# microKanren in Ruby

A port of microKanren, a minimalistic logic programming language, to Ruby.

## Description

This is a port of [microKanren](http://webyrd.net/scheme-2013/papers/HemannMuKanren2013.pdf)
to Ruby. It is an almost exact translation of
[the original implementation](https://github.com/jasonhemann/microKanren),
which was written for [Petite Chez Scheme](http://www.scheme.com/petitechezscheme.html).

## Installation

Add this line to your application's Gemfile:

    gem 'micro_kanren'

And then execute:

    $ bundle

Or install it yourself as:

    $ gem install micro_kanren

## Usage

The following example demonstrates how MicroKanren can be used from the console:

```ruby
> require 'micro_kanren'
> include MicroKanren::Core
> include MicroKanren::MiniKanrenWrappers

> res = call_fresh(-> (q) { eq(q, 5) }).call(empty_state)
> puts lprint(res)
(((([0] . 5)) . 1))
```

See the
[spec file](https://github.com/jsl/ruby_ukanren/blob/master/spec/micro_kanren/core_spec.rb)
for more examples. The spec file is almost an exact port of the [microKanren tests
written in Scheme](https://github.com/jasonhemann/microKanren/blob/master/microKanren-test.scm).

## Credits

The code in this gem is closely based on the following sources:

* The [microKanren paper](http://webyrd.net/scheme-2013/papers/HemannMuKanren2013.pdf)
  by Jason Hemann and Daniel P. Friedman. I read this paper a couple of times, and
  will probably have to read it a few more before I have a better understanding
  about what this code is doing and how to write more effective logic programs.
* This code is also in parts copied from
  [Scott Vokes' port of microKanren to Lua](https://github.com/silentbicycle/lua-ukanren).
  It was great to have the Lua code as a second example of the implementation in
  the paper, and it made my job especially easy since Lua is so similar to Ruby.

## Dependencies

This project requires Ruby 2.0 or higher. You can see which Rubies work with
this project in the [Travis CI Build Status](https://travis-ci.org/jsl/ruby_ukanren).

## Contributing

1. Fork it ( http://github.com/jsl/ruby_ukanren/fork )
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request

## Build Status

[![Build Status](https://travis-ci.org/jsl/ruby_ukanren.png)](https://travis-ci.org/jsl/ruby_ukanren)