switch_bitch.rb

class Match
  attr_accessor :matcher, :action

  def initialize(matcher, action)
    @matcher, @action = matcher, action
  end
end

class SwitchBitch
  def initialize(value, &block)
    @value = value
    @match_list = []

    instance_exec &block
  end

  def case_(matcher, &block)
    @match_list << Match.new(matcher, block)
  end

  def breakout
    throw :breakout
  end

  def find_first_match_index
    @match_list.find_index { |m| m.matcher == @value }
  end

  def run
    if !(index = find_first_match_index)
      puts "no matches!"
      return
    end

    catch :breakout do
      @match_list[index..-1].each do |match|
        instance_exec(&match.action)
      end
    end
  end
end

def switch(value, &block)
  SwitchBitch.new(value, &block).run
  nil
end