over time. One can e.g. hold the last event from a stream in a signal.

use carboxyl::Sink;

let sink = Sink::new();
let stream = sink.stream();
let signal = stream.hold(3);

// The current value of the signal is initially 3
assert_eq!(signal.sample(), 3);

// When we fire an event, the signal get updated accordingly
sink.send(5);
assert_eq!(signal.sample(), 5);

One can also directly iterate over the stream instead of holding it in a signal:

let mut events = stream.events();
sink.send(4);
assert_eq!(events.next(), Some(4));

Streams and signals can be combined using various primitives. We can map a stream to another stream using a function:

let squares = stream.map(|x| x * x).hold(0);
sink.send(4);
assert_eq!(squares.sample(), 16);

Or we can filter a stream to create a new one that only contains events that satisfy a certain predicate:

let negatives = stream.filter(|&x| x < 0).hold(0);

// This won't arrive at the signal.
sink.send(4);
assert_eq!(negatives.sample(), 0);

// But this will!
sink.send(-3);
assert_eq!(negatives.sample(), -3);

There are a couple of other primitives to compose streams and signals:

merge two streams of events of the same type.
Make a snapshot of a signal, whenever a stream fires an event.
lift! an ordinary function to a function on signals.
switch between different signals using a signal containing a signal.

See the documentation for details.

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License or GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License and the GNU Lesser General Public License along with this program. If not, see http://www.gnu.org/licenses/.