Processing futures and promises asynchronously

[Daniel Hinojosa]

I am looking for a functional, non-blocking way to process the return of a future. In the Scala world, you can use map, flatMap, and foreach to process the return values of a future asynchronously.  In Clojure, dereferencing blocks, so that makes it kind of rough since we have to set up our constructs.  If anyone can steer me on the "Functional Clojure way" to process futures and promises that would be greatly appreciated. ;)

[Leonardo Borges]

Hi Daniel,

Since you're used to Scala futures, you might find this library easy to get started with:

https://github.com/leonardoborges/imminent (A composable Futures library for Clojure)

The next release will also include ClojureScript support.

Cheers,

Leonardo Borges

www.leonardoborges.com

On Tue, Oct 27, 2015 at 9:46 AM Daniel Hinojosa <dh.evolu...@gmail.com> wrote:

I am looking for a functional, non-blocking way to process the return of a future. In the Scala world, you can use map, flatMap, and foreach to process the return values of a future asynchronously.  In Clojure, dereferencing blocks, so that makes it kind of rough since we have to set up our constructs.  If anyone can steer me on the "Functional Clojure way" to process futures and promises that would be greatly appreciated. ;)

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[Matching Socks]

See also: Zach Tellman's "Manifold"

http://aleph.io/manifold/rationale.html

http://aleph.io/manifold/deferreds.html

[Chris Murphy]

Here are some discussions around the issue:

http://stackoverflow.com/questions/31832599/future-failure-in-clojure

~ Chris

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[Alejandro Gómez]

Hi Daniel,

Allow me to recommend a couple of libraries:
- promissum (https://github.com/funcool/promissum) is a composable
promise/future library for Clojure (built on top of jdk8 completable
futures)
- promesa (https://github.com/funcool/promesa) is a wrapper around the
Bluebird JS promise library

They both integrate nicely with cats (https://github.com/funcool/cats),
which lets you write asynchronous code like it was synchronous with the
`mlet` macro that desugars into monadic bind. We also have an `alet`
macro that uses applicative bind and thus maximizes concurrency, take a
look at the docs for more details.

cats is also integrated with core.async and manifold libraries, so you
can use the same code regardless of what concrete type you use for
conveying asynchronous values.

Regards,

Al

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[Daniel Hinojosa]

Amazing feedback everyone. Thank you.

[Stuart Sierra]

core.async and Transducers target some of this, although in a slightly different way. Instead of clojure.core/future, you can use core.async/thread or core.async/go. Instead of flatMap, you can use a `map` Transducer on a channel or in a core.async/pipeline.

–S