Unison is a new programming language, currently under active development. It's a modern, statically-typed purely functional language, similar to Haskell, but with the ability to describe entire distributed systems with a single program. Here's an example of a distributed map-reduce implementation:

-- comments start with `--`
mapReduce loc fn ifEmpty reduce data = match split data with
  Empty          -> ifEmpty
  One a          -> fn a
  Two left right ->
    fl = at loc '(mapReduce loc fn ifEmpty reduce !left)
    fr = at loc '(mapReduce loc fn ifEmpty reduce !right)
    op !fl !fr

This function can be either simulated locally (possibly with faults injected for testing purposes), or run atop a distributed pool of compute.

If you'd like to learn more about the project, this Strange Loop talk is a good introduction. You can also follow along with project website or you can also say hello or lurk in the Slack chat.

We are currently alpha testing Unison. If you'd like to participate in alpha testing, you can go to the docs site to get started.

If these instructions don't work for you or are incomplete, please file an issue.

The build uses Stack. If you don't already have it installed, follow the install instructions for your platform. (Hint: brew update && brew install stack)

$ git clone https://github.com/unisonweb/unison.git
$ cd unison
$ stack --version # we'll want to know this version if you run into trouble
$ stack build && stack exec tests && stack exec unison

See development.markdown for a list of build commands you'll likely use during development.