class GitHub::Markup::Markdown

def initialize
  super(/md|mkdn?|mdwn|mdown|markdown|litcoffee/)
end

def load
  return if @renderer
  MARKDOWN_GEMS.each do |gem_name, renderer|
    if try_require(gem_name)
      @renderer = renderer
      return
    end
  end
  raise LoadError, "no suitable markdown gem found"
end

def render(content)
  load
  @renderer.call(content)
end

def try_require(file)
  require file
  true
rescue LoadError
  false
end