https://github.com/kixunil/enum_future

A simple macro for creating `Future`-implementing enums containing futures.
https://github.com/kixunil/enum_future

Last synced: about 2 months ago
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A simple macro for creating `Future`-implementing enums containing futures.

• Host: GitHub
• URL: https://github.com/kixunil/enum_future
• Owner: Kixunil
• Created: 2019-01-28T10:13:26.000Z (almost 6 years ago)
• Default Branch: master
• Last Pushed: 2019-01-28T10:15:12.000Z (almost 6 years ago)
• Last Synced: 2024-11-24T20:08:48.162Z (about 2 months ago)
• Language: Rust
• Size: 1.95 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
enum future

===========

A simple macro for creating `Future`-implementing enums containing futures.

About

-----

The `enum_future` macro can be used as an alternative to `futures::Either` if more than two variants

are desired or if one wants to give them more meaningful names. The enum is generic, in order to allow use with complicated or unname-able types (combinators, closures, impl Future).

This macro doesn't allow for creating `pub` enums, documenting them or deriving any other

trait. This should be fine in most cases, as it's intended to be used mainly in `match`

expressions returning different futures.

Derive macro would certainly provide more flexibility, but it'd also be more complicated and

this simple macro solves my problem. If anyone is interested in contributing proc macro

version, I'd be very happy to merge a PR!

This crate is `no_std` and pre-2018-compatible, since it doesn't need anything fancy from neither `std`

nor 2018 edition.

Example

-------

```rust

#[macro_use]

extern crate enum_future;

use enum_future::futures::future::{Future, ok, err};

fn make_future(input: u64) -> impl Future {

    enum_future!(Ret, Zero, One, Other);

    match input {

        0 => Ret::Zero(ok(false)),

        1 => Ret::One(ok(true)),

        _ => Ret::Other(err("Invalid input")),

    }

}

fn main() {

    assert_eq!(make_future(42).wait(), Err("Invalid input"));

}

```

License

-------

MITNFA