#PNA2011 Ruby DSL example

fake_web_dsl.rb

def application(name, &block)
  $app = Application.new
  $app.name = name
  $app.instance_eval(&block)
end

class Application
  attr_accessor :name

  def initialize
    @responders = {}
  end

  def open(path)
    responder = @responders[path]
    if responder
      responder.handle
    else
      puts 'no respond'
    end
  end

  def respond(path, &block)
    @responders[path] = Responder.new(&block)
  end
end

class Responder
  def initialize(&block)
    @block = block
  end

  def handle
    instance_eval(&@block)
  end

  def render(words)
    puts words
  end
end

# ----

application 'Test' do
  respond '/' do
    render 'ok!'
  end

  respond '/test' do
    render 'welcome'
  end
end

# ----

$app.open '/'
$app.open '/test'
$app.open '/404'