attr_config.yml

navlink:
  data-transition: fade
sidebar:
  data-role: sidebar
  data-transition: slide
  data-position: left

# ...

hello.haml

#content(app_helper)
  #header
    %ul.navigation(app_toolbar)
      %li.navigation(app_navlink) Link 1
      %li.navigation(app_navlink) Link 2
  #main(app_window)
    Hello World
  #sidebar(app_sidebar)
  #footer

helpers.rb

def method_missing(meth)
  if meth ~= /^app_(.*)$/
    ATTR_CONFIG[$1].to_hash
  end
end