Minimal and simpler alternative to the futures crate.

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  • No required std / alloc
  • No macros at all (no pin_mut!() macros inserting unsafe blocks into your code)
  • No slow compiling proc macros (fast compile times)
  • No dependencies
  • No cost (True zero-cost abstractions!)
  • No pain (API super easy to learn & use!)
  • No unsafe code left for you to write for working with Futures

Table of Contents

Getting Started

Add the following to your Cargo.toml.

pasts = "0.4"


This example goes in a loop and prints "One" every second, and "Two" every other second. After 5 prints, the program prints "One" once more, then terminates.


use pasts::prelude::*;
use pasts::CvarExec;

use std::cell::RefCell;

async fn timer_future(duration: std::time::Duration) {
    pasts::spawn_blocking(move || std::thread::sleep(duration)).await

async fn one(state: &RefCell<usize>) {
    println!("Starting task one");
    while *state.borrow() < 5 {
        timer_future(std::time::Duration::new(1, 0)).await;
        let mut state = state.borrow_mut();
        println!("One {}", *state);
        *state += 1;
    println!("Finish task one");

async fn two(state: &RefCell<usize>) {
    println!("Starting task two");
    loop {
        timer_future(std::time::Duration::new(2, 0)).await;
        let mut state = state.borrow_mut();
        println!("Two {}", *state);
        *state += 1;

async fn example() {
    let state = RefCell::new(0);
    let mut task_one = one(&state);
    let mut task_two = two(&state);
    let mut tasks = [task_one.fut(), task_two.fut()];;

fn main() {
    static EXECUTOR: CvarExec = CvarExec::new();



API documentation can be found on


Some APIs are only available with the std feature enabled. Other APIs only require the alloc feature. APIs that require features are labeled so on You can use no-std with or without the alloc feature (which corresponds to the alloc crate, just as std corresponds to the std crate).


You can use the changelog to facilitate upgrading this crate as a dependency.


Licensed under either of

at your option.


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.

Contributors are always welcome (thank you for being interested!), whether it be a bug report, bug fix, feature request, feature implementation or whatever. Don't be shy about getting involved. I always make time to fix bugs, so usually a patched version of the library will be out a few days after a report. Features requests will not complete as fast. If you have any questions, design critques, or want me to find you something to work on based on your skill level, you can email me at [email protected]. Otherwise, here's a link to the issues on GitHub. Before contributing, check out the contribution guidelines, and, as always, make sure to follow the code of conduct.


Minimal and simpler alternative to the futures crate.

Pasts Info

⭐ Stars 14
🔗 Homepage
🔗 Source Code
🕒 Last Update 9 months ago
🕒 Created 2 years ago
🐞 Open Issues 0
➗ Star-Issue Ratio Infinity
😎 Author AldaronLau