LiMonad

LiMonad is a tiny library for building monads.

Here are some examples of how to build common monads with LiMonad:

Maybe Monad

Example:

MaybeMonad >>
    -> x { 5 / x unless x == 0 } >>
    -> x { x + 1 } >>
    -> x { 3 * x } >>
    -> x { Math.log(x) unless x < 0 } >>
    -> x { x.round }

Monad Definition:

class MaybeMonad < LiMonad
  def bind(f, g, *args)
    result = f[*args]
    g[result] if result
  end
end

Logger Monad

Example:

LoggerMonad >>
    -> x { [x * x, "#{x} was squared"] } >>
    -> x { [x / 2, "#{x} was halved"]  }

Monad Definition:

class LoggerMonad < LiMonad
  def bind(f, g, *args)
    f_result, f_log = f[*args]
    g_result, g_log = g[f_result]
    [g_result, "#{f_log}\n#{g_log}"]
  end

  def unit(g, *args)
    [g[*args], args.inspect]
  end
end

Installation

Add this line to your application's Gemfile:

gem 'limonad'

And then execute:

$ bundle

Or install it yourself as:

$ gem install limonad

Contributing

1. Fork it ( https://github.com/nakhli/limonad/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 a new Pull Request

License

Licensed under the MIT License.

Copyright Chaker Nakhli.