mobx-ruby

_demo.rb

require 'mobx'

Mobx.init

class Session
  extend Mobx::Extension
  observable :user
  observable :company
end

session = Session.new

include Mobx::Extension

autorun do
  puts "User: #{session.user}"
end

reaction -> { session.company } do
  puts "Company: #{session.company}"
end

session.user = "Abc"
session.company = "Blah"

action do
  session.user = "Abc"
  session.user = "Ghi"
  session.user = "Jkl"
  session.company = "Def"
end

# $ ruby mobx-ruby.rb
# User:
# User: Abc
# Company: Blah
# User: Jkl
# Company: Def

autorun.rb

module Mobx
  class Autorun
    def initialize(block)
      @block = block
    end
    def call
      @block.call
    end
  end
end

extension.rb

module Mobx
  module Extension
    def autorun(&block)
      Thread.current['mobx-autorun'] << Mobx::Autorun.new(block)
      block.call
      Thread.current['mobx-autorun'].pop
    end

    def reaction(lambda, &block)
      Thread.current['mobx-autorun'] << Mobx::Autorun.new(block)
      lambda.call
      Thread.current['mobx-autorun'].pop
    end  

    def action(&block)
      Mobx::Transaction.new(block).call
    end

    def observable(attr_name, value=nil)
      define_method(attr_name) do
        @observables ||= {}
        @observables[attr_name] ||= Mobx::Observable.new(value)
        @observables[attr_name].get 
      end

      define_method("#{attr_name}=") do |value|
        @observables ||= {}
        if @observables.has_key?(attr_name)
          @observables[attr_name].set(value)
        else  
          @observables[attr_name] = Mobx::Observable.new(value) 
        end
      end
    end
  end
end

mobx.rb

require 'mobx/observable'
require 'mobx/autorun'
require 'mobx/transaction'
require 'mobx/extension'

module Mobx
  def init
    Thread.current['mobx-autorun'] = []
  end
end

observable.rb

module Mobx
  class Observable
    def initialize(value)
      @value = value
      @observers = []
    end

    def get
      @observers += Thread.current['mobx-autorun'] if Thread.current['mobx-autorun']
      @value
    end

    def set(value)
      @value = value
      if Thread.current['mobx-transaction']
        Thread.current['mobx-transaction'].schedule(@observers)
      else
        @observers.each { |observer| observer.call }
      end
      @value
    end
  end
end

transaction.rb

module Mobx
  class Transaction
    def initialize(block)
      @block = block
      @scheduled = []
    end 

    def call
      if Thread.current['mobx-transaction']
        @block.call
      else
        Thread.current['mobx-transaction'] = self
        @block.call
        Thread.current['mobx-transaction'] = nil
        @scheduled.each { |observer| observer.call }
        @scheduled = []
      end
    end

    def schedule(observers)
      @scheduled = (@scheduled + observers).uniq
    end 
  end
end