https://github.com/teohhanhui/callbag-rs
Rust implementation of the callbag spec for reactive/iterable programming
https://github.com/teohhanhui/callbag-rs
callbag frp iterable observable reactive rust stream
Last synced: 7 months ago
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Rust implementation of the callbag spec for reactive/iterable programming
- Host: GitHub
- URL: https://github.com/teohhanhui/callbag-rs
- Owner: teohhanhui
- License: apache-2.0
- Created: 2021-11-03T14:58:50.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2022-05-11T14:03:39.000Z (about 3 years ago)
- Last Synced: 2024-10-19T14:03:23.218Z (8 months ago)
- Topics: callbag, frp, iterable, observable, reactive, rust, stream
- Language: Rust
- Homepage:
- Size: 240 KB
- Stars: 30
- Watchers: 4
- Forks: 2
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE-APACHE
Awesome Lists containing this project
README
# callbag-rs
Rust implementation of the [callbag spec][callbag-spec] for reactive/iterable programming.
Basic [callbag][callbag-spec] factories and operators to get started with.
**Highlights:**
- Supports reactive stream programming
- Supports iterable programming (also!)
- Same operator works for both of the above
- Extensible
Imagine a hybrid between an [Observable][tc39-observable] and an [(Async)Iterable][tc39-async-iteration], that's what
callbags are all about. It's all done with a few simple callbacks, following the [callbag spec][callbag-spec].
[![CI][ci-badge]][ci-url]
[![Crates.io][crates-badge]][crates-url]
[![Documentation][docs-badge]][docs-url]
[![MIT OR Apache-2.0 licensed][license-badge]][license-url]
## Examples
### Reactive programming examples
Pick the first 5 odd numbers from a clock that ticks every second, then start observing them:
```rust
use async_nursery::Nursery;
use crossbeam_queue::SegQueue;
use std::{sync::Arc, time::Duration};
use callbag::{filter, for_each, interval, map, pipe, take};
let (nursery, nursery_out) = Nursery::new(async_executors::AsyncStd);
let actual = Arc::new(SegQueue::new());
pipe!(
interval(Duration::from_millis(1_000), nursery.clone()),
map(|x| x + 1),
filter(|x| x % 2 == 1),
take(5),
for_each({
let actual = Arc::clone(&actual);
move |x| {
println!("{x}");
actual.push(x);
}
}),
);
drop(nursery);
async_std::task::block_on(nursery_out);
assert_eq!(
&{
let mut v = vec![];
while let Some(x) = actual.pop() {
v.push(x);
}
v
}[..],
[1, 3, 5, 7, 9]
);
```
### Iterable programming examples
From a range of numbers, pick 5 of them and divide them by 4, then start pulling those one by one:
```rust
use crossbeam_queue::SegQueue;
use std::sync::Arc;
use callbag::{for_each, from_iter, map, pipe, take};
#[derive(Clone)]
struct Range {
i: usize,
to: usize,
}
impl Range {
fn new(from: usize, to: usize) -> Self {
Range { i: from, to }
}
}
impl Iterator for Range {
type Item = usize;
fn next(&mut self) -> Option {
let i = self.i;
if i <= self.to {
self.i += 1;
Some(i)
} else {
None
}
}
}
let actual = Arc::new(SegQueue::new());
pipe!(
from_iter(Range::new(40, 99)),
take(5),
map(|x| x as f64 / 4.0),
for_each({
let actual = Arc::clone(&actual);
move |x| {
println!("{x}");
actual.push(x);
}
}),
);
assert_eq!(
&{
let mut v = vec![];
while let Some(x) = actual.pop() {
v.push(x);
}
v
}[..],
[10.0, 10.25, 10.5, 10.75, 11.0]
);
Ok::<(), Box>(())
```
## API
The list below shows what's included.
### Source factories
- [from_iter](https://docs.rs/callbag/latest/callbag/fn.from_iter.html)
- [interval](https://docs.rs/callbag/latest/callbag/fn.interval.html)
### Sink factories
- [for_each](https://docs.rs/callbag/latest/callbag/fn.for_each.html)
### Transformation operators
- [map](https://docs.rs/callbag/latest/callbag/fn.map.html)
- [scan](https://docs.rs/callbag/latest/callbag/fn.scan.html)
- [flatten](https://docs.rs/callbag/latest/callbag/fn.flatten.html)
### Filtering operators
- [take](https://docs.rs/callbag/latest/callbag/fn.take.html)
- [skip](https://docs.rs/callbag/latest/callbag/fn.skip.html)
- [filter](https://docs.rs/callbag/latest/callbag/fn.filter.html)
### Combination operators
- [merge!](https://docs.rs/callbag/latest/callbag/macro.merge.html)
- [concat!](https://docs.rs/callbag/latest/callbag/macro.concat.html)
- [combine!](https://docs.rs/callbag/latest/callbag/macro.combine.html)
### Utilities
- [share](https://docs.rs/callbag/latest/callbag/fn.share.html)
- [pipe!](https://docs.rs/callbag/latest/callbag/macro.pipe.html)
## Terminology
- **source**: a callbag that delivers data
- **sink**: a callbag that receives data
- **puller sink**: a sink that actively requests data from the source
- **pullable source**: a source that delivers data only on demand (on receiving a request)
- **listener sink**: a sink that passively receives data from the source
- **listenable source**: source which sends data to the sink without waiting for requests
- **operator**: a callbag based on another callbag which applies some operation
## License
Licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or https://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or https://opensource.org/licenses/MIT)
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as
defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.
## Acknowledgements
Thanks to André Staltz ([@staltz](https://github.com/staltz)) for creating the [callbag spec][callbag-spec].
This library is a port of . Some inspiration was taken from
.
Many thanks to the awesome folks on the [Rust Users Forum](https://users.rust-lang.org/) for their help, especially:
- Alice Ryhl ([alice](https://users.rust-lang.org/u/alice))
- Jessa ([jessa0](https://users.rust-lang.org/u/jessa0))
[callbag-spec]: https://github.com/callbag/callbag
[ci-badge]: https://github.com/teohhanhui/callbag-rs/actions/workflows/ci.yml/badge.svg
[ci-url]: https://github.com/teohhanhui/callbag-rs/actions/workflows/ci.yml
[crates-badge]: https://img.shields.io/crates/v/callbag
[crates-url]: https://crates.io/crates/callbag
[docs-badge]: https://img.shields.io/docsrs/callbag
[docs-url]: https://docs.rs/callbag
[license-badge]: https://img.shields.io/crates/l/callbag
[license-url]: https://github.com/teohhanhui/callbag-rs#license
[tc39-async-iteration]: https://github.com/tc39/proposal-async-iteration
[tc39-observable]: https://github.com/tc39/proposal-observable