shoes_down.rb

require 'kramdown'

class ShoesDown
  attr_reader :app, :kramdown_document, :type, :value, :attr, :children, :options

  def initialize(markdown)
    @kramdown_document = Kramdown::Document.new(markdown, input: 'GFM')
  end

  def draw(app)
    @app = app
    convert(kramdown_document.root)
  end

  # @param el [Kramdown::Element] The element to convert
  def convert(el)
    @type, @value, @attr, @children, @options =
      el.type, el.value, el.attr, el.children, el.options
    send(type)
  end

  def convert_children
    children.each {|element| convert(element) }
  end

  # Each Kramdown element type gets corresponds with a method here,
  # See https://github.com/gettalong/kramdown/blob/master/lib/kramdown/element.rb for a list of types

  def method_missing(type, *args)
    puts "Kramdown #{type} element not supported"
    convert_children
  end

  def text
    app.para value
  end

  def blank
    app.para value
  end

  def header
    case options[:level]
    when 1
      app.banner children.map(&:value).join
    when 2
      app.title children.map(&:value).join
    when 3
      app.subtitle children.map(&:value).join
    end
  end
end

Shoes.app do
  ShoesDown.new(<<MD).draw(self)
# Hello from Markdown

## Subtitles and all

Hello good friends, Markdown and Shoes can play along just fine.

MD

end