#futures #async #future #derive #enum

macro futures-enum

#[derive(Future, Stream, Sink, AsyncRead, AsyncWrite, AsyncSeek, AsyncBufRead)] for enums

18 releases

0.1.17 Jan 5, 2021
0.1.16 Dec 29, 2020
0.1.15 Nov 6, 2020
0.1.13 Jun 2, 2020
0.1.5 Mar 4, 2019

#446 in Asynchronous

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futures-enum

crates.io docs.rs license rustc build status

#[derive(Future, Stream, Sink, AsyncRead, AsyncWrite, AsyncSeek, AsyncBufRead)] for enums.

Usage

Add this to your Cargo.toml:

[dependencies]
futures-enum = "0.1.16"
futures = "0.3"

Compiler support: requires rustc 1.36+

Examples

use futures_enum::*;
use std::future::Future;

#[derive(Future, Stream, Sink, AsyncRead, AsyncWrite, AsyncSeek, AsyncBufRead)]
enum Either<A, B> {
    A(A),
    B(B),
}

fn foo(x: i32) -> impl Future<Output = i32> {
    if x < 0 {
        Either::A(async { 1 })
    } else {
        Either::B(async move { x })
    }
}

futures-enum works well even if the dependency contains only sub-crates such as futures-core, futures-io, futures-sink, etc.

See auto_enums crate for how to automate patterns like this.

Supported traits

Related Projects

  • auto_enums: A library for to allow multiple return types by automatically generated enum.
  • derive_utils: A procedural macro helper for easily writing [derives macros][proc-macro-derive] for enums.
  • io-enum: #[derive(Read, Write, Seek, BufRead)] for enums.
  • iter-enum: #[derive(Iterator, DoubleEndedIterator, ExactSizeIterator, Extend)] for enums.

License

Licensed under either of Apache License, Version 2.0 or MIT license 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.

Dependencies

~0.4–1MB
~22K SLoC