https://github.com/rufflewind/futures_become

Tail-call elimination for futures
https://github.com/rufflewind/futures_become

concurrency futures rust

Last synced: 11 months ago
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Tail-call elimination for futures

• Host: GitHub
• URL: https://github.com/rufflewind/futures_become
• Owner: Rufflewind
• Created: 2017-04-04T07:19:50.000Z (about 9 years ago)
• Default Branch: master
• Last Pushed: 2021-06-06T08:10:22.000Z (about 5 years ago)
• Last Synced: 2025-03-14T15:49:21.976Z (about 1 year ago)
• Topics: concurrency, futures, rust
• Language: Rust
• Size: 1.13 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# `futures_become`

[![Build Status](https://github.com/Rufflewind/futures/actions/workflows/build.yml_become.svg?branch=master)](https://github.com/Rufflewind/futures/actions/workflows/build.yml_become)

[Documentation for the `master` branch](https://rufflewind.com/futures_become)

Tail-call elimination for [`futures`](https://crates.io/crates/futures).

Dispatching a long chain of futures built with `and_then` may result in a

linear cost.  One could avoid this using e.g. `loop_fn`, but this is hard to

compose due to shared state.

This package provides an alternative interface through a `Become` construct,

which acts as a kind of "tail-call elimination" at the futures level.  Turns

out it can be done without modifying the existing `Future` trait, but at the

cost of changing `Error` type of each future to a wrapped one using `Become`.

Then, returning `Err(Become::Become(next))` can be used to indicate that the

current future should be discarded and replaced with `next`.  This of course

means that we have to box each future, as the type of the current future could

be wildly different from that of the `next` future.