frappe - FRP library for Rust

Functional Reactive Programming library inspired by Carboxyl. It's designed to efficiently pass objects around by avoiding cloning as much as possible, and by evaluating signals only when changes happen. Threading is now supported (experimental), streams and signals can be freely moved and used between threads.

Documentation

Usage

use frappe::Sink;

fn main() {
    // values are sent from a sink..
    let sink = Sink::new();
    // ..into a stream chain
    let stream = sink.stream().inspect(|a| println!("--sent: {}", a));

    // `hold` creates a Signal that stores the last value sent to the stream
    let last = stream.hold(0);

    // stream callbacks receive a MaybeOwned<T> argument, so we need to deref the value
    let sum = stream.fold(0, |acc, n| acc + *n);

    let half_even = stream
        // the methods filter, map, fold are analogous to Iterator operations
        .filter(|n| n % 2 == 0)
        .map(|n| *n / 2)
        .fold(Vec::new(), |mut vec, n| {
            vec.push(*n);
            vec
        }); // note: .collect::<Vec<_>>() does the same

    // we can send individual values
    sink.send(6);
    sink.send(42);
    sink.send(-1);
    // or multiple ones at once
    sink.feed(10..15);

    // `sample` gets a copy of the value stored in the signal
    println!("last: {}", last.sample());
    // printing a signal samples it
    println!("sum: {}", sum);
    // `take` moves the value out of the signal
    println!("half_even: {:?}", half_even.take());
}