12 releases
0.4.7 | Jun 10, 2020 |
---|---|
0.4.6 | Aug 23, 2019 |
0.4.5 | Mar 14, 2019 |
0.4.4 | Jan 25, 2019 |
0.1.0 | Mar 19, 2017 |
#9 in #functional-reactive-programming
Used in 2 crates
69KB
1.5K
SLoC
frappe - FRP library for Rust
Frappe is a concurrent Event-Driven FRP library. It aims to provide a simple, efficient and Rust-idiomatic way to write interactive applications in a declarative way.
Events are processed in streams, and they can be accumulated and read using signals.
Also stream events can be turned into futures using the Stream::next
method, so you can
listen to them via async/await.
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
.map(|v| format!("{:?}", v));
// 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);
println!("half_even: {}", half_even);
}
You can also check the frappe-gtk examples for more complex usage examples on GUI applications.
Dependencies
~1.5MB
~27K SLoC